Citation
Cesium-137 and other gamma radioactivity in the Florida environment

Material Information

Title:
Cesium-137 and other gamma radioactivity in the Florida environment a study of selected media
Creator:
Roessler, Charles Ervin, 1934-
Publication Date:
Copyright Date:
1967
Language:
English
Physical Description:
xi, 169 l. : illus. ; 28 cm.

Subjects

Subjects / Keywords:
Beef ( jstor )
Diet ( jstor )
Food ( jstor )
Meats ( jstor )
Milk ( jstor )
Nuclides ( jstor )
Radioactive decay ( jstor )
Radionuclides ( jstor )
Soils ( jstor )
Vegetables ( jstor )
Cesium -- Effect of radiation on ( lcsh )
Dissertations, Academic -- Environmental Engineering Sciences -- UF ( lcsh )
Environmental Engineering Sciences thesis (Ph. D.) ( lcsh )
Nuclear activation analysis ( lcsh )
Radioactive substances -- Florida ( lcsh )
City of Tampa ( local )
Genre:
bibliography ( marcgt )
non-fiction ( marcgt )

Notes

Thesis:
Thesis - University of Florida.
Bibliography:
Bibliography: l. 154-167.
General Note:
Manuscript copy.
General Note:
Vita.

Record Information

Source Institution:
University of Florida
Holding Location:
University of Florida
Rights Management:
Copyright [name of dissertation author]. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
Resource Identifier:
030111565 ( AlephBibNum )
11032170 ( OCLC )
ACH2329 ( NOTIS )

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Full Text









CESIUM-137 AND OTHER GAMMA
RADIOACTIVITY IN THE FLORIDA
ENVIRONMENT A STUDY OF
SELECTED MEDIA








CHARLES ERVIN ROESSLER











A DICSSRTATION PRESENTED TO~m THB GRDUATEa CDUNCL OF
THE UNIVERSITY OF FLORIDA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE! OF DOCTOR OF PHILOSOPHY









UNIVERSITY OF FLORIDA
December, 1967
























6 813,030

ROESSLER, Charles Ervin, 1934-
CESIUM6187 AND OTHER GAMMA RADIOACTIVITY
IN THE FLORIDA ENVIRONMENT A STUDY OF
SELECTED MEDIA.

The University of Florida, Ph.D., 1967
Health Sciences, public health


University Microfihns, Inc., Ann Arbor, Michigan










ACKNPOWLEDGMENTS


The author acknowledges with gratitude Dr. Billy G. Dunavant, the

chairmann of his supervisory committee, for direction, encouragement, and

invaluable assistance. He also acknowledges assistance of his committee

co-chairman, Dr. Herbert A. Bevis, especially for making many of the

financial arrangements which were necessary for sample procurement. He

wishes to acknowledge the other members of his committees, Dr. Hiarvey

L. Cromroy and Dr. John A. Wethington, Jr.

He especially wishes to thank Dr. E. G. Williams and others of the

Florida State Board of Health for their assistance and willingness to

provide pertinent data and information. Recognition also is given to

the radiological staff of various county health departments, to various

county agents, and to staff members of the Chemistry Division of the

Florida Department of Agriculture for their assistance in selecting and

locating sampling altes and in collecting samples.

He wishes to thank Dr. John E. Moore for making computer time

available and for providing some of the technical facilities necessary

for the diesertation study and Dr. A. 2. Palmer for hie assistance in

planning and conducting of beef sampling. Appreciation is aleo

extended to Dr. James Montelato for vegetable sampling advice, Mr.

Lawrence Fitzgerald for programming assistance, and Dr. John I. Thornby

for statistical advice.

The author also expresses his thanked to Mary Redrick for typing of

the final manuscript.








Finally, the author is deeply indebted to his wife, Genevieve, who

provided valuable assistance in nearly all phases of this project and he

wishes to acknowledge his children, Terry, Cindy, Mary, Francis, Kay,

and Jean, for their patience and occasional assistance during the

course of his graduate study.

The~ work was supported in part by United States Public Health

Service Training Grants No. 5-T1RH3-07(67) and No. 3-T1RH30-04S1(66).











TABLE OF CONTENTS


Page

ACKNOWLEDGMENTS .. .. ... ... .. .. .. .. . ii

LIST OF TABLES .. . .. .. .. ... .... * * vi

LIST OF FIGURES . .. ... . .. . * .* * ** viii

ABSTRACT ... .. ... .. .. .. ... . .. .. ix

CHAPTER

I. INTRODUCTION ... .. ... .. .. ... .. 1

II. REVIEW OF THlE LITERATURE . ... ... .. ... 4

Reviews of Environmental Radioactivity .. .. .. 8
Sources of Environmental Radioactivity .. .. ... 10
Ecology of Cesium-137 and Other Environmental
Radioactivity .. .. ... .. .. ... .. 11
Environmental Radioactivity Measurements in Florida . 32
Ceeium-137 and Ot her Radionuclides in Selected
Environmental Media--Mathodology and Findinge . .. 42

III. EXPERIMENTAL. APPROACH .. .. .. . .. .. .. .. 54

Selection of Media for this Study . ... ~. .. .. 54
Selection of Beef Sampling Stations .. . . ... 56
Beef Sampling ... .. . .. ... .. ... . 59
Vegetable Sampling .. .. .. . .. . ... 61
Sequence of Study . . ... . ... .. ... 63

IV. ANALYTICAL PROCEDURES AND EQUIPMENT . .. .. ... 66

Beef Sampling . .. .. .. ... .. .. 66
Vegetable Sampling . ... ... .. .... . .. 67
Beef Sample Preparation ,. ... .. .. . ... 68
Vegetable sample Preparation . .. ... . . .. 68
Gamma Radioactivity Counting . ... .. .. .. .. 71
Interpretation of Comma Spectra 72









Page

V. RESULTS OF BEEF SAMPLING .. ... ... .. .. 76

Ceeiurm-137 Content of Lean Meat from Grain-Fed Beef,
1967 . ... .. .. .. .. .. . . ... 77
Effect of Year of Collection .. . . ,. .. .. 81
Effect of Feeding Program and Meat Quality on Ceeium-
137 Levels . .. .. .. .. .. . . ... 82

VI. RESULTS OF VEGETABLE SAMPLING .. .. .. .. ... 85

Cesium-137 Content of Florida Vegetables--Average
Levels and Regional Variation .. .. ... .. 86
Effect of Year of Sampling on Ceaium-137 Levels in
Florida Vegetables .. ... ... .. .. .. 90
Cesium-137 Content of Florida Vegetablee--0ther
Observations ,. ... .. .. ... ... .. .. 92
Other Gamma-Emitting Radionuclides .. .. . .. 100

VII. DISCUSSION OF RESULTS . .. .. .. ... ... 103

Geographic Variation of Cesiumr-137 .. .. .. . 103
Other Variations in Ceeium-137 Levels . .. .. . 105
Magnitude of the Observed Ceeium-137 Levels . . 116
Influence of Observed Ceeium-137 Levels on Human
Intake and Exposure .. .. . . .. . .. 122
Possible Mechanisms and Factors Influencing
Cesium-137 Levels in Florida .. .. .. . 130
Other Radionuclides . .. .. . .. . .. 133
Discussion of Sources of Error . ... .. . .. 134
Further Investigations Suggested by the Results of
This Work .. .. .. .. ... .. .. .. .. 137

VIII. SUMMARY AND CONCLUSIONS ... . ... .. .. 143

Conclusions . . .. .. . .. .. . 146

APPENDICES . .. ... .. .. .. .. .,. . .. 48

A. EQUIPMENT AND INSTRUMENTATION . ... .. .. . 150

B, GAMMA-EMITTING RADIONUCLIDES IN THE CALIBRATION MATRIX 153

LIST OF REFERENCES ... ... .. . .. . . .. . 154

BIOGRAPHICAL SKETCH . .. .. ... . . .. . .. .. 168










LIST OF TABLES


Table Page

1. STRONTIUM-90O DEPOSITION IN THE UNITED STATES (MILLICURIES/
MILE2) 17

2. BEEF SAMPLING STATIONS ... .. .. .. .. .. .. .. 57

3. VEGETABLE SAMPLING .. ... ... .. ... .. .. 62

4. IDENTIFICATION OF VEGETABLE SAMPLING REGIONS AND STATIONS . 64

5. SUMMAKE OF CESIUM-137 CONTENT OF LEAN MEAT FROM GRAIN-FED
FLORIDA BEEF, 1967 .. . .. .. . .. .. 78

6. CESIUM-137 CONTENT OF LEAN MEAT FROM FLORIDA BEEF, 1967--
EFFECT OF GEOGRAPHIC LOCATION (EXPRESSED AS CESIUM-137/
POTASSIUMIRATIO) ................... .. 79

7. RANKING OF FIVE FLORIDA BEEF SAMPLING STATIONS ACCORDING TO
CESIUM-137/POTASSIUM RATIO OF LEAN MEAT .. .. .. .. 80

8. EFFECT OF YEAR OF COLLECTION ON CESIUE-137 CONTENT OF LEAM
MEAT FROM CRAIN-FED FLORIDA BEEF .. .. .. .. ... 81

9. VARIATION OF CESIUKI-137 CONTENT OF LEAN FLORIDA BEEF AS
INFLUENCED BY FEEDING PROGRAM AND GRADE OF MBAT .. .. 84

10. NUMBERS OF FLORIDA VEGETABLE SAMPLES ANALYZED FOR GAMMA
RADIOACTIVITY BY REGION, CATEGOKE, AND SAMPLING PERIOD . 86

11. CESIUM-137 CONTENT OF FLORIDA VEGETABLES--SUMMARY BY
SAMPLING PERIOD AND) REGION ... ... .. . ... 87

12. CESI1M-137 CONTENT OF FLOREDA VEGETABLES, 1967 SAMPLESS--
EFFECT OF GEOGRAPHIC LOCATION ... ... . . .. 89

13. RANKING OF FIVE FLORIDA VEGETABLE GROWING REGIONS ACCORDING
TO CBSIIUK-137 CONTENT, 1967 SAMPLES . .. .. .. 89

14. COMPARISON OF CESIUM-137 LEVELS IN FLORIDA VEGETABLES--
1966 AND 1967 SAMPLING PERIODS . ... .. .. . ... 91

15. AVERAGE CESIUM-137 CONTENT OF FLORIDA VEGCETABLES--SUNFARY BY
CATEGORY, REGION, AND YBAR OF SAMPLING .. .. ... 93








Table


Page


16. RANGES OF CESIUM-137 CONTENT IN FLORIDA VEGETABLES
SUMMARIZED BY REGION, CATEGORY, AND SURVEY PERIOD .. .. 94

17. CESiUM-137 LEVELS IN FLORIDA VEGETABLES, HIGH INDIVIDUAL
SAMPLES .. .. .. .. .. .. .... . .. ... 100

18. CESIUM-137 LEVELS REPORTED IN BEEF AND OTHER MEAT BY VARIOUS
INVESTIGATORS .. .. . .. .. ..... . .. . .. 106

19, CESIUK~-137 LEVELS REPORTED IN VEGETABLES BY VARIOUS
INVESTIGATORS .. .. .. .. .. .. .. .. 111

20. FLORIDA VEGETABLE SAMPLES WITH R'IGREST CESIUM-137 LEVELS, DRY
HEIRT BASIS ................... .... 121

21. CESIUM 137 INTAKCE ESTIMATED FROM PUBLISHED VALUES .. .. 123

22. CESIUN-137 ENTAK(E ESTIMATE FDR THREE FLORIDA CASES,
1966-1967 .. ... .. .. .. .. .. .. .. .. 125

23. REPORTED BODY BURDENS 07 CESIUM-137 . .. .. . .. .. 128

24. EQUIPMENT AND INSTRUMENITATION . ... ... .. .. .. 150

25. GAMMA-EMITTING RADIONUCLIDES INCLUDED IN THE CALIBRATION
MATRIX............. ............ 153










LIST OF FIGURES


Figure Page

1. CESIUM-137 AND STRONTIUM-90 IN PASTEURIZED MILK--
COMPARISON OF THE FLORIDA STATION TO NATIONAL
AVERAGES AND RANGES .. . . . . .. . 5

2. RADIONUICLIDES INI FLORIDA MILK--TEARLY AVERAGES BY REGION . 7

3. CURRENT SAMPLING PROGRAMS IN FLORIDA FOR ENVIRONMENTAL
RADIOACTIVITY ANALYSIS ... .. .. .. .. .. .. 40

4. BEEF SAMPLING STATIONS .... .. .. .. .. 58

5. VEGETABLE SAMPLING REGIONS AND STATIONS . . .. .. 65

6. CESIUM-137 CONTENT OF LEAN MEAT FROM GRAIN-FED FLORIDA BEEF--
1967 .. ... .. .. .. .. . ... . .. 77

7. CESIUM-137 IN FLORIDA VEGETABLES ACCORDING TO SAMPLING PERIOD
AND REGION .............,,..., ,... 87

8. CESIU>-137 IN FLORIDA VEGETABLES, CLASSIFIED BY SAMPLING
STATIONS WITHIN CATEGORIES, 1966 AND 1967 . .. .. .. 96

9. CEISIUM-137 IN FLORIDA VEGETABLES, CLASSIFIED BY REGIONS
WITRIN CROPS, 1966 AND) 1967 . ... . .. ... .. 98

10. CESIUM-137 IN FLORIDA VEGETABLES, CLASSIFIED BY CROPS WEERIN
REGIONS, 1966 AND 1967 .. ... ... .. .. .. 99

11. GEOGRAPHIC VARIATION OF CESIUM-137 INI FLORIDA MILK, BEEF, ANID
VEGETABLES ....................... 104








Abstract of Dissertation Presented to the Graduate Council
in Partial Fulfillment of the Requirements for the
Degree of Doctor of Philosophy

CESIUM-137 AND OTHER GAMMA RADIOACTIVITY IN THE FLORIDA ENVIRONMaN' --
A STUDY OF SELECTED MEDIA

By

Charles Ervin Roesaler

December, 1967


Chairman: Billy G. Dunavant, Ph.D.
Co-Chairmant H. A. Bevis, Ph.D.
Major Department: Bicenvironmental Engineering


A study was performed of the kinds, level, and distribution of

galmma-emitting radionuclides in the Florida environment. The investiga-

tion was initiated because of the unuenal levels and characteristic

geographical patterns of casium~-137 (137Ca) found in Florida milk and

forage in earlier studies. Beef and vegetables were selected as the

most important media for sampling.

Sampling was carried out in May and June, 1966, and during January

through July, 1967. Analyses were performed by gamma spectroscopy on

triturated whole sample. Complex gamrma spectra were interpreted in

terms of the individual contributing components by use of the simultaneous

equations method.

The most signaificant gamma-emitting radionuclide present was 137Ca

and the evaluation of the data was concentrated on this nuclide.

Levels of 13Ca in.both beef and vegetables abowed geographical

patterns of variation similar to those reported earlier by others in

Florida milk. Maximum~ level were found in the central and southern

parts of the State, with intermediate levels in the northeastern and








north central parts of the State, and the lowest levels in the northwestern

part of the State. In addition, vegetable samples showed a marked differ-

ence from southeast to southwest, with average level in the southeastern

part of the State as low as in the northwestern part.

The levels of 1370 in lower-quality meat from animal that had fed

primarily on grass were much higher than those in high-quality meet from

feed-lot animals. These levels were higher than any other level reported

in beef in the conterminous United Statee.

There was no apparent difference in 1370 concentrations between

leafy, fruit, and root categories of vegetables; although certain crope

in each category did exhibit consistently higher levels than the other

crop in the same category.

Ceeium-137 concentrations found in this study were compared to

literature values, both to those reported for year previous to this

study and to 1966-1967 value obtained by extrapolating published values

to that time. Ceeium-137 concentrations in both beef and vegetables in

much of the State were considerably higher than the estimated national

averages for the same period; average concentrations in the regionE

exhibiting the lowest average levels were found to be comparable to the

estimated national averages.

The significance of the observed 13Ca level was evaluated in terms

of the human intake of this nuclide. It was estimated that radioactivity

intakes from locally produced food in Northwestern Florida would be

similar to the national average. Three hypothetical case of assumed

diet composition and source of food.vere set up to evaluate levels in the

remainder of the State. Consideration of diet with various combinations








of Florida milk, beef, and vegetables having the average levels shown

in much of the State resulted in predicted 137s intakes and bddy burdened

ranging from two to 20 times the projected national average. The intakes,

body burdens, and resulting whole-body radiation dose estimated for the

various case considered were all less than the applicable radiation

protection guides, but the guides could be approached by individuals

constantly consuming food at the extreme levels found.

It was concluded that unusual environmental factors or mechanisms

are involved in the levels of 1370 found in the Florida environment.

The possibility of such mechanisms has important implications to waste

disposal, hazard evaluation, and nuclear facility operation. The

mechanisms were not identified but there is increasing evidence that the

role of uptake from the soil is greater than that reported for most areas

of the country.










CHAPTER I

INTRODUCTION


This research involved a study of the kinds, levels, and distribu-

tion of gamma-emitting radionuclides in selected segments of the Florida

environment with emphasis placed on the nuclide cesiurm-137 (1370s) in

animal and vegetable products.

This study was initiated because of unusual levels and characteris-

tic geographical patterns of 1370s found in Florida milk and forage in

earlier studies described in Chapter II. Milk monitoring program of

the United States Publie Health Service (USPRS) and of the Florida State

Board of Health have indicated that the average levels of 137Ce in milk

in much of Florida have been higher than the national average and among

the highest in the nation for a number of years, while strontium-90

(90Sr) levels have been consistently average or below. Further investiga-

tions have shown a consistent geographical pattern within the Btatep aid

it appears that these levels are primarily related to the intake of

1370s by cows through the medium of locally grown forage.

The major effort in this study was directed toward determining the

extent to which these unusual patterns of 1370s are reflected in other

elements of the human food chain, particularly lean beef and truck

vegetables.

In addition, measurements were made of other gamrma-emitting radio-

nuclides in all eamples.











Significance of this Research

First, it is important to the welfare of the people of Flazida that

the extent to which persons in the State are exposed to radiation from

all sources and by all routes be known.

This study contributes to this knowledge by (1) investigating the

extent to which the elevated levels of 13Cs previonely observed in milk

and forage extend to other media, particularly other elements of man's

food chain, (2) determining whether other gamma-emitting radionnelides

show elevated levels in Florida, and (3) evaluating the potential

influence of these nuclides and their levels on man's radiation exposure.

In Chapter II, it is pointed out that many route of radiation

exposure have been and are being evaluated in Florida. Gross alpha and

beta radioactivity levels are measured in a variety of media in this

state. Detailed studies have been performed in selected localities, and

exposure to specific nuclides through the route of milk is being studied

in great detail. However, this work represents the first extensive,

statewide study of exposure to specific nuclides through food chain

elements other than milk.

Second, the information developed here to estimate exposure levels

should also contribute to the underatending of the mechanisms involved in

the previously mentioned unusual levels of 1370 in Florida.

It also is important to predict and evaluate the impact on the

environment--and, eventually, on human health--of nuclear activities such

as the operations of nuclear power plants, nuclear laboratories, and

nuclear powered vehicles. A thorough, systematic study of radioactivity

in the State provide a baseline of radioactivity levels ~against which

any future increased can be compared. This means determining not only




















average levels of various radionaclidae for the purposes of comparison

but also normal variations of these level for use both in designing

future surveys and in determining whether apparent increased are signifi-

cant. In addition, knowledge of the mechanisms and rates of transfer

of radionuclides through the environment provides a baste for predicting

the consequences of accidental released of radioactivity. At the same

time, since intentional waste release is governed by criteria based on

various assumptions concerning the normal behavior of radionuclides in

the environment, it is important to be aware of any unusual behavior such

as suggested by the Florida milk 1370s levels.

Finally, this study is significant in that the data collected will

contribute to other environmental radioactivity study efforts in the

State. For example, these data can be need to complement the study of

13708 in Florida milk being carried out by the Florida State Board of

Health -and to serve as an extension to the environmental monitoring being

carried out in the Cape Kennedy off-site socio-economic impact area by

the United States Air Force, the USPaIs, and the Florida State Board of

Health.









CHAPTER II

REVIEW OF TRE LITERATURE


This study was undertaken as a direct result of the findings of

earlier studies of radioactivity in Florida milk and dairy feeds carried

out by thin author and other. The USPHS began a program of sampling

raw milk for radioactivity analysis in 1957,and out of these initial

effort grew the present USPRS Pasteurized Milk Network which has 63

stations, at least one in every state of the Union, the Canal Zone, and

Puerto Rico.- A station representing Florida became operative at Tampa

during August, 1960. In this network, a composite sample ie taken from

the pasteurized milk marketed in the community and shipped to a USPHS

laboratory for radionuclide analysis.

Average monthly 1370s and 90Sr levels at the Florida station of the

network are compared against the corresponding national ranges and

averages for the period 1961 through February, 1967, in Figure 1.

Consistently, the average levels of 137Ca at the Florida station of thief

network have been well above the national average; aince mid-1964, they

have been the highest in the sampling network. In contract, 90Sr levels

have not been particularly high; with the exception of two months, they

were consistently below the national average. As a result, the 137Ce/90Sr

ratios have been particularly high.

Workers at the Florida State Board of Helalth initiated a program

in 1961 for the statewide collection and regional compositing of raw

milk from a 10 per cent random ample of the dairy farms in the state.2-

















CESIUM-137 $



~200




100





1961 -1196) "g 'l'gs4 1"bs 48





SSTRONTIUM-90

S50




25








FIGURE 1. CESIUM-137 AND STRONTIUM-9 IN PASTEURIZED MILK(--COEMPARISON
OF THUE FLORIDA STATION TOG NATIONAL~ AVERAGES AND RANGESL











Figure 2 summarizes 137Ca ad 90Sr result for 1963 through 1966.

It shows that the average results reported for pasteurized milk samples

from the Tampa station of the national network are comparable to the

average results for composite raw samples collected from the same general

region. The figure also shows that the Tampa station results for both

nuclidae are reasonably well representative of the reported average of

all milk produced in Florida, particularly the area east and south of

Tallahassee. There does appear to be a gradual transition from lower

137Ca levels in the northwestern part of the State to higher levels in

the eastern, central, and southern parts of the State with the highest in

the central part of the State.

Figure 2 also showe that 137Ca levels in the northwestern part of

the State are below the .State average. These levels fall more rapidly

with time than levels in the remainder of the State and fall from above

the national network average in 1963 through 1965 to below it in 1966.

Statewide average 90Sr results are consistently below the national network

average and remain fairly constant for the eastern, central, and southern

parts of the State. These results show a greater fluctuation in the

Northwest--even rising above the national network average in 1965 and

1966.

Porter et al., in a special etudy of the Tampa milkshed during

October, 1963, through February, 1964, observed considerable farm-to-farm

variation within that area and concluded that the elevated milk levels

were due to elevated levels of 137Ca intake by the animals and not to

unusual transfer of the nuclide from the feed to the milk.' They also

identified pangolagrass (Diaitaria dechaboen) as the principal contributor

to the high 137C intake.









-*-Tampa Station National Network
S" National Network Average
*** State Average


CESIUM-137


~200


;10


FIGURE 2. RADIONUCLIDES IN FLORIDA MILER--TBARLY AVERAGES BY REGION


i mm,










In 1964, Roeasler and Williame Initiated a study to investigate more

fully the factor influencing radionnelide levels in Florida milr.9

Unpublished reports of their work also show a high farm-to-farm variabili-

ty in milk radionuclide levels. These results enggest that when examining

more farms on a wider geographic basis, equally high or higher intakes

can be attributed to forages other than pangolagrass.7l

Reviews of Environmental Radioactivity

The interest in environmental radioactivity since the early 1950's

is evidenced by the large number of bibliographies, hearings, symposia,

conferences, and books devoted to the subject.

Hoard, Eisenbud, and Harley prepared an extensive bibliography on

radioactive fallout in 1956.10 Because of growing public concern at this

time about the possible effects of fallout from nuclear weapons testing,

the Joint Comrmittee on Atomic Energy of the Congress of the United States

held hearings on radioactive fallout and its effects on man in 1957, and

again in 1959,1,1 The scientific community explored the question of

radioisotopes in the biosphere in a symposium in 1959 and again in the

First National Symposium on Radioecology in 1961.131 The United States

Atomic Energy Commission (USAEC) sponsored a conference on radioactive

fallout from nuclear weapons teast in 1961 and again in 1964.151

Eisenbud authored a text on environmental radioactivity in 1963, and

a collection of paper reviewing the ecology of radioactive fallout, soils,

plants, foods, and man, edited by Fowler, vae published in 1965.171

Natural environmental radioactivity was the subject of a symposium

in 1964 and a 2,000 reference bibliography by Klement in 1965.192

The proceedings of a symposium on radiation and terrestrial eco-

systame in 1965, edited by Hungate, review radioactive fallout phenomena










and mechanisms, primordial and cosmic-ray produced radionuclides, soil-

plant relationship, and radionnelide cycling as well as present results.

of individual research.2 The Second National Symposiurm on Radioecology

was held in 1967, at which time emphasia was placed on reporting .

individual investigations of both effects of radiation on the environment

and behavior of radionuclides in the environment.22

Comar reviewed the literature up to January, 1965, relating to the

movement of fallout radionuclides through the biosphere and man; Ellia

reviewed and appraised the level and biological significance of current

fallout levels in the United Kingdorm in 1965.232 The fallout pattern

in the Nordic countries was a topic at a proceedings of the First Nordic

Radiation Protection Conference in Sweden in 1966.25 About the same time

Leistner, on behalf of Euratom, reviewed the reported research on the

radioactive contamination of foods of animal origin, tabulating reported

distributions, retention, and ambient levels.26

A book edited by Russell in 1966 is devoted entirely to radioactivity

and human diet.27

In August, 1959, the President of the United States directed the

Secretary of Health, Education, and Welfare to collate, analyze, and

interpret data on environmental radiation levels. This assignment result-

ed in the appearance in April, 1960, of the publication, Radiological

Health Data (subsequently changed to Radiological health Data and

ESRepot)* This monthly publication contained regular reports of routine

national and worldwide monitoring programs operated by ~agencies of the

United States as well as frequent special reports of state monitoring

programs, special studies, special evaluation of particular problems, and

topical revieve of current research.28










Sourterr of 'Environlmental Radioactivity

According to the best present knowledge, man has always been exposed

to varying degrees of natural background radiation from cosmic radiation

and from naturally occurring radionnelides.

Eisenbud points out that the world inventory of radioactive materials

prior to World War II, both in the environment and in the laboratory, was

confined to those which occurred in nature, with the exception of a

relatively few millieuries of radioactivity produced in cyclotrone during

the late 1930's.17 Construction of large nuclear reactors during the war

and the associated operations for extracting plutoniumn from irradiated

uranium resulted in the first extensive occasions for contaminating the

environment with radioactive substances. Then, in the late 1940's and

continuing at an accelerated rate throughout the 1950's, there began a

series of nuclear weapons teste that resulted in a worldwide distribution

of radioactive materials in all segments of the environment--the atmos-

phere, the soil, food chain, and man himself.

Eisenbud liste the principal sources of environmental radioactivity

as natural radioactivity, preparation of nuclear fuel through the stages

of mining, concentrating, milling and fabrication, reactor operations and

accidents, conventional radioisotope nee, aerospace applications of

radioisotopes and reactors, fuel reprocessing and radioactive waste

disposal.17 Comar identifies the major source to date as radioactive

debris from the testing of nuclear weapons.23 On the other hand,

important future sources will likely be nuclear reactor operation, radio-

isotope use, and radioactive waste disposal.

Williame ejiJE. pointed out that varying levels of natural radio-

activity do occur in Florida and that these materials do have an










opportunity to become relocated in the environment through the operations

of phosphate mining, phosphate fertilizer production, and subsequent use

of the by-products.29 With regard to the other sources of environmental

radioactivity just mentioned, there is no uraniurm mining, concentrating,

or milling, nor fuel fabricating or reprocessing, nor large acale or

Commercial radioactive waste disposal in the State. Reactors are presently

limited to the University of F1orida Training Reactor, and there have

been no reported contaminating incidents in the State.

The Pinellas Peninsular Pleat of the USAEC is located near St.

Petereburg, Florida, but from the regular published reports of the

contractor's environmental monitoring in the vicinity, it may be inferred

that radionuclides potentially reaching the environment from this plant

are limited to tritium.30 This meman that, with this exception, at the

present time any widespread radioactivity in the Florida environment auet

be naturally, occurring radioactivity or must Come from fallout

injected into the atmosphere. At the same time, the environmental

mechanisms affecting activity from these sources will affect in much the

same manner any future radioactivity from local contamination sources.

With regard to the future, several nuclear power plants are

definitely planned for the State of Florida and it is likely that radio-

isotope or reactor powered electrical generators or propulsion devices

will be used in future vehicles launched from the missile testing and

space flight complex at Cape Kennedy.3

:Ecology of Ceeium-137 and Other Environmental Radioactivity

It was pointed out in the preceding section that, with certain

local exceptions, the major source to date of environmental radioactivity

is radioactive fallout from the nuclear weapons testing. Ceeium-137 and










90Sr are considered biologically to be the most important radionuclides

in long-range fallout because of their long physical half-lives, the high

yield of these nuclidea in fission, and their respective chemical

similarities to the natural body constituents, potassiumn and calcium.233

Indeed, the majority of studies of special nuclides in the environment

appear to be concerned with these two nuclidea.

The remaining examination of the literature emphasizes 13Cs, but

gives attention to other nuclides to the extent that they might also

appear in samples examined for 137s..
In 1959, Langham and Anderson reviewed biosphetic contamination from
137
Cs. They estimated production by weapons tests and deposition up to

that time, reported important exposure routes to man, and listed an

extensive bibliography.33 They proposed expression of 1370s levels as

13Cs per grea of potassium because of the metabolic similarity of cesium

and potassium. A later exhaustive review of cesium ecology was made by
Davis in 1963.34

In 1965, Comar summarized and updated this information in a concise,

yet comprehensive, review of~ the movement of fallout nuclides through the

biosphere.23 He observes that cesium and potassium are chemically

similar. However, since they are not metabolically interdependent, the

137Ce/potassium ratio is not as meaningful as the 9Sr/calcium ratio.

Nevertheless, 1370 concentrations are often expressed relative to

poasesium for two reaason: (1) naturally radioactive potassium-40 ( OK)
and 1370s ae often measured simultaneously by gamrma spectrometry, with

401 thereby serving as an internal standard, and (2) in man, the cesium/

potassium ratio correlates better with lean body seass and hence with

radiation dose than does the 1370 per kilogram (kg) of body eight.










The worldwide deposition of 1370 is usually estimated by applying

a17 s90r ratio to the values of deposition of 90r since it has been

studied more extensively. The 137C 790Sr ration vary between 1.0 and

3.0 as these nuclides are produced, but this ratio will change markedly

as the two elements pass through metabolic systems.

Radionuclide pathways to man

Fallout radionnelides reach man primarily through plants, either by

his consumption of foods of plant origin or indirectly by his consumption

of animal products.3

Plants become contaminated by radioactive materials from the atmos-

phere by either (1) indirect contamination which occurs when radioactive

materials enter the soil and passes into the plant through the roots as

do soil nutrients or (2) direct contamination in which the material is

deposited on some portion of the plant and passage through the soil is by-

passed.23 Direct contamination reflects events of the recent past, varies

with the rate of deposition, and is designated "rate dependent." Indirect

contamination is governed by the total amount available in the soil and is

designated "cumulative dependent." Indirect contamination has the

characteristics that (1) material deposited before the plant develops can

still enter the plant, (2) short-lived radionuclides that enter the soil

will, have a high probability of decaying to insignificant levels before

reaching the plant roots, and (3) radioactive substances entering the

soil mlay be diluted with soil substances, rendered unavailable to plants

by -fixation to soil materials, or discriminated against in plant uptake.

The concepts of cumulative and rate dependent contributions to radio-

nuclide levels in an environmental component are illustrated in the

generalized expression:











C = Pd d + rFr


where C = concentration of the radionaclide in the sample
on interest,

Fd = cumulative deposition,

PC = current rate of deposition,

and pd and pr are the proportionality factors for cumulative deposition
and deposition rate, respectively, for the particular system and nuclide

under consideration.3356

Once radionaclides are deposited on or incorporated into plants, the

grazing animal effectively collectB CDntaminatioR fTOm plant material and

concentrates it in animal products; however various factors such as

metabolic behavior of the specific nuclide and animal feeding and manage-

ment practices influence the relationship between the amount deposited

in tissues or transferred to secretions that are used for food.23

In order to select important media for further study and to consider

possible movements of radionuclides in the Florida environment and

possible geographic, media, and temporal variations, it is necessary to

review briefly what is known about the passage of radianuclides, particu-

larly 137s, through various segments of the environment.

Origin, transport, and deposition of radioactive fallout

Klement and Langham both reviewed fallout phenomena and mechanisms

in 1965.363 Klement identified the sources of injection of radio-

activity into the atmosphere as nuclear weapons teete, peaceful nuclear

explosives tests or utilization, reactor operations, and space applications

of nuclear energy. He placed weapons tests foremost from the standpoint

of widespread environmental radioactivity. The radioactivity can include

fission products (over 200 different nuclidea of about 36 elements between











atomic numbers 28 and 65) and activation products that come about as a

result of neutron interaction with soil, air, water, or parts of the

nuclear device at the time of the detonation. Radioactive debris is

usually apportioned into three fractions: (1) fallout in the immediate

vicinity, (2) material injected into the troposphere, and (3) material

injected into the stratosphere.

Local fallout is not a concern in this Florida study, but tropospher-

ic fallout can deposit short-lived nuclides in the weeks immediately

following atmospheric weapons tests. Deposition from tropospheric contamil

nation is governed by tropospheric air flow and should be highest at the

latitude of injection with a certain amount of dispersion and displace-

ment and with local low altitude variations due to terrain such as

mountains and land-water contrasts.173 One exception is the downward

and equatorward movement along isoentropic surfaces of debris injected

into the upper polar troposphere. A second exception is the poleward

movement and sinking in subtropical regions of mid- and upper-tropospheric

injections in equatorial regions.

Material injected into the stratosphere may remain there from several

months.to several years and provides the source of long-lived materials

currently being deposited on a worldwide basis. Stratospheric materials

are transferred to the troposphere, from which deposition is primarily

due to precipintiato with a small increment due to dry deposition.36

List et al. described the generalized worldwide deposition of 9Sr up

to late 1963.3 The mean latitudinal distribution in the Northern

Rlemisphere showed a very low deposition in the vicinity of the north polar

region, a rapid increase to a maximum between 40. and 50. N, and then a

gradual decrease in the vicinity of the equator. Davie prepared a similar










latitudinal deposition curve for average 1370 content of precipitation

for 1955-1958.3 Florida lies between 25. and 31. N, a location whose

deposition on the mean distribution curve lies midway. between the

Northern Hemaisphere peak and the equatorial minimum. Within latitude

bands, differences in rainfall sad possibly other meterological phenomena

canae variations in deposition. It has been suggested that fallout over

ocean might be higher than over land but List et al. report that comparison

of soil from eites with maritime exposure to soil with sites from continen-

tal exposure shows no systematic difference either in total deposition or

in amount of 908r deposited per inch of rainfall.37

Two major techniques have been employed for the direct quantitative

assessment of fallout deposition on the earth's surface: (1) deposition

sampling (dry and precipitation) and (2) soil sampling. Based on soil

sampling in 1963-1964, maps of 90Sr deposition were prepared for the

world and for the United States. The latter shows Florida lying between

the 100-millicurie per square mile contour at the southern tip of the

State and the 125-millieurie per square mile contour along the northern

border.3

Stratospheric deposition is neually described by a simple exponential

function; howeverMachta has described shortcomings of such a simplified

model .38 Comar quotes an overall mean stratospheric residence time of

two years, while data presented by Klement imply a value of one year.233

As an aid to predicting general fallout levels, the Federal Radiation

Council divides the United States into "wet" and "dry" areas depending

upon average annual rainfall (roughly separated by the 20-inch rainfall

isoline).394 It further denotes an intermediate area with lightly less

than 20 inches of annual rainfall and, by superimposing the latitudinal









effect on the precipitation effect, assigns most of the State of Florida

to another imrmediate area with "an expected lesser fallout compared with

the 'wet' eastern United States because of its subtropical location."

Estimates of 9Sr deposition in the United States through 1966,

derived from several sources, are shown in Table 1. Values for years

beyond 1966 can be obtained by an extrapolation based on the assumptions

that deposition is described by a single exponential function and that

there will be no signifiesnt additions to the stratospheric content.


TABLE 1

STRONTIUM-90 DEPOSITION IN THE UNITED STATES
(MILICURIES/MELE2)



Increment Accumulated
Wat Area Dry Area Net Area Dry Area

Based on Federal Radiation Council Report No. 6:40

1963 - 150 65

1964 30 12 180 77

1965 15 6 195 83

Total after 1965 25 10 220 93

1966 estimate36 7.5 3 203 86


Although air is the medium by which fallout is delivered to terree-

trial environment, Klement emphasized that it is difficult to obtain

explainable relationships between concentrations in surface air and other

environmental media each as pr~eipitation, soil, sad biological systems.36

Some qualitative information is being developed; for example, Pelletter,

Whipple, and Wedlick have attempted empirically to fit measurements in

the Lake Erie area with a model of the form:











D t H(a-a-br)
CA

where D = deposition, picocuries per square meter, (pCi/m2)
3'
CA = air concentration, pCi/m
H = height of fall constant, m,

a = dimensionless factor to account for dry deposition
into the precipitation collector,

b = elimination constant, (inches of rain)-1, and

r = rainfall amount, inlches.41

Further study is necessary before the various relationships can be clearly

defined. Air concentrations and deposition rates show a peak during

the spring of~ each year which is related to entrance of debris from the

stratosphere during late winter, spring, or early summer. After new

tropospheric injections, peaks in concentrations are seen along the path

of the cloud, and air measurements are particularly useful to determine

arrival time of new debris at specific locations and thus anticipate the

rise in levels in other media. Atmospheric contamination of fallout

1370 is not considered an inhalation hazard.3

Radionuclidea in water

In his 1965 review, Klement also summnarized some of the observations

of fallout radionuclides in water reported up to that time.36 He stated

that short-term variations in deposition are probably not as detectable

in fresh surface waters as they are in surface air, but that the same

seasonal variations are seen. Relative concentrations of nuclidea in

surface water vary with local deposition rates and characteristics of

the local aquatic environment. Large differences can be expected within

a major river or lake because of runoff and flow.











Langham and Anderson concluded that drinking water contarmination

with fallout 1370 does not constitute a health hazard.3 However, water

may have an importance in the food chain in that 13Ca is more available

to organisms living in aquatic environments than in terrestrial

environments.42

Cesium-137 and other radionuclides in the soil

Schulz reviewed soil chemistry in 1965.3 He listed fission

products likely to be found in the soil, classified elements according

to their mobility in the soil, and discussed the use of soil chemistry

in predicting. plant uptake of radionuclides.

Cumurlative levels of radionnelides in the soil and their distribution

in depth, important factor in plant uptake from the soil, are affected

by weathering and other disturbing influences.36 In most soils in the

United States, 90Sr does not appear to leach very rapidly (supporting

the validity of soil sampling as a means of determining accumulated

fallout deposition). Virtually all of the nuclide is found in the upper

8 inches of these soils. In medium to fine textured soils, about 75 to

80 per cent of the deposited 90Sr is found in the upper 2 inches and

even in medium textured soiled similar proportions are found in the upper

4 inches.

A number of author have cited the fact that cesium is readily

retained by soils.343,34 Its sorption is characterized by high

adsorption onto mineral particles (the ion exchange properties of soil

being largely associated with clay minerals in the soil complex), but

there is a certain amount of disagreement over the mechanism of this

fixation. Nearly all of the 1370 is found near the surface (the top

2.5 centimatera) of undisturbed soiled in the United States.343










Downward movement of cesium in undisturbed soiled is even less than

strontium. After five year, 50 to 80 per cent of added 13Ca remained

in the upper 5 centimeters with little penetration below 10 centimeters.23

It is pertinent to the Florida soil ecene that, in batch experimental,

sandy loans and clays absorbed 90 per cent of the available cashum,
while sand absorbed only 50 per cent.34

Ranges of ph commonly encountered have little effect on cesium

sorption since it is approximately constant above a value of 3.5 (though
decreasing rapidly below p 3.5).3

While easium is desorbed by cations of neutral ealts, more readily

by K+ than by Na+ or Ca +, it effectively compete with potassium in
interactions in the soil.3 Trace amounts of cesium adeorbed by the soil

are held more strongly than strontium. Russell etatee that the extent of
137
Cs fixation in soil depends upon the clay content and is inversely

related to the organic matter in which ceeiumr remained less strongly

bound.3 Schulz states the chelation of nuclides by soil organic matter

may cause them to keep some mobility in the soil.43

Complementary ions have a strong influence on the redistribution of

nuclides in the soil profile.43 For example, it is expected that the

amount of soluble calcium will have a direct effect on the mobility of

Srfl and RaC in soils and consequently on the eaee of uptake by plants.

Alk~ali cations present a more complicated case.) With regard to
137
Cs, complementary tone can be classed into two group: (1) those
having little effect on ceeiurm, oneh as dilute If the alkali cation Na ,

and the alkaline earth Ca >@;**, and Ba+ which solubilize or release

Lase than 10 per cent of added carrier-free 13Cs and (2) those liberating

moderate amounts of bound ceeiumr, such as Ce NRq K ~, and Rb which











free 20 to 80 per cent of the cesium to a labile form, Typical agricul-
++ ++I
tural soil in the neutral pR range possesses primarily Ca and Mlg as

labile ions. These have little effect in releasing added 1370 for

plant uptake.

Movement of cash~m-137 and other radionaclidea from the soil to plants

A number of experiments in nutrient solution indicate that cations

apparently compete against cseium in uptake by plant rooted. In one =

experiment at low external centum concentrations, potaeeina, rubidium,

emrmonia, and cesiumn were markedly effective in depressing 1370 uptake by

barley roots, while sodium, lithium, calcium, and magnesium were not; at

high concentrations, all inhibited 13Co absorption. Millet, oats, buck-

wheat, sweet clover, and sunflower discriminated slightly against rubidium

and strongly against ceeium in favor of potassium. In another experiment,

ani incraeae in the potassiumn of the solution decreased 137Ca uptake by

bean' plants but resulted in an increased potaeeiurm content of the plants.

At low potassium levels, barley showed high selectivity for potassium

relative to cesium; ~however at high concentrations, uptake was lees

selective' in favor of potaesium. On the other hand, other investigators

reported that adding potassium had only a mall effect--a 100-fold increase

in potassiurm reduced 1370 uptake by only a factor of two and non-

radioactive cesium enhanced 137Ca urptakre.45

Uptake by plants from soil is influenced by both the availability

of the element in the soil and the inherent behavior of the plant with

regard to available elements. According to Mensel, plant concentrations

Sof various radioactive elements, after they have been added to the soil

in water-soluble formsB, may be several orders of magnitude higher ~or

lower than the Concentration in the soil. He classifies elements into










five classes of uptake, ranging from strongly concentrated to strongly

excluded by assuming that the behavior of radioactive elements in the

soil-plant system is identical with that of stable nuclides of the same

element. In general, those nuclidea that are most readily absorbed are

soluble in the soil or are isotopic with elements that have metabolic

functions in the plant. Conversely, those that are least absorbed are .

quite insoluble in the soil. Notable examples are strontiurm, lightly

concentrated; radium, not concentrated; and easium, lightly excluded

in uptake from the soil.

Removal of 1370 from the soil is inhibited by the strong fixation

in the soil but uptake varies with soil type.2343

In typical soils of the temperate regions, 1370 was taken up about

one-tenth as much as 90Sr, with this ratio decreasing with time to about

one twenty-fifth or less after about three years.23 This sugg~ets more

than one cesiumn storage compartment in the soil. Lees strong binding in

organic matter has already been mentioned, and observations suggest that

a high level of organic matter in the upper layer of some permanent

pastures might reduce binding of cesium by clays, thereby enhancing and

extending its availability to plant rooted to one or two yeare.233 In

certain tropical arene Ca was found to be more available to plants

than had been expected.23

Schulz reasons that complementary ions, in strongly affecting

mobility of ions in the soil as outlined in the preceding section, will

in turn influence uptake by plants. In modern agriculture, nitrogen,

potassium, and phosphorus are commonly added to soils. From the

complementary ion effect, it would be expected that addition in the forms

K+ and NR{+ would liberate considerable amounts of 137Ca into a labile










form for subsequent plant uptake,.while the application of nitrogen in

the 803~ form would have little effect on the fixed Co. In an

erelen ySfUE bt + sa 1+ 137
exprimnt y chuz, ot K nd R4increased the Co uptake by

romaine lettuce but the NH{+ had a much greater effect, than K This

was explained by the hypothesis that after the NH4hdreesd ie

1370, apicrobial oxidation of the oxcess N1 oN3~rmvd tfo

competition with the now labile 13Ca for plant uptake.

Davia agrees that uptake of Ca from the soil is increased by the

addition of cesium and cites this as evidence that the capacity to fix

cesium in the unavailable form is actually very small. He cites a

number of experiments, however, where the uptake of Ca by lettuce,

greas, alfalfa, corn, millet, and wild plante was decreased by the

addition of potassiumr or was inversely related to the exchangeable level

present. In another experiment, added potassium resulted in a decrease

in the 1370 uptake by Ladino clover and, as a corollary, the uptake

increased as soil potassium was reduced by continued cropping.5 In this

latter experiment, stable cesium added to the soil, even to toxic levels,

caused increased 1370 uptake in this crop.

The collected evidence from the studies cited in this section seems

to indicate that complementary ions play a role in releasing fixed cesium

from the soil, and that stable cesium added to the soil enhances the

overall uptake of Co by plants, but that the effect of stable cesiurm

on plant uptake from available 137s and the effect of potassium on the

uptake from the soil are not clearly understood.

The effect of soil moisture content is apparently not clear. In

studies with beans in soil, limited soil moisture resulted in greater

1370s uptake than writh ample moisture.45 On the other hand, Pendleton











speculated in 1962 and ~again in 1967 that because of the high availability

of the nuclide to aquatic and emergent plants, milk and meat from grazing

animals utilizing forage from wetlands may contain much more of the

nuclide from fallout than such products from drylands, and that the

geographic variations observed in 13Cs content of ailk may be, in part,

a result of different levels of uptake by plants of vet sad dry lands.424

Behavior of ceeium-137 and other radionuclides in plante

Ceeiurm and potassium follow similar paths in physiological processes

but are not used in an equally competitive manner by plants.3 Trans-

location of cesium is more rapid than that of other fiesian products.

Tissue distribution of this element varies with species. When available

during active vegetative growth, it goes to the leaves and flowers with

smaller amounts going to the seeds. Accumulation of 13Ca by plants under

natural conditions varies considerably among apecies and with environ-

mental conditions.

In 1959, Langham and Anderson speculated that 13Ca was entering the

biosphere via direct contamination of the vegetation rather than via

soil contamination and plant uptake.3 It was soon determined that trace

amounts of ceesium can be readily assimilated by direct foliar deposition.34

Russell cites,as well documented, and other author agree, that direct

contamination of plants rather than absorption from the soil is the

dominant uptakre process for major nuclidea, particularly during periods

of high fallout.35,23,34 Evidence for this includes the fact that

vegetation 13Ca levels follow seasonal variations rather than being

accumulative, with amounts in plants being comparable to deposition

during the period of foliage existence.3 This observation is also

consistent with a large discrimination against soil to plant transfer.










Comar refers to foliar absorption of 90Sr.23 Russell states that

it is necessary to consider both direct foliar retention and "plant base

uptake."3 He cites evidence that much of this nuelide found on edible

leaves is actually absorbed at the basal region in the mat of prostrate

stems and surface roots and then transported upwards. In 1964 and 1965,

Wykee observed a reservoir of radioactivity in the vicinity of the plant

base in Upper Midwest grassland when he observed more 137Co and 90Sr per

unit masse in the root-mat traction than in the soil or grees.4

According to Russell, the amount of foliar deposition is comparable

for 1370 and 9Sr, but absorption from the soil is responsible for a

smaller portion of the 1370 reaching edible tissues than for 0Sr.3

He also states that in times of relatively low fallout, the ratio of

137Co to 90Sr in herbage and milk has decreased. This is evidence for a

greater rate dependence relative to the cumulative dependence for cesium

than for strontium.

Comar suggests that ainee milk concentrations of 13Ce (related to

levels in pasture grsas) have not followed the fallout rate in some areas,

it must be assumed that there are also mechanisms for accumulation of

previonely deposited 137Ce.23 This would be consistent with the earlier

mentioned less tightly binding compartment in the organic matter in the

soil. Davie predicts that when the stratospheric load of 1370 becomes

nearly depleted, soil will than become the primary route of uptake.34

Direct floral contamination is reported as a dominant process for

90Sr absorption in cereals but is negligible with storage orgman which

grow beneath the soil since there 18 little downward translocation of

strontium and other divalent catione in plants.35 Comar reviewed reported

that 0Sr accumulates in cabbages mainly by the lodging of rain in











cavities at leaf axile and in potato tubers by the downward leaching

by rain over the stem surfaces. The latter represents a means by which

underground tissues can become contaminated from deposition.2 Neither

author makes reference to mechanisms of 13Ca accumulation in these

crops .

Johnson and ward reported the 13Ca concentration in grain to be

much lower than that in hay.8 Elder and Moore and also Porter et al.

reported that pangolagraea (Dgitri documbene) and Spanish moas

(Tillandata ueneoides) had 13Ca concentrations much higher than any

other plants in the Tampa, Florida, area.98 They concluded that the

nuclide was surface contamination or weakly bound on the grass but was

actively bound on the mose.

A number of author refer to the use of the equation:

C I pd'd Pr r

with regard to radionuclide levels in plants. Element cautions that: it

is an empirical formula and does not necessarily imply understanding of

the mechanisms of transfer into and within a system.3 He makes note of

the fact that pd approaches zero for some plants such as Spanish mosa and

some lichen eand that pr is near zero for plants sheltered from appreci-

able deposition on foliage. A modified form has been presented for 137Ca

in which F2c and p2c are substituted for Fd and pd, respectively, thus

relating concentration to deposition accumulated over the two previous

year rather than to the entire history of accumulated deposition.23

This form presumlably relates to 13Ca released by decay of organic

material and to the less tightly bound deposition in the organic layer

and considers as negligible any uptake of the nuclide tightly bound by

the mineral fraction of the soil. Russell also cautions about~the empirical










nature of the expression and emphasizes that aside from the large errors

normally inseparable from field investigation, deduced relations relate

only to climatic conditions and patterns of deposition which prevailed

during the surveyed or field experiments from which the proportionality

factors were derived.3

Cesium-137 and other radionuclides in animals

Pendleton et al. have briefly summarized literature relating to cesium

and potassium metabolism by aninals.5( Absorption of both cesium and

potassium by mammals is large and takes place through the digestive

tract. These elements enter the body cellsw'heze cesium is more tena-

ciously retained; excretion from the body is urinary and in varying

degrees, depending on species and diet, fecal. Increasing potassiurm

intake has only slight effect in decreasing body cesium content.

According to Davie, the discrimation factor from foodstuffs to

animals (or man) should favor cesium due to preferential assimilation of

trace amounts of cesium relative to potassium.3 Pendleton et al., citing

a number of studies and authors, report that in many animal species the

1370s/potassium ratio in the body is about two to three times higher than

the 137s/potassium ratio in their normal diets (unlike the values

observed for the 90Sr/calcium ratio in animals which are less than one).50

Comar reiterates that 1370 is efficiently absorbed from the gastro-

intestinal tract for transport to musacle tissue and milk.23 .He cites

literature values for concentration in the muscle tissue of cattle of

about 4 per cent of the daily intake per kilogram and values ranging from

10 to 30 per' cent for sheep and pigs.

Hard and Johnson quote literature values for cattle which indicate

that 1 to 2 per cent of the daily ingested dose appears in each kilogram










of muscle tissue,5 Their own work showed 137s levels per kilogram of

edible meat leveling off at less than 1 per cent. of tue daily intake in

mature dairy cattle, at 3 per cent in feed-lot cattle, and at 15 per

cent in calves. These differences may have been due either to age or

feed type, Kreuzer reported a close correlation between 13Cs in meat of

cattle and the methods of feeding and management in Southern Bavaria.52Z

The muscle of grazing cattle vae more heavily contaminated than that of

housed cattle during the grazing season. Change from housing to grazing

was reflected in a rapid increase in levels.

K~ahn et al., in a study of the effect of feeding practices on 137Ca

concentrations in cow's milk, and porter et al., in a study of the Tampa

milkshed, reported that 12 per cent of the daily intake of 13Ca was

tranafarred! to the daily milk production when the animal is in equilibrium

with its diet.58

Eatimatee of the biological half-life of ceeium in the cow, the goat,

the pig, and the hen fall in the range of 20 to 30 days although some

workers report a value as short as 2 to 3 days for the goat.23 In any

event, the turnover in these animal is rapid enough for tissue levels to

show little lag in following dietary levels. Retention of 1370 in the

body is affected by potassium and sodium levels as well as by diuretic

action, but these effects appear to be variable and relatively small.

Russell noted that an error in the eatisate of expected milk levels

of 908r vae systematically related to the particular fallout history of

the preceding year.35 Taking into consideration the use of stored hay as

feed early in the year, he introduced an additional set of terms into the

concentration equation:


C = prF r PdFd 1 P1F










where F1 is the strontium deposition during the second half of the

previous year and pl the "lag rate" factor. With this three-term

expression, he obtained a much better correspondence of predicted values
to observed values.3

Pendleton et al. etate that 1370s is even more available to organisms

living in aquatic environments than in terrestrial environments, and,

because of the trophic level effect already cited, predacious fish may

accumulate this nuclide up to 10,000 times the level in the water.5

Comar reports that 1370 is concentrated in the flesh of aquatic organisms

by a factor of 5 to 20 over that of the surrounding water and Gustafoon

reports high concentrations of 13Ca.in fresh water fish.2545

Casium-137 in man

What has been said about cesina metabolism and distribution and about

the increase in the 1370s/potassium ratio with the trophic level in animal

applies generally to man as well.345 The data of Pendleton t al. indicate

that the increase ratio is larger in adult humans than in children.50

Cesium~-137 retention in humans has been described as multi-

compartmental function, but many workers have found or believe that a

single exponential is a satisfactory expression for most biological

purposes.5,78 Reported half-lives for the longer-lived component in

adults are on the order of -80 to 140O days.

In 1962, Richmond gg 41 measured whole-body retention in four

subjects and reviewed the literature.56 Hardy et al. reported in 1965

on a study of retention of 13Ca and90rolwngcueneso.7

In this study, contaminated foods (1370s and 90Sr, 20 and 60 times higher,

respectively, that in the normal diet) brought back from Rongelap were

consumed by a single individual over a seven-day period. In 1965, McGraw










reviewed the collected measurements of the half-time of this nuclide in

man and suggested a model for expreeaing this parameter as a function of

age.58 Eberhardt reported a different approach in 1967.59 Using

published data from a variety of sources, he derived an expression for

137Cs biological half-life in humane as a function of body weight.

The maximum permissible body burden for 1370 for the occupationally

exposed, as recommended by the International Commission on Radiation

Protection, is 30 microcuries (pWi).60 If one: (1) applies a factor

of one-tenth for members of the general population, (2) assumes that cesiumn

retention can be described with a single exponential function with~half-

life on the order of 100 to 150 days, (3) aeaumes an equilibrium situation

of constant intake, body burden, and excretion, and (4) follows the

Federal Radiation Council reco~mmendation of aeausing that the maximum

exposure by an individual is no greater than three times the average

measured for a population group, then one can derive a maximum permissible

daily intake on the order of 4,000 to 7,000 poi/day. A value of 4,400

pCi/day has been used in the literature.616

Equations have been presented relating dose to 1370 intake and a

number of authors have attempted empirically to fit models relating

measured body burdens to measured levels of 1370 intake and thus predict

future body burdens from intake data.9636

Arctic ecosystems

In 1961, Baarli et al. and Ilden. found unusually high 13Ca body

burdens in people in Norway and Sweden, respectively.676 These initial

findings led to further studies which enggested that unique ecological

situations exist with regard to radionuclides in the fallout-food-man

chain in arctic regions.69-72 Although these regions have lees











fallout than many other areas of the world, levels of 137s in arctic

inhabitants are among the highest documented.

High human body burdened have been traced primarily to the influence

of ecological factor upon fallout accumulation in the lichen-caribou(or

reindeer)-man chain.737 Lichens represent a most important reservoir

of 1370 and other fallout radionuclides because of their longevity

(decades, even one century), persistence of aerial parts, and their

dependence upon nutrients dissolved in precipitation. This effective

retention of 1370 by lichensr, the importance of lichens as a winter food

for caribou, and the dependence upon caribou and reindeer for food by

many northern peoples has resulted in this important 13Ca concentration
poes75,76,77

In the United States, studies of radionuclides in the arctic food

chain were addressed initially to questions associated with the proposed

Project Chariot site located near Ogot~oruk Creekr in northwseern Alaska.l

Since 1963, surveillance activities have continued and expanded in

Alaska.798 The Battelle-Northwest Laboratory has studied the body

burdens of 13Ca in northern Alaskan residents especiallyy in Anaktuvuk

Pass) since the summer of 1962,85

In April and May of 1965, the USPHS expanded the geographic area

investigated by measuring 3Ca body burdens throughout Arlaska.7

Radiation dosage received by the average adult Anaktavuk Pass Eskimo

from 1370 body burdens during 1964, the year of highest values, was

estimated at 135 to 150 moillirem (marem).73 This value is about 30 per

cent less than that amount serving as a Radiation Protection Guide for

population groups during normal peacetime.











`Envirdnaerltal 'IRadioactivlity `Measurements in Florida

Environmental radioactivity sampling and measurement within the

State of Florida began with the collection of sample in 1957 by the

Florida State Board of Health, Bureau of Sanitary Engineering.8 This

soon led to a statewide program of sampling and grose alpha and beta

radioactivity analyses of surface and underground water resources, sedi-

ments, raw and finished water from water supplies, and sewage plant

influents and effluents.2- Some soil, aquatic organisms, and rainfall

vere also included in this early sampling. Gilcreas, Mbrgan, and Vreeland

reported the establishment in 1957 of a routine program involving regular

monitoring of grose alpha and total radioactivity of air and rainfall

at the University of Florida and of surface and underground waters in

Alachua county.8889 The results of these sampling program are

reported in a number of publicatione.2-,69 The University of Florida

program also included twice yearly sampling and grose alpha and total-

activity analyses of plante, animal, and soil.8888

As qa cnsequence of an agreement with the USAEC, the USPHS establish-

ed the Radiation Surveillance Network in 1956 with nationwide stations

for sampling of dry deposition (later discontinued) and air.919 In

1957, the network was expanded and precipitation sampling was added. One

station was designated at Jackeonville under the operation of the Florida

State Board of Health with five to seven continuous precipitation and 24-

hour air sample collected per week. In 1961, a second station was

established at Miani.

In 1960, the Florida State Board of Health estabilished~ similar air

and precipitation easpling stations at Orlando, St. Petereburg,

Tallahassee, and Peneacola; the six stations became known collectively as










the Florida Radiation Surveillance Network.2 Florida data from the

state and national networks are reported in the various iaanes of Re221

o~f Florida Radiological Data.2- In 1963, air sampling station were

aleo established at Tituaville, Cocoa, and Melbourne in the vicinity of

Cape Kennedy.3

In 1953,the USPHS established the National Air Sampling Network--

a survey of airborne particulate pollution, includinB gross beta radio-

activity, in urban and non-urban areas in the United States.9 One

24-hour sample is ordinarily taken every two weeks; sampling frequency

was increased at many station during time of anticipated increased in

airborne radioactivity due to fallout. Stations are designated for

operation either yearly or during alternate years on a staggered schedule.

During the period 1959-1964, stations operated every year both at Tampa

and in the Florida Keye and on more selective schedules in Jacksonville,

Niasi, Orlando, and St. Peteraburg. Reenlts were regularly reported in

Radiological Rlealth ji.E28 Precipitation sarmpling was added at designated

stations with the cooperation of the United Statae Heather Bureau in 1959.

These 'included a station at Tampa beginning July, 1960.

A station of, the 80th Meridian Air Sampling Program was established

at Miami in June, 1957. This network.~of stations near the 80th meridian

(west) was established in 1956 by the United States Naval Research

Laboratory with the assistance of the USAEC, the United States Heather

Bureau, and interested groups in Canada and South America. The stations

sampled ground-level air for measurement of radioactivity neing a variety

of asperiOmenal collecting devices. In 1957, all stations were supplied

with filter samples and blower units, and the network was expanded to

Include locations of interest.to the United Statee Air Force Cambridge










Research Center. It was operated in 1958 and 1959 as part of the

International Geophysical Year Program on Atmospheric Nuclear Radiation

and continued from 1960 through 1962.vith a reduced number of sampling

aites.949 Individual eamples were analyzed for grose beta radio-

activity and samples were composite monthly for analysis for a variety

of specific nuclides. Reports of results and 80th meridian concentration

profiles from 1959 an appeared regularly in Radiolog~ical Health Data.95
Lockhart y). al. summarized the results for 1957-1962 and included a

complete list of reports (26 references) resulting from this program

during that time period.9,9

The USAEC Health and Safety Laboratory (HASL) deposition sampling

program, in operation since 1958, employee two methods of collection for

90Sr analysis.97 In the "pot" method, precipitation and dry fallout are

collected for a period of one month in an exposed etainlese steel pot and

transferred to a bottle for shipping, while in the columnm" method pre-

cipitation and dry fallout are collected in a polyethylene funnel

connected to an ion exchange column which is capped for shipment after a

one-month collection. A station utilizing a pot collector is in operation

at Coral Gables.

Operational responsibility for the 80th Meridian Air Sampling Progrea

was transferred from the Naval Researdb Laboratory to RASL as of

January 1, 1963, to be run in conjunction with the fallout sampling

program.98 Caneurrent with this transfer, gamma malaees, both total-

gamma activity and activity above 1 million electron volta (MaV) energy, were

adbetituted for gross beta analysis as the initial means of sample

evaluation. Ion exchange collectors for deposition sampling were added

to the stations not having them. This resulted in the initiation of a










column collection station at Miami in July, 1963, in addition to the

Coral Gables pot station. Results of the 80th Meridian Program since

1963 and of the depoettion sampling are reported in RASL techateal

reported, and summaries have been published periodically in Radiological

Health Data.2

The USAEC and the United States Department of Agriculture have been

conducting soil sampling,first individually and then jointly,ainee 1955

to determine world-wide distribution of 90Sr.99,100 During this course

of sampling, collections have been made at both Mand. and Jacksonville.

The Appalachicola River at Chattahoochee and the Eacambia River at

Century have both been sampled under the USPHS National Water Quality

Network (cuzzently the Federal Water Pollution Control Administration's

Water Pollation Surveillance System).10 This program was established in

1957 for sampling surface waters of major United Statse river basin for

physical, chemical, biological, and radiological analyses. Weekly grab

samples are collected for analysis at a central laboratory for gross

alpha and gross beta activity in suspended and dissolved solide. Analyses

are performed on either weekly samples or monthly composites, depending

upon the amount of radioactivity expected. Stron~tium-90 analyses have

been performed on selected quarterly composities from each station since

1959. Reenita have been reported for the Appalachicola River For 47

one-month period between April, 1960, and June, 1965, and for the

Escambia River for 39 such periods between May, 1961, and Mhy, 1965.

In 1961, the Water Supply Activity, Interstate Carrier Branch,

Division of Bagineering and Food Protection of the USPHS, established a

Drinking Water Analyasi Program to gather extensive data on the radia-

activity content of water enpplies on interstate carrierel02t Results












have been reported for two samplings each at eva water plants in Fort

Lauderdale, two water plants in Miami, and a plant in Tampa during the

period, 1960-1963.

In addition to the studies of radionuclides in milk already

mentioned, a special study conducted by Consurmere Union in July through

August, 1958, included Miami among 50 North American stations from which

milk samplee were collected for 9Sr and stable calcium analysis.10

In describing shellfish radioactivity research, Lackey reports

the total background activity of oysters collected at two locations in

Florida in March, 1958.10 Gross alpha and grose beta determinations and

gamma apectra vere reported for analyses performed by the USPHlS on oveters,

fish, shrimp, crab, and other biota, as well as on salt water and silt

collected periodically during January, 1962, through January, 1963, from

several locations in Brevard County, Florida.

In summarising results for a variety of food samples, Straub et al.

reported 90r and table calcium levels for one sample each of radishes,

turnips, and trnaip greens from Florida, all collected from Cincinnati,

Ohio, market in 1959.105

In 1959, 1961, and 1962, the Miami area was included in the USPHS-

eponsored Consumers UI~on stuies of S0r, 13Cs, and other radionaclidee

in a typical diet of teenagera.10,0 These studies were carried out

periodically between 1959 and 1964 in a number of cities in the United
States.

Florida easples have been included in the United States Food and Drug

Administration's studies of radioactivity in domestic and imported food

and animal fodder.2,,0










Fifty-six Florida vegetable and citrus samples, collected January

through March, 1964, by the Florida Department of Agriculture, were

analyzed for specific nuclidea by the Florida State Board of Blealth.4

The USPHS Institutional Diet Sampling Network, established in

January, 1961, with 8 locations, was extended to 21 cities, including

Tampa, in October, 1961.10,1 Twenty-one meals plus snacks (three

meals per day for seven days) are collected each month at a participating

school or other institution in the respective cities. Solid food, dairy

products, and wastes are analyzed as separate portions at USPRS regional

laboratories. Reenlts are reported in terms of weight consumed per day

and concentration and daily consumption of calcium, potassium, phosphate,

strontium-89 (89Sr), 90Sr, iodine-131 (1311) 1370s, barium-140 (140Ba)

and either total radium or radium-226 (226Ra). These results appear

periodically in Radiological Health Data.2
In the previously mentioned study of background radiation in Florida,

Willians eg al. reported levels of natural radioactivity in the air from

three Florida cities during 1963-1965, levels of grose alpha and grose

beta radioactivity in food collected in 1964 at various places in the

State, and'groes alpha activity in ash from the 1963 samples of the state-

wide milkr sampling network.29

In addition to the special studies in Florida milkcsheds already

mentioned, Cromroy at al. evaluated the exchange characterietice of soil

from a dairy farm near Tampa and measured 137s uptake from this soil by

diferet rasee.11They reported: (1) a higher 137s level.in

pangolagrase growing at the Teapa farm than in samples from the

Agricultural Experiment Station at Gaineeville, (2) that the clay fraction

of this soil was kaolinite, which exhibited ion exchange and absorption but










has a layer spacing not favorable for "structural absorption," (3) that

the uptake of 137C by this soil in a slurry test was much less than that

reported for other soils, (4) significant uptake from the soil by grasses

transplanted to this soil, (5) different rates of uptake with Bahia-

grass, reaching an equilibrium level more rapidly than pangola, and (6)

that the more slowly equilibrating pangola showed an indication of

progressing toward an equilibrium level about 30 per cent higher than that

of Behia. The thast sampling of a third grass, Bermuda, showed levels

that indicated either a much lower equilibrium level than the other

grasses or a slow rate of uptake. However, retarded growth prevented

further sampling. Unfortunately these authors did not report radioactivity

levels in these graseae prior to treanplanting.

Reported of monitoring sever effluent, air, surface water, and milk

for tritina in the environs of the USAEC's Pinellas Peninsula Plant near

St. Paeereburg have appeared periodically since 1960.30 In 1965, tritium

level were also reported for precipitation collected at Ocala during 1961

and 1962 as part of a global tritium distribution atndy.11

Hartgering described a worldwide sampling program in 1955 and 1956

to estimate human exposure by analysis of 24-hour urine specimens for

isotopes of iodine, strontium, and eesium.11 Participants were five to

ten personnel at each of a number of military installations, which included

McDill Air Force Base, Tampa.

Radioactivity of humans has been measured at a number of installa-

tions. In some of the published reports of 13Ca measurements in humans

at the walter Reed Army Institute of Research, average concentrations have

been tabulated by etates.11,1 The average of six detenninations on

Florida individuals during 1958-1959 was not noticeably different frost










averages in.other parts of the country at that time.11 In addition,

the average 13Ca levels and number of subjects were reported by quarter

for Florida subjects for eix quarters during 1960 and 1961 (a total of

eight Florida subjects).11 Seven Florida subjects were also identified

as haviing been included in the United States averages for July, 1963,

through Auguet, 1964.116

Ceeiump-137 measurements have been made in humana at the Univeretty

of Florida, but results have not yet been published.11 It vae announced

to the press that a whole-body counter survey wee to be made of residents

in the Tampa institution participating in the Institutional Total Diet

Sampling Program, but no published reports were found to date.11

Undoubtedlyraubjects from Florida have been counted at other installations

even though specific Florida results have not been reported in the litera-

ture.

Current environmental radioactivity measurements in Florida

Current sampling in Florida for radioactivity analyses is shown in

Figure 3.

At the present time, grose alpha and total radioactivity measure-

ments continue to be made regularly at the Univeretty -of. Floride on

semples of air, precipitation, sewage, water supplies, and surface water.119

~Moitoring also continues routinely on a statewide basei.114 The Tampa

Pasteurized Milk Network Station collects weekly milk easples; the two

Radiation Surveillance Network Stations at Jacksonville and Miami continue

regular operations. The Florida Radiation Surveillance Network Stations

continue to collect air and precipitation samples, and the State labora-

tory analyzes these samples for grose beta activity. The statewide grab

sampling of enrface and underground waters and of water supplies continues














AlachuB County Surveillance:
(University of Florida)
Air and precipitation (one station),
surface water, water supplies, sewage


Radiation Serveillance Networks
SAir and precipitation

Florida Radiation Surveillance
Network:
O Air only
Air and precipitation

AI Cape Kennedy Vicinity: Air

SPaeteurized Milk Network

X RASI. Fallout Program:
Deposition, pot collector
Deposition, column collector
Air (80th Meridian Station)

Regions indicated are for Florida
raw milk sampling

Not shown
Statewide water sampling
Shellfish sampling


Turkey Point Vicinity:
Air, water, soil,
vregetation


FIGURE 3, CURRENT SAMPLING PROGRAMS IN ~LORIDA HOR
ENVIRONMENTAL RADIOACTIVITY ANALYSIS










for grose alpha and beta analysis. Grab samples of shellfish are

submitted to gamma-spectrum analysis, and then they are ashed and analyzed

for grose alpha and beta activity. Raw milk samples are currently being

collected on a statewide basis for combining into six regional composites

for garmmeaspectrum and 90Sr radiohepemica analyses.

In addition, several special monitoring projects are underway in

the State.12 A cooperative plan has been drawn up by the United States

Air Force, the USPHS, and the Florida Stata Board of Health to collect

environmental samples in the vicinity of Cape Kennedy for radioactivity

analysis. Air is being sampled for gross alpha and beta analysis at Fort

Pierce, Orlando Air Force Base, McCoy Air Force Base, and New Smyrna

Beach; the three previously mentioned state-operated stations at Titusville,

Cocoazand Melbourne function as part of this program. Soil, edible

vegetation (including citrus), and non-edible vegetation are being sampled

regularly and submitted to gamma spectral analysis, while water is collect-

ed and submitted to gross alpha and gross beta analyses of both the

dissolved and suspended solids. Seaples from the 12 eites within the

first 10-mrile radius of the area are analyzed by federal laboratories;

samples from the 10 stations in each of the two 10-mile annuli beyond

this are analyzed by the Florida State Board of Health Radiological

Laboratory .

A special sampling program is also being carried out by the

Florida State Board of Health near the site of the planned nuclear power

pleat at Turkey Point, a facility due to go into operation in the early

1970's.120 Eighteen sites ear sampled on a rotating basia; aix are

sampled per month so that each eite is sampled quarterly. Analyses are

similar to those for the Cape Kennedy off-site area.











Results from the Miami and Coral Gables stations of RASL's air

and fallout sampling program were included in the latest reports of

these program, and results were reported for the environment of the

Pinellas Peninsular Plant of the USAEC as recently as February, 1967,

implying that both these program are currently in operation.0957

Cesiurm-137 and Other Radionuclides in Selected Environmental
Media Methodology and Findings

As will be discussed in more detail in Chapter III, the earlier

observations on radionuclides in Florida milk and feeds and the preceding

review of cesium ecology and Florida radioactivity measurements led to

the selection of meat and vegetables as the major items of study with

nuclide emphasis on 137Cs.

Although thief study is intended to investigate levels and patterns

of radioactivity in specific media, the ultimate significance of the

findings lies in the influence of the observed levels on human radio-

activity intake. Methods of evaluating dietary intake as reported in the

literature can be grouped into three general categories: (1) evaluation

of individual food items end, if all components of a total diet are

evaluated, subsequent computation of total dietary intake, (2) analysts

of the composite total diet of a real or hypothetical individual, and

(3) analysis of urine and feces.1122230

Casium-137 in individual food items

Meat sampling nonally involves selection of some particular muscle,

portion, or product for analysis. It has been reported that the concen-

tration of 1370 can vary from muscle to muscle.12 Fredrikeaon et OL.

reported considerable variation in the rate of cesium uptake between

different muscles with the meet active muscles taking up cesium most










readily and the inactive muscles ultimately reaching a higher content,12

Ekrman reported that the half-time of 13Cs varies between tissues, being

longer, for example, in skeletal muscle than in most other organs or

tissues.12

On the other hand, in a study of uptake and fate of 137s in rats,

cattle, sheep, evine, and poultry, Hood and Comar report that the most

striking feature of cesium distribution in tissues vae the constancy of

the pattern, both between individual and species and between the various

tissues of the body.12

Data reporting environmentally occurring levels of 1370 in meat

or animals in the United States are limited; some of the first data was

from animals maintained in the vicinity of nuclear testing sites. Ceeium-

137 levels were reported for unspecified muscle from cattle sacrificed

in 1957 and 1958 from herds maintained in the vicinity of the Nevada Test

Site, and another reference vae made to cattle sacrificed before and after

the 1961 "Gnome" underground nuclear test in New Mexico.12,2

The United States Department of Agriculture has reported 1370 and

908r levels of beef rib meat surveyed in 1960 and beef soup stock surveyed

in 1961.13 The following year bologna and frankfurters were enrveyed

for 0Sr only, and the results were not significantly different from

those reported earlier in rib meat.

Plummer recently reported very little difference in concentrations

of naturally accumulated 1370 between various muscles of the Georgia

while-tailed deer; this prompted him to use the tongue as an estimator of

general body levels.13 Wettinen reported 1960 and 1961 13Ca levels in

reindeer, potatoes, and certain other food items of Finnish Lapps.72t Re

reports that there is an error of only a few per cent when analyzing the











shoulder of the reindeer as representative of all consumned tissues. He

estimates losses of activity in meal preparation to be about 10 per cent,

but he does not make a corresponding correction in his calculations.

In a' highly detailed study in the United States, Ward and Johnson

reported 13Ca levels in beef from dairy and feed lot cattle at Fort

Collins, Colorado, in 1963.51 They found no differences, wPithin limits

of counting statistics, in content between 12 retail cuts from the same

animal as measured an four different beef animals. They concluded that,

while greater precision in counting may have shown statistically signifi-

cant differences between areas of the carcass, these would be small

compared to the effect of differences in the 1370 contamination of the

various animals' diets.

Straub reported surveys in which individual vegetable crop samples
90 137
collected from market in 1958 were analyzed for Sr, Cs, and other

gamma-emitting radionuclides.10 Food categories reported include fruit,

fruit juices, meat, leafy vegetables, root vegetables, legumes and corn,

and rice.

Setter et al. reported an elaborately planned survey of individual

food items.13,3 Market sampling was performed simultaneously with a

food consumption survey for six quarters beginning July, 1962. Selection

of samples was based on varieties and amounts of food available at the

time of eampling as indicated by the United States Department of

Agriculture marketing reports and local marketing data. Categories

included meat, -vegetables, fruit, and potatoes. During the six calendar

quarters,~ ground chuck beef was sampled for four quarters and lean pork

for two, lettuce for four and cabbage for two, and apples for four and

oranges' for two; potatoes were sampled for four quarters. RLesulta for










137Cs and 90Sr were reported for each of seven regions and the Whole of

the United States. The lowest 1370 levels were found in lettuce,

cabbages, potatoes, apples, and ~egge. These authors stress that .identifi-

cation of food from production areas is difficult because of factors such

as: (1) centralized marketing, (2) raising of the majority of poultry

feed in one region, and (3) raising of beef in one region for fattening

in another on feed from a third.

Highlights of the United States Food and Drug Administration's

prognre of measuring radioactivity in individual domestic and taported

human and animal food items included: (1) a call in 1954 for food

packed prior to the nuclear era, (2) a subsequent program of grose radio-

activity analysts, (3) grose beta activity measurements on a broad basis

sines 1958, and (4) emphasis on 90Sr, 137Cs, and 1311 since 1960.108,134-138

Under this program, results of one 13Ca analysis and about 100 9Sr

analyses were reported for Florida samples collected in 1962 and 1963.2,,0

Laug reported that in this program samples were mostly raw agricul-

tural products, usually un~washed and unpeeled, and generally in the condi-

tion in which they were found in the warehouse or store.13 For the purpose

of data summarization, samples were assigned to classifications such as

vegetables, brassicae, root vegetables, white potatoes. corn, and fruit

(including tomatoes, cucumbbers, pumpkins, and squash, as well as the

bervice, citrus, and other tree fruits). Ceeiumn-137I level were generally

five times as high 'as 90Sr levels. Vegetables ranked in 137Cs content

from highest to lowest as follows: leafy vegetables, dairy products,

brassicae, root vegetables, fruit, corn, and white potatoes. Lang also

states that, although the first year following the resumption of atmoe-

pheric tests vae not marked by dramatic increases of 90Sr in foods,









sporadic higher concentrations were noted in leafy crops. Fallout con-

centrations were reported to be higher in the eastern and central United

States than in the West, an effect believed to be associated with rain-

fall. In an experiment with a leafy vegetable and one kind of brassicae,

commercal processing washingg and canning or freezing) reduced 1370s

by 20 per cent.

The Florida State Board of Health determined and reported 1370s

and zirconiurm/niobium-95 (95Zr/N~b) contents of 56 leafy, non-leaty, root,

brassicae, and miscellaneous vegetable samples and fruit samples that had

been collected by the Florida Department of Agriculture in 1964.4

Bruce reported the levels of 13Cs and 9Sr found in milk, meat,

root vegetables, and leafy vegetables in the United Kingdom during 1962-

1964 and in milk and meat during 1965.13,4 Cesium-137 levels in meat

from cows, sheep, and reindeer in Norway were reported by Hyinden for the

period 1959-1965 and by Madshus for 1964-1965.14,4 Madshus took the

precaution to collect all samples from the semi-tendinous muscle when

sampling meat.14 He also reported average 137C levels by zone for

potatoes and carrots for the fall of 1964. These two items were chosen

for sampling because of universal production. DeRuyter and Aten estimated

intake by humane in the Netherlands by sampling urine and faces.12 Be-

tween November, 1964, and Mlarch, 1965, they also sampled some individual

food items, including milk, grain products, kale, and brussela sprouts.

Uptake of 1370 by some leafy vegetables should be similar to grasses

and legumes. Porter et al, and Cromroy et al., in the studies reviewed

earlier, reported 13Ca levels in grasses and animal feeder collected near

Tampa, Florida.8,1 Caupka published 1370 levels for grass and alfalfa

in Western Slovakia during 1;962-1965r and Nykes reported levels of this

nuclide in grass in Minnesota in 1965.137










The highest 137s levels in lean tissue samples in the United

States are those reported by the National Center for Radiological Health

in a program of monitoring unspecified muscle from Alaskan caribou and
renerduig 18216.2 137
reidee duing196-196. Pendleton et al. reported Ca levels

that were measured in mule deer meat by gamrma counting the hip to knee

portion of skinned hind lege.5
Cesium-137 in the total diet

A number of total diet studies conducted in the United States are

pertinent to this research because they report nuclida levels in

individual food items or categories, illustrate how food items have been

classified into categories, or report effect of food on total intake for

the area and time represented.

In the Consumere Union total diet study, diet representing the total

diet of teenagers for a week in the particular sampling region were

prepared by home economists from produce purchased in local market, and

the composites were submitted for analysis.14

Reference has already been made to the Tampa station of the National

Institutional Diet Sampling Network.10 Ceaium-137 intake levels at this

station have been among the highest in the network, a condition which is

not inconsistent with high milk levels in that area and the fact tbat

dairy products are one of the major contributors of this nuclide. Reports

are available for the January through June, 1966, portion of this study.

Baratta and Williams have made comparisons between these two studies.14

They traced differences in observed level of intake to differences in

amounts of food consumed in each study.

In addition to the program of sampling raw tood items, the Food and

Drug Administration has a total diet study.146,147,148 Sampling in thia











program includes 82 food items in the 11 categories of the food plan

recommended by the United States Department of Agriculture as nutr-ition-

ally adequate at a moderate cost level for boys 16 to 19 years of age

(the highest intake group of the United States population). Items are

sampled in amounts proportional to consumption as reported in the 1955

Household Food Consumption Survey. Samples are collected at designated

cites (none in Florida) in the United States. The categories include

leafy vegetables, smooth vegetables, root vegetables, potatoes, dried beans,
137
fruits, and meat and eggs. The most recent report includes Ca levels

in the total diet at nine cities for February through November, 1965.

In March of 1960, the USAEC instituted a diet study in a single

city.14 This program was later expanded to three stations and it

became known as the Tri-City Diet Study. In this study of the typical

adult diet, foods eae grouped and analyzed in 19 categories with 9Sr and
137
Ca levels reported in each category for each city. Categories include

meat, poultry, fresh fish, shellfish, eggs, fresh vegetables, canned

vegetables, root vegetables, potatoes, dried beans, fresh fruit, canned

fruit, and fruit juides. At Chicago, analyses of these samples for Ca70

have been performed quarterly since 1961. At the other two stations,

these analyses were performed at the and of each year through 1964 and

then quarterly in 1965. Reports for each city include yearly quantity

intake, nuclide concentration, and yearly nuclide intake for each food

category and daily and percentage of total 1370 intake attributable to

the five overall categories of milk, meats, cereals, fruit, and

vegetables.150

Thompean and Lengeman draw, attention to the fact that estimates

of quantity of food consumed do not match the precision of the laboratory










radianuclide measurements.12 By use of different available consumption

estimates, they show how estimates of intake based on the same laboratory

data can vary as much as 75 per cent.

In spite of this potential difficulty. Rivers reported that 1370s

body burdens calculated from intake data were in relatively close algree-

ment to measured body burdene.bl He suggested that diet analysis vae a

useful means of predicting body burden. He also stressed the need for

better analytical techniques and more frequent food measurements.

Using 13Ce/potassium ratios as a basis, Gustafoon examined the

relation between diet and human body burdens.5 Re concluded that diat

corresponded to in vive data when the former vae transformed by a factor

of 3.0 and advanced in time by four months. In the same report, he

extrapolated the human body burden to the end of 1966.

The factor of 3.0 used by Gustafoon to transform diet 1370,/

potaeeium ratios to correspond with body burden levels is consistent with

the trophic level effect discussed earlier.0 The four-month time

advance used in this transformation is probably related to time required

by the human body to equilibrate with changes in the diet and may also be

related to storage of food before consumption.

The Federal Radiation Council developed predictions of the expected

radionuclide levels in the diet in 1963-1965.394 Since then, measure-

ments of radionuclides in milk, the total diet, and hurmans have been

reviewed for the years 1963-1965 and compared to the Council prediction

estimates for these years.616 In addition, levels for 1966 were

predicted using the approach proposed by the Council. The observed values

were in ~agreement with the predictions; the peak of intake by population

groups appears to have occurred in 1964.










Other garmna-emitting radionneclides
In addition to 137Co and 408, food and vegetable samples are

commonly analyzed in the various surveillance program in the United

States by gapmma spectroscopy for any or all of the nnelides 1311

certurm-14r4 (144Ce), manganese-54 (54Mn), ruthenium/rhodium-106 (106Rou/RIh),

sine-65 (65Zn), ad 95Er/Nlb; by gamma spectroscopy or radiochemical

method for 140Ba or barianm/1anthanurm-140 (140Ba/La); and by chemical or
emanation method for total radium or 226Ra. 78,105,106,109,110

The Institutional Diet Sampling Network samplee are analyzed for

poteasium, 13Cs, total radium or R26a, Ba08, and 31.10 However,
in reports for 1966 the latter two were reported to be below detectable

levels. Zirconium/niobium-95 was reported for reindeer and caribou
muscle in 1964.82 Manganese-54, 65Zn, 106R~u/Rh, and ceriumr/praaeodynium-

144 (144Ge/Pr) were rported in lichens, moases, sedges, and other plants
in Alaska during 1959-1961.78 As was noted earlier, the Florida State

Board of H~ealth reported levels of 95Zr/Nb found in Florida vegetable

samples in 1964.4

The presence of 65Za,_a neutron activation product, was reported
in a variety of foods collected in 1958-1959 and attributed to high

altitude fallout by Murthy et al.1 It was reported by Van Dilla in
1960 in beef liver, beef muscle, hamburger, and milk.15

Manganese-54 was reported in human and bovine liver in 1965 and in
freshwater clama in 1966 by Sax and Gabay, and in the Netherlande diet
in 1964-1965.15,5,2

Antimony-125 (125Sb) was reported by Sveneson and Liden in forest

moss in 1965 and by Johnson et .al. in Colorado forage in the years 1962-
1965.15,5 De~uyter and Aten tentatively identified trace amounts of










both 125Sb and beryllium-7 in leafy vegetables in the Netherlands in

1964-1965.12

Cesium-134 was identified in 1960 by Krieger and Groche as a

neutron activation component of fallout from some weapons tests.157

During the period 1960-1964, it was found in air samples, elk, milk,

wheat, and beef in the State of Washington and in caribou and reindeer

meat, fish, and human inhabitants in the arctic.728,5,5 This

nuclide was thought to have wide distribution and to have been produced

prior to 1961. It was present at the level of about 1 to 2 per cent of

the 1370 levels.

Traces of sodium-22 (22Na) hav been reported in vegetables in the

conterminone part of the United States in 1964; in fallout, herbase, milk,

and total diet samples in Italy in 1962-1964; in elk, bass, milk, wheat,

beef, and human urine collected in the State of Washington during 1960-

1964;' and in moose, caribou, and reindeer meat as well as human urine and

Eakimoe in Alaska in 1963-1964.1810618 Perkins and Niaelen

suggest that a considerable amount of 22Npa va generaed during 1961-

1962.15 DeBortolli et al. ehow evidence that this nuclide is taken up

from the soil rather than being deposition rate dependent.16

The activation product, iron-55, has been reported in arctic and

subarctic food chains and residents, and in the blood of residents of the

State of Washington.768 The low energy X-ray, 5.9 thousand electron

volta (keV), emitted by this nuelide does not interfere with the spectra of

other nuclidea previonely discussed and probably would not be detected by

a conventional counting system used to analyse for these othere.85

Nuclear testing will add fresh fission products to those observed

in environmental samples. Klemoent reported that tranetent increases in











air and precipitation radioactivity were observed following the French

nuclear tests of February and April, 1960, but that debris from these

events added not more than0s.1-0.2per cent to the total worldwide fallout

of long-lived fission products.16 lodine-131 and 14Ba were found in

air, precipitation, forage, and, in some cases, milk following the

Chinese nuclear tests of October, 1964, May, 1965, and May,

1966.16,6,6,5,6 The Florida State Board of Health reported a

very pronounced increase of several days duration in the grose beta

activity levels of air in seven Florida cities following the 1964 test.4

Following the 1965 test, gamma analysis of air samples in the United

State showed 131I, tellurium-132, molybdenum-99, and neptuniurm-239 in

addition to 131I and 140Ba/La.165

Naturally occurring radionuclides of the uranium and thorium series

may also be present in environmental samples. In 1960, Muth et al.

reported the radium content of various food in Germany.16 Either total

radium or 22Ra is also reported for several of the total diet sampling

program in the United States.11,6 In reporting a study of gamrma

activity in a variety of plants in the states of Kerala and Madras in

India, Minstry et al. published vegetable ash gamma spectra that very

clearly showed activity from thorium series nuclides as the principal

component.169 Klament reviewed the literature in 1965 and reported

sources and typical levels of natural radionuclides in foods.17

Analytical method

Analytical methods vary from laboratory to laboratory and are

characterized by a combination of innovation and standard physical,

chemical, and radiochemical procedures.






















53



Two of the laboratory systems handling large numbers of environ-

mental examples, the Health and Safety Laboratory of the USAEC and the

laboratories of the National Center for Radiological Health of the

USPHS have issued analytical reports and manuals in a readily available
171-182
form.

Boni has developed a number of procedures for analyeis of 1370s

and other radionuclides in environmental samples.18,8 Other papers

on the analysis of environmental samples by gamma spectroscopy have been

published by Ward, Johnson, and their associates.18,8 In 1966,

Hercer reviewed analytical methods and corresponding references for

measuring radioactivity in food and other biological materials.187










CHAPTER III

EXPERI'MENTAL, APPROACH


The programs of monitoring radionuclides in Florida milk have

indicated that 1370 levels in Florida milk have characteristic geographic

patterns with unusual levels in much of the State. These patterns and

levels are particularly striking when compared to those of 9Sr.

Reports of additional investigations of this situation indicated that

the levels of 13Ca in Florida milk are directly related to levels of

intake of this nuclide by the animals and that high levels in milk are

due to elevated levels in one or more types of locally grown forage.

The findings reported for milk suggested that an unusual radio-

ecological situation exists in Florida. This suggestion in turn prompted

a study of (1) the extent to which these unusual levels and characteristic

patterns of 13Cs extend to other media and involve other nuclides, (2)

the influence of environmental radioactivity on human radiation exposure

in Florida, and (3) some of the reasons for unusual environmental radio-

nuclide levels in tais state.

Selection of Media for this Study

Various media were examined with respect to the following characteria-

ties: (1) their role in the food chain, (2) their distribution in the

State, (3) the importance of their economic role, (4) their capacity for

concentration of radionuclides, and (5) their likelihood of becoming

contaminated. As a result, lean beef and vegetables grown for human

consumption were selected for sampling.






55


.Since cesiumn follows metabolic pathways in animals similar to those

of potassium and is preferentially concentrated by animal, animals and

animal products are important sources of exposure to 13Ca. Beef and

milk are among the most important animal products produced in Florida.

Mlk is an important source of human exposure to radioactivity; dairies

are distributed throughout this state, and the dairy animal receive a

large portion of their feed from local pastures and locally grown forage.

However, milk was not considered in this investigation because it is

already being routinely sampled on a statewide basis and is currently

being studied in detail at, the farm level.

In contrast, there have been no reported studies of specific radio-

nuclidae in Florida meats. In fact, Ward and Johnson referred to the

paucity of any information on 1370 levels in beef.5 Since high levels

of 137C have been reported in forage in parts of the State, beef animaels

deriving a portion of their: diet from these forages will have correspond-

ingly high intakeas of this nuclide. Since ingested-137Ca to distributed

throughout the tissues, particularly the muscle, and because beef is an

important part of the human diet, this commodity is potentially a signifi-

cant source of 137C intake in this htate.

Other animal products produced in Florida for human consumption include

poultry products and pork. However, in this state chickens and other

poultry are commonly raised ~in batteries off the ground and are fed grained

and supplemental feeds largely brought in from outside the production

areaa Consequently these -animals receive little feed from the immediate

environment. Roga receive a variety of prepared feeder as well as refuse

and scraps, but, since Florida is a "grain-poor" atate, much of the hog

feed is also imported. Because of the feed sources and management











practices, poultry, egg, and pork radioactivity levels would probably show

little relationship to the factor influencing the milk levels that

originally instigated this study and therefore were not studied in this

investigation.

From the fact that certain animal forages grown in Florida appear to

have unusual level and distinctive patterns of 1370, it might be

predicted that other vegetation grown under abmilar conditions of

exposure to depoettion and uptake from the soil would have similar

patterns of this nuclide. Vegetables are an important commercial crop in

thia State (400,000 acres, production valued at over $250,000,000 in the

1965-1966 production year), they are consumed directly by man, and some

Vegetable crop or another is produced statewide.18,8

Although occasional 13Ca analyses of Florida vegetable samples have

been reported in the literature, there have been no eystenatic, statewide

studies.

Selection of Beef Sampling Stations

A program was drawn up to sample animals raised at the Florida

Agricultural Experiment Stations with supplementation where necessary by

samples purchased directly from laughter houses or butcher shops. Beef

sampling stations are described in Table 2 and shown in Figure 4.

The beef sampling program was based on information obtained by

consultation with the director of the University of Florida Meat

Laboratory.19 Within the Florida Agricultural Experiment Station

system, beef animals are fed at seven sites within the State. Five

of these eites are identified in Table 2 as Stationa 1, 2, and 3;

Station 4--Source 1; and Station 7. Beef animals are also fed at the

Animal Nutrition Laboratory in Gaineaville but none were killed during











the course of sampling in this study. In addition, beef research is

getting underway at the West Florida Station at Jay, but no animiala were

available for laughter during the course of thief study.



TABLE 2

BEEF SAMPLING STATIONS




Station
Number Location Source of Animals Collection Point

1 Belle Glade Everglades Station Meat Laboratory

2 Ona R~ange Cattle Station Meat Laboratory

3 Brooksville West Central Florida Mhat Laboratory
Station

4 Gaineaville 1. Beef Research Unit Meat Laboratory
2. Local Farmsx Local Packing Plant

5 Pensacola Local Farms, Becambia Local Butcher Shops
and Santa Rosa Counties and Slaughter Housee

6" Graceville Local Farm Farm where Raised

7 Quincy North Florida Station Local Packing Plant
with Assistance of
Heat Laboratory
Director



*Special sampling.
"Special sampling, one sample only.


All of the beef feeding experiments culminate in alaughter and

Trading to determine the marketability (quantity and quality) of the meat

raised under the various feeding programs.19 Experiment station animals

are usually alaughtered at the Meat Laboratory in Gaineaville. In the























5. PENSACOLA L





















i)Experiment Station Sources

SOther Sources


FIGURE 4. BEEF SAMPLING STATIONS










case of the station near Quincy, animal are slaughtered at a local

packing plant in that city, but even these are graded by the director of

the Meat Laboratory.

The sampling of experiment station animals has the advantages that:

the majority of the eamples are available fram..a single source, the

identity of the carease is maintained through the slaughter house, and

detailed recorded are available if needed. These records identify the

history and description of the animal, the feeding program, and the

weight and grade of the carcaes. In contrast, slaughter house animal

are frequently bought at auction and mixed together in holding pens and

carcaes identity is not maintained, both of which make it difficult to

identify the source and history of any sample collected. This is not of

concern if the sole object of the study is to determine the average

radionuclide exposure to the public from meat marketed at a particular

point, but it does present a problem when it also is desired to relate

maet activity levels to specific locations and feeding practices.

Beef Sampling

Since random sampling from certain feeding experiments could have

resulted in the sampling of bullet far in excess of the small number appear-

ing in retail cute on the market, the restriction vae placed that bullet

were to be eliminated from sampling. A further restriction was placed

that anaples were to be from "control" animal or from .those on the

experimental diete most closely resembling the feeding practice of the

particular area.

In sampling from butcher shape or commercial slaughter houses,

samples were taken from meat on hahd at theu time, and special care had to

be exercised to receive eaamples from animals that had been locally grown.











This was no problem in the several cases where samples were collected

from country butcher who fattened their own beef.

Sex, breed, and age were not caneidered as variables in this

experiment, but these and other factors were recorded where available for

possible future use in investigation of any unusual or particularly

interesting results. It was assumed that the distribution of different

easplings from a station (often different experiments in the case of

experiment station samples) and the method of selection would produce

sample representing the average and range of radioactivity levels in

fattened beef raised under various "typical" Florida conditions.

Sampling in May, 1966, of two careassee from each of two experiment

stations confirmed the feasibility of the mechanism of sample procurement,

indicated the sample size necessary for analysis, and tested the sample

preparation, the analytical, and the computational procedurest.

The main beef sampling took place during the period January through

June, 1967. After part of the samples were collected, the 13Ce/potassium

ratio were examined to help determine the total number of samples to

collect. Inspection of the data suggested a trend with highest values in

the southern and central parts of the State and lowest in the northwestern

part. It was assumed that the "within stations" variance for all 1967

sample would not be greatly different from that computed for all samples

collected up to that time (1966 and 1967) and that the final 1967 station

means would not be greatly different from those observed up to that time.

Estimation were then made of sample sizes necessary to show selected

statistically significant differences.

Although inspection of the available data suggested differences

between stations, it was found that, with the assumed variance, at least









eix samples per station would be necessary to conclude that any of these

differences is statistically significant.

Vegetable Sampling

To minimize possible bias introduced by crop differences, stratified

sampling was employed with samples collected within each of three

categories (strata): (1) leaf and stem, (2) fruit, seed, and pod, and

(3) root and tuber. This categorization is generally consistent with the

one used by the United States Food and Drug Administration to su~mmarise

results of analyses of individual vegetables and with the food groupings

used in the total diet studies described in the literature review. If

sufficient numbers of samples are collected in each category, an examina-

tion of category effect is also possible.

Sampling was further stratified within these categories by specifying

a total of 12 crop classifications to be sampled wherever available.

These classifications, shown in Table 3, were set up by selecting and

combining from the approximately 20 different vegetable crope grown in

significant quantities in Florida.18,8

Selection was based on the amount of production and availability

in the State, following consultation with a vegetable crope specialist

from the Florida Agricultural Extension Service. Acreage figures taken

from published reports are also included in Table 3.18 The only high-

acreage crop not included in the sampling vere sweet corn and waterselone.

The corn presented technical problems in the collection and preparation of

sufficiently large easples of the edible portion, and the watermelons are

seasonal in nature and represent only a mall portion of a person's

yearly intake.

The principal harvest saeaon for most vegetables is between October

and June.188,189 Preliminary sampling was carried out in May and June,











1966, to test the feasibility of the sampling mechanism, to develop and

test sample preparation, analytical, and computational procedures, and

to determine the size of portion and counting time necessary to detect

existing levels of radioactivity. Full scale sampling took place between

January and July, 1967.



TABLE 3

VEGETABLE SAMPLING


I


Category Crop


In the case of vegetable sampling, sampling "stations" were identified

by vegetable production areas as adopted from the designation by the

vegetable crop epecialists.18 All samples from fields within one of

these production areas were identified with that particular station

number. In order to perform statistical analyses of the data and keep


AcreagelB
Harvested
in 1965-16
Season

12,100
12,200
14,500
not reported


63,500
16,800
51,600
16,300
10,000


43,500
not reported
not reported


No. oflB88
Areas
Where Gro~n


Leaf, Stem Lettuce, endive, escarole, romaine 8
Celery 5
Cabbage 11
Greens many
All Leaf, Stem 13 without greene

Fruit, Beans, peae 12
Seed, Pepper 10
Pod Tomato 10
Cucumber 16
Squash 13
All Fruit, Seed, Pod 19

Root, Potato 0
Tuber Turnip, Rutabaga many
Other (such as carrots and radishes) 2
All Root, Tuber 10 without turnips















the number of samples to a reasonable level, the State was divided into

regions and each station was assigned to an appropriate region. Initially

the Stata was arbitrarily divided into four regions of approximately equal

area and designated as Southern, Central, Northeast, and Northwest. The

data itself, however, began to suggest that more homogenous regions would

result if the lower east and west coasts were assigned to separate regions.

This resulted in the regional designation shown in Table 4 and Figure 5

and identified as Southeast, Southwest, Central, Northeast, and Northwest.

Sequence of Study

Following sampling, the work was pursued in five stagee:

1. Determination of kinds and levels of gamma radioactivity in the

selected media,

2. Determination of variations in media, geographic location, and

points in time,

3. Identification of unusual levels of gamrma radioactivity in these

media and development of hypotheses concerning causes and mechanisms

involved ,

4. Investigation of the interrelationships of the kinds and levels

of radioactivity in various media, and the relationships with other

available parameters,

5. Estimation of the effect of these nuclide levels cmn the radio-

activity in food products, and in turn, on human radionnelide intake an~d

radiation exposure.















Stations
Number Region Area Represented (county or part of county) Soil Type

1 Southeast Dade Mrl, Rockland
2 Southeast Broward, E. Palm Beach Sande
3 Southeast W. Palm Beach, N. E. Hendry, E. Glades, Eighlands Mucks, Peate
4 Southeast Martin, St. Lueie, Okeechobee, Indian River, Brevard Sands
5 Southwest Collier, Lee, Hendry, Charlotte, 01ades Sande
6 Southwest Hardee, S. Polk, DeSota, E. Manatee Sands
7 Southwest Sarasota Mucks
8 Southwest Manatee, S. Hillsborough, Sarasota Sands
9 Southwest E. Eillsborough, W. Polk Sands
10 Central N. H. Orange, S. E. Seminole, E. Lake Mucks
11 Central N. Seminole, S. Volusia Sands
12 Central Sumnter, Lake Sands
13 Northeast Marion (less Weirsdale) Mucks
14 Northeast S. Marion, S. E. Alachua Mucks
15 Northeast Flagler, St. Johns, Putnam, Clay Sands
16 Northeast Alachua, Union Sands
17 Northeast Bradford Sands
18 Central Citrus, Hernando, Pasco Sands
19 Northeast Gilchrist, Levy Sands
20 Northeast Taylor, Lafayette, Dizie Sands
21 Northeast Colurmbia, Hamlilton, Surwannee Sands
22 Northeast Jefferson, Madison Sands
23 Northwest Gadsden, Leon Sands
24 Northwest Calhoun, Washington, Robmes, Jackson Sands
25 Northwest Eacambia, Santa Ross Sandy Loans
26 Northeast Dural County Sands

a 188
Adapted from University of Florida Vegetable Crop Specialists.
*Corresponds to station numbers as shown in Figure 6.


TABLE 4

IDENTIFICATION OF VEGETABLE SAMPLING REGIONS AND STATIONS*
























NORTHNWEST
REGION











Stations adapted from major
production areas designated
by University of Florida 18
Vegetable Crops Specialists.


SOUTHEAST
REGION


FIGURE 5. VEGETABLE SAMPLING STATIONS









CRAPTER IV

ANALYITICALZ PROCEDURES AND EQUIPMENT


Beef Sampling

The standard procedure for beef sampling was to sample two animals

from each group of animals. The most notable exception was the sampling.

of six animals at one time at Quincy, where there was only one slaughter

of experimental animals during the course of this study. Three pounds of

lean muscle were requested per sample; a total of 5 pounds was requested

when the sample contained untrimmed bone and fat.

In sampling experiment station animals, samples were selected from

the first two carcaeaes hanging in the cooler which met the restrictions

of the sampling deslign (Chapter III). Samples in this case consisted of

the portion associated with the 13th rib (3-4 inches of short loin) from

either side of the carcass. This portion could be collected without

seriously affecting the marketability of a hanging carcass.

In sampling other animals, it was not always possible to sample this

portion or identify the portion sampled, particularly when samples were

obtained through cooperating individuals.

Special samples from a packing plant at Station 4 (discussed in

Chapter V) were collected in the cutting room from animals selected by

packing plant personnel. When picked' up in the shipping department, the

samples were not identified as to the portion of the animal.

Other samples were cut from unspecified lean portions of carcaseae

of locally fed animal on hand.at the butcher shop or packing plant at

the time of easpling.











Vegetalble Sampling

Samples were collected both directly from farms and from markets.

A large proportion of the samples were obtained through the cooperation

of the Chemistry Division of the Florida Department of Agriculture, which

has an extensive program of sampling and analyzing agricultural products

for pesticide residue. The remainder of the samples was obtained directly

by the investigator, who visited both farms and market, and through the

assistance of volunteers, who collected and shipped in samples.

Vegetable samples were requested to be market eamples that had gone

through a washer or were in a condition suitable for washing in the

laboratory. Portions of at least 3.5 kg of edible portion (8 pounds)

were requested. If a large enough single portion were not available, a

sufficient number of smaller portions from the same area vere composited

to make up a sample of the required size. All aamples were identified by

area where grown and, if possible, by farm or nearest community.

Vegetable samples received from the Florida Department, of Agriculture

laboratories were collected according to standard procedures of that depart-

ment.19,9 Briefly, field sample were composite from five portions,

each collected from different parts of the field. Market or packing ehed

samples were composite from portions taken from a number of crater in

order to represent the lot or originating field. These samples were then

sub-sampled at the Department laboratory for analytical purposes, and the

excess portions after sub-eampling were made available for this study.

Some of the Department procedures call for quartering heads of leafy

samples such as cabbage and lettuce with analysis of opposite quarters.

when the original ample did no't include sufficient heads to provide

unquartered heads for this study, unused quarters were provided. In the











case of a small number of samples, the entire sample was sliced before

sub-sampling and the sliced excess provided for this study. In these

cases, the possible effect of unwashed samples had to be considered in

evaluating the data.

Field samplesl collected directly by the investigator or by volunteers

were collected in essentially the same manner as those received from the

Florida Department of Agriculture. Market samples collected by these

individuals consisted of 8 to 10 pounds of produce selected from that on

display at the market at the time of sampling. Market samples were

collected only if the area where grown could be identified.

Beef Sample Preparation

Beef samples were prepared for analysis by boning, trinning the

exceass.fat, and grinding the lean portion twice through a 3/16 inch (in.)

grinder plate.

Vegetable Sample Preparation

In general, analysis of vegetable samples was performed on the whole

of the portion corresponding to the particular category being examined

(leaf and stem; fruit, seed, and pod; or fleshy roat and tuber); samples

were not peeled, cored, or shelled. Tips were not removed from bean pods,

and seeds were not removed from squash and peppers. The entire portion

analyzed was edible although not always eaten.

Unless already washed when received, vegetable samples veza washed

under running tap water, neing a stiff bristled brush where necessary to

remove clinging dirt. They were then drained dry or blotted with a

turkish towel to remove excess moisture. After washing, samples were

chopped into smaller pieces if necessary and triturated with either a

meat grinder or a blender. About 1 milliliter (al) of 40 per cent











formaldehyde per 100 grame of finished sample was added as a preservative.

The tap water used for washing was checked periodically for radioactivity

to assure that washing did not introduce significant radioactivity.

Mbre specifically, tops were cut off turnips, rutabagas, and other

root vegetables at the top of the fleshy root, and stems were removed

from hard skinned squash. These vegetables were washed and cut where

necessary and then ground in two paease through a meat grinder with a

plate with 1/8 in. holes.

Stems were removed from cucumber, peppers, soft skinned squash, and

tomatoes; they were then washed, dried, chopped, and blenderized.

The outer leaves were removed from the cabbage head, the base of the

head was cut off, and the remaining portion was then chopped and blend-

erized. Some cabbage was received as quartered heads; these quarters were

trimmed along the cut faces before chopping to remove dirt and dehydrated

material.

On the few occasions when untrimmed bunches of celery were received,

they were topped near~the center of the leaf cluster, and the upper

portion was discarded; a.portion of the base of all bunches was cut

away. Individual stalks of celery, collards, and turnip, mustard, and

other greens were separated from the bunches and washed, drained, blotted,

chopped, and blended. It was necessary to scrub with a brush to~remove

clinging dirt at the base of the stalk. Collards presented a particular

problem in that they were very tough and required considerably more

distilled water for blending (up to 1,000 at per 3.5-liter (1.) sample)

than did other vegetables.

Reads or bunches of salad greens such as lettuce, romaine, escarole,

and endive were out in halves or quarters which were then further











saparated into clusters of a few leaves for washing, blotting, chopping,

and blending.

The equipment need in sample preparation is identified in Appendix

A. Several different pieces of power equipment were tested for first

stages of sample reduction, but, since these devices had to be borrowed

and returned for each batch of samples, it was deemed more convenient to

prechop by hand with a butcher knife and cutting board.

In grinding, samples were preent only to a size that would paea into

the grinder, ground material was collected in tared containers, the

required amount of preservative was added and hand mixed, and the amount

of preservative and the net weight of the sample were recorded.

The first step in blending was to weigh the washed, dried, and

prechopped samples in a suitable container. A portion of the weighed,

prechopped ample was then~ introduced into the blender along with the

least amount of distilled water necessary to get blending action (none in

the case of tomatoes and cucumbers; about 200-500 al in the case of other

vegetables). Once blending action started, larger pieces of the sample

were introduced and additional distilled water was added only if necessary.

The net weight of sample added to the blender was computed and recorded

after taking the tare weight on the container. Any added water was

measured and recorded by volume; unit density weeas seaned. The weight of

blended material (sample plue water) was calculated and the required

amount of preservative was added to and blended with the sample.

Preserved samples were transferred to labeled wide mouth plastic jars

and held for analyeia. Dilution factor due to added water and preservative

was calculated and recorded for future use in calculating nuelide concen-

trations.










Ga~aa Rladioactivity CunatinR.

Individual pieces of equipment are described in Appendix A. Geamma-

radioactivity analyses were performed with a multichannel scintillation

spectrometry system. The detector was a stainless steel clad 4-in. by 4-in.

right cylindrical sodium iodide (thallium activated) crystal coupled to a

phototube. The detector was located in a shield 20 in, by 20 in. by 24 -;ba,

high (inside dimrensions) with 2-in, thick lead walls, floor, and cover and

with a 30 mil cadmiurm and 5 mil copper lining. Signals are aniklyzed by a

400-channel pulse height analyzer calibrated to 10.0 keV per channel.

Samples were loaded to the full mark in preweighed polyethylene

Marinelli beakers, and the loaded beakers were weighed and placed over the

detector in the shield. Two counting configurations were used; a 3.5-liter

beaker was used for vegetable samples,and a 1.0-liter beaker was used for

meat samples and vegetables of less than 2 liters in quantity. Samples

between 2 liters and 3.5 liters in quantity were diluted to 3.5 liters.

Normally, samples were counted for 50.0 minutes; some of the samples

at the beginning of the study were counted for 100 minutes.

At least two analyses, usually on the same or consecutive days, were

performed on each lean beef sample. All the vegetable samples were given

an initial count, and about two-thirds of these samples were recounted

after 50 to 100 days. The delayed second count helped confirm the tentative

identification of any short-lived activity and permitted recounting of

the longer-lived activity in the presence of much reduced levels of the

short-lived activity.

Gross (background plus sample) spectra for individual samples and

a background spectrum for the particular counting period were digitally

recorded for computer analysis and future reference. Backgrounds were












also subtracted from the individual counts in the analyzer memory, and the

oscilloscope displays of net spectra were inspected visually for the

presence and relative size of peaked. The net spectra of all original

counts and selected recounts were also recorded with the x-y plotter for

future visual reference.

Interpretation of Gamma Spectra

A garmma spectrum, as developed on a multichannel gamrma spectrometer,

is a frequency distribution of counts registered in particular energy

increments. Gamrma rays are emitted by radioactive atoms at one or more

discrete energies characteristic of the particular nuclide. However,

becanee of the nature of the interaction process and the limitations of

the instrumentation, gamma-ray photons of a single energy do not show a

"line" spectrum at the output of the spectrometer system but rather show

a continuous spectrum with an approximately Gaussian-shaped distribution

(photoelectric peak) corresponding to absorption of the total energy of

the photon plus a lower energy portion (Compton continuum) corresponding

to smaller fractions of the total photon energy. In addition, the spectrum

may show effects related to the configuration of detector and shield, such

as backscatter peaks or escape peaked peakede lower than the principal peak

by the amount of energy carried 'wvay by X-rays escaping from the detector)

and may also show secondary peak~ corresponding to additional photon

energies emitted by the nuclide.) The resolution or width of the photo-

peakg the shape of, and ar under, the Compton portion of the apactrum

relative to the photopeak) and the importance of backscatter and escape

peaked are functions of configuration and composition of the particular

sample, detector, and surroundings.











The number and energy of specific photopeake are utilized in identi-

fying specific nuclides. The quantity of nuclide in a particular sample

is determined from the area under some portion of the spectrumn

(such as the photopeak portion). The counts in a selected region are

summed, and a conversion or "efficiency" factor, appropriate to the

nuclide, ample configuration and counting eyetem, is applied to convert

this sum or area to the amount of nuclide in the sample.

In the case of a mixture of more than one gamma-emitting nuclide in

a sample, the spectrum reflects all of the contributors and is assumed

to be a linear combination of the individual contributorse Because of

the limits of resolution (width of the photopeaka), additional peake at i

other energies, and the Compton portion of the individual spectra, some

unabers of the mixture will contribute counts in the region of, or in

some case even obscure, the principal peake of various other members of

the mixture.

In thief study, gamma spectra were first inspected vianally for the

presence, location (energy), and relative size of peaks and then were

evaluated by a computational procedure.

Computational procedures for interpreting gamnma spectra vere reviewed

in the manual recently issued by the National Center for Radiological

Realth.19 The method need in this study is the one described as the

"Simiultaneous Equatione Method." This method vae chosen for a nahrber of

reasons. It was the method most familiar to the investigator at the time

of the beginning of the study and it vae being used an a large number of

public health laboratories at that time. This method in less subjective

than the leesselaborate stepwise nulide-by-nuclide trippingn" method,

and errors in the' estimation are not compounded successively in one










direction as severely as when stripping is performed. In addition, it is

less sensitive to instrument instability than some of the more sophisti-

cated method and once the initial simultaneous calibration equations

have been solved, computations can be performed with a calculator or

even by hand if necessary.

Briefly, in this method the interference between some number (N) of

contributors to a composite spectrumn are corrected for by setting up and

solving a system of N simultaneous equations involving the unknown

contributions of the N nnelides in terms of counts in the photopeak

regions. The original equations are developed from counting a standard

of each of the nuclides separately with the eyetes and in the configure-

tion to be used for the unknown samples. Once the simultaneous equations

have been solved to yield explicit equation for each nuclide, these

same latter equations can then be used for all subsequent sample computa-

tions until such time as the system needs recalibration.

A computer program for calibration computations was written in

FORTRAN II and later converted to FORTRAN IV for use with the Univeretty

of Florida IBM 709 computer. This program reads the conditions of the

calibration and the counting data for the various standard. It then

averages any replicate counts for the same nuclide, computes the matrix

corresponding to the coefficients of the simultaneous equations, inverts

the matrix in order to obtain the coefficients for the explicit equations,

and computer counting efficiency (counts per disintegration) in the

photopeak region for each of the nuclidea. Identifying information,

the computer coefficienta, and computer efficiency are printed out and

all the necessary calibration information is also punched on card

for subsequent nee in computations. For performing the subsequent

























75



sample calculations, a program was written in FORTRAN II, later converted

to FORTRAN IV for the IBM 709, and also converted to FO)RTRAN IV for use

with the University of Florida IBM System 360 computer. This latter

program reader in the calibration coefficients and efficiencies and reads

the background counts and sample groes counts for each ample. It then

computes and writes out the concentration and the associated evo-standard

deviation counting error of each specified radionuclide in terms of

disintegrations per minute and pCi per unit (vteight or volume).









CHAPTER V

RESULTS OF BEEF SAMPLING


Individual samples were collected from 45 animal at seven different

stations.* Duplicate analyses vere performed on the lean portion of each

of these samples with repeat duplicate analyses on one sample for a total

of 92 lean beef analyses. Four of the samples were collected from two

stations during the preliminary work in May, 1966, and the balance were

collected between January and June, 1967. A departure from the original

plan took place when temples were collected at Station 4 from several

groups of animals that were obviously not fed to the same degree of

finish as the majority of the animals. The data from Station 4 are given

special Coneideration in this presentation of result.

The major gamma-emitting nuclides observed in the beef samples were

137Ce, 40K, and 226Ra and its decey products, bismuthh-214 (214Bi) and

lead-214 (214Pb). Quatitative comlputations were made for 137Cs, 40K,

and 226Ra in equilibrium with its daughters. It was necessary to include

the latter activity in order to correct for the interference with the

determination of 1370s and potassium by the 214Bi that occurred in a

large number of the beef samples. No particular significance is placed

on the quantitative values for radium and daughters since there was no

assurance that equilibrium actually existed and, indeed, no attempt was




*The single sample collected at Station 6 consisted of lean stew
meat from the farm's retail outlet and although it vae counted here as
one animal, it may actually have represented more.










made to prevent the lose of the gaseous radon-222 intermediate. Ceei~um-

137 is reported as p~ilkg of vet weight and as picocuries per gram a

potassium (pCi/g K). Since eeaentially none of the potassiurm is

contained in the fat, the latter method of reporting compensates for

variations in the completeness of trimming of the fat. On the other hand,

it obscures the effect on 13Ca of fat distributed through the lean.

Cesium-137 Content of Lean Meat from Grain-Fed Beefs 1967

A summary of 137Cs concentration, potassiurm content, and 137Ce/

potassium ratios of lean meat from grain-fed Florida beef sampled in 1967

is shown in Table 5 and in Bigure 6. There is an apparnt: gradual decrase

in 1370 content from south to northwest. The highest station average was

296 pCi/kg (78.8 pCi/8 K) at Ona and the lowest station average was 105

pCi/kg (31.8 pCi/g K) at Peneacola. The highest individual value, 539

pCilkg (133.6 pCi/g K), vae also found at Ona and the lowest individual

value, 55 pCi/kg (16.3 pCi/g K) occurred at Pennacola. The statewide

average of all samples was 214 pCilkg (54.4~ pCi/g K).



... Average of 8 samples
~ __...-1 from 1966 and 1967





S40



No. of Samples: 16 161 6 21 16 111 1

Station No. 1 2 3 4 7 6 5

FIGURE 6. CESIUM-137 CONTENT OF LEAN MEAT FROM
GRAIN-FED FLORIDA BEEF--1967
















1370 K 1370s/potassiurm

Location dAimals Ave. Range~i~ Av.Ragv~Te. Ri~ange~


TABLE 5

SUMDbRY OF CESIDM-137 COtTENT OF LEAN MEAT FROM GRAIN-FED FLORIDA BEEF, 1967


1 Belle Glade

2 Ona

3 Brooksville

4 Gainesvirlle

7 Quincy

6 Jackson County
(Graceville)

5 Pensacola


Statewide Average
of Samples

Average of 7
Stations


263 j; 10

296 + 13

211 j 11

173 + 19

214 + 10


109 403

163 539

153 283

142 -203

182 277


3.65 j; .10

3.66 + .12

3.57 ]; .11

3.53 1 .19

3.44 + .11


3.26 4.22

3.30 4.04

3.09 3.97

3.31 3.75

3.27 3.58




2.97 3.82


71.0 j: 3.4

78.8 + 4.4

58.4 + 3.7

48.4 + 5.9

62.1 + 3.6


51.1 1 8.7

31.8 + 3.3


30.4 95.3

49.5 133.6

49.5 72.5

42.5 54.3

53.0 77.4




16.3 54.0


1* 175 + 26

6 105 + 10


--- 3.43 + .26

55 174 3.37 + .11


33 214 + 25 55 539


3.53 + .05 3.09 4.22


54.6 + 1.6 16.3 133.6


--- 3.52 + .06


57.4 + 1.9


-265 + 6


*Confidence intervals represent the two-standard deviation counting; error only
variance from all sources.

**This single sample was a composite of lean beef from meat in the show case at
have represented more than one animal.


and are not based on the total


the farm cormmissary and may











The effect of geographic location on 1370 content of lean meat

from grain-fed Florida beef was tested by performing an analysis of

variance on the 1370/potassium ratio reported for the samples at the

five stations from which the full complement of six samples were collected

(Stations 1, 2, 3, 5, and 7). This analyeia, presented in Table 6, shows

that, at the a = 0.01 level, there is sufficient evidence to indicate

a location effect.



TABLE 6

CBSIUM~-137 CONTENT OF LEAN MEAT FROM GRAIN-FED FLORIDA
BEEF, 1967--EEFECT OF GEOGRAPHIC LOCATION
(EXPRESSED AS CESIUM-137/POTASSIUM RATIO)

ANALYSIS OF VARIANCE




Degrees Sum
of of Mean
Source Freedom Sqiuaree Square F

Station 4 7,526.77 1,881.69 4.56

Error 25 10,312.11 412.48 --


Total 29 17,838.88 -- --


***
Significant at the ar = 0.01 level.



The data were then examined to determine where significant differences

occurred. The same five stations were arranged in order of 137Ce/potassium

ratios and the Tukey procedure for simultaneously testing all paired of

meeanswas applied.194 A~s shown in Table 7, the "eastern" tatitona (1, 2,

7, and 3) constitute a group for which there is insufficient evidence to













indicate a significant difference between stations, but all stations in

the Broup are significantly different from Station 5. The "northern"

stations (5, 3, and 7) constitute a similar group, differing significantly

from Stations 1 and 2. The inability to establish the significance of

any smaller differences in station means is due to the high variation

within stations. It is possible that by increasing the number of samples

per station and/or by reducing the within station variance (such as

blocking on some variance contributing characteristic not identified

here) more of the apparent station differences could be demonstrated to

be statistically significant.



TABLE 7

RANKING OF FIVE FLORIDA BEEF SAMPLING STATIONS ACCORDING TO
CESIUM 137/POTASSIUM RATIO OF LEAN MEAT

BASED ON 1967 SAMPLES, SIX GRAIN-FED ANIMALS PER STATION





Station 2 1 7 3 5

Average pCi/g K 78.8 71.0 62.1 58.4 31.8







Solid lines indicate stations showing no significant difference at the
ar = .0 level.

Simultaneoualy testing of all possible paired of means according to the
procedure of Tukey.194














Inspection of the data suggests a trend of highest 1370 levels in

the southern part of the State, intermediate in the central and north-

eastern part of the State, and lowest in the far western part of the

State. Statistical testing of the data supported the hypothesis of a

location effect and supports the hypothesis of a systematic geographical

trend to the extent that the data can be grouped into two overlapping

groups of adjacent stations.

Effect ~of fPear 6f Collection

'twJo samples each were collected at Station 1 and 2 during May, 1966,

and six samples each were collected at the same stations during 1967.

As shown in Table 8, the two stations appear to show temporal trends in

opposite directions, so that any overall year-to-year difference is

insignificant, at least for the amount of data available.



TABLE 8

EFFECT OF YEAR OF COLLECTION ON CESIUM-137 CONTENT
OF LEAN MEAT FROM GRAIN-FED FLORIDA BEEF




No. of Samples 1370s pCifk 37et nf
Station 1966 1967 1966 1967 Ave. 1966 1967 Ave.

1 2 6 189.0 263.0 226.0 55.0 71.0 63.0

2 2 6 374.0 296.0 335.0 100.1 78.8 89.5

Ave. 281.5 279.5 280.5 77.5 74.9 76.2











EffeCt of Feeding Progreer and Meet gOality on casine-137 Level.

After cancellation of a scheduled kill of experiment station animals

at Station 4, an attempt was made to obtain alternative samples from

animals grown in the same general area. It was not possible in the time

available to obtain samples that were of the same quality of meat as those

obtained from experiment station' animal a 399 that were positively

identified as locally fed. It was possible to obtain four samples from

a local packing pleat consisting of unidentified cute from four locally

fed animals. This meat was intended for ground beef and meat products

(frankfurters, bologna, etc.) and was of a mudh lower quality than meat

which is usually sold as retail cute. These animals, slaughtered in

April, 1967, were identified only as "two had some grain, two fed

primarly grass."*

As shown in Table 9, two U)SDA GOOD samples collected in January,

1967, from two steers fed corn and eitrue pulp on an experiment station

dry lot in this same general area had 137C levels of 204 and 142 pCi/kg

(54.3 and 42.6 pCi/g K), respectively. Reference to Table 5 shows that

these values fell within the general range of all the "eastern" samples.

By contrast, the four packing plant samples had 137C contents ranging

from 293 to 12,500 pci/kg (90.4 to 3,710 poi/g K). 'Two of these animal

had 137s levels that were of a general magnitude about equal to rangingg

frDS oDB to two thmee) those of the other "eastern" samples and the other

two had levels 10 to 100 times as high. It was suspected at this point




*Cormenwt by the packing plant manager on the feed of these and
subsequent animal from this source werce probably based on inspection of
the condition of the animal and quality of the meat.























83



that the higher levels of 1370 in the meat were due to animal diets

composed primarily of grase. Several weeks later, four additional samples

were obtained from the same packing plant along with as much identifying

information as obtainable in order to further investigate this source of

meat. As shown in Table 9, all of these animals were cows of varying

breeder, the meat were of low grade, and again two samples were~ identified

as from grass fed animal and two from animals that had received some

grain. A range of results very similar to the first four samples was

obtained, with the totally grase-fed animals having the highest 13708

levels.

















Sample Animal 137C 1370/
No. Description Feed Heat Grade pCifkg pfke pCify

Samples from University of Florida Beef Research Unit (trimmed from short loin)
Collected 1{7/67
7 Steer Dry lot: corn, Good 204 j; 29 3.75 ]; .30 54.3 j 8.9
8 Steer citrus puilp Good 142 + 24 3.31 + .24 42.6 + 7.8

Sampoles from local packing plant buying only local animala (trimmed from unidentified portions)*
Collected 4(26/67
36 293 + 24 3.24 + .24 90.4 + 9.9
39 4 animal identified only as "two had 507 + 29 3.51 + .27 144.0 + 13.7
37 some grain, two fed primarily on grass" 1,840 + 36' 3.69 +C .27 498.0 + ;37.8
38 12,500 + 73 3.36 + .28 3,710.0 + 309.0
Collected 5/10(67
50 Rereford cow Some grain Utility 567 + 27 3.90 + .26 145.0 + 12.0
53 Bereford cow Some grain Cutter 808 +e 41 4.09 +e .38 198.0 + 21.2
52 Jersey cross cow Grass-fed Not specified 5,530 + 68 4.97 + .40 1,130.0 jo 97.2
51 Brahama cow Grass-fed Canner 9,840 + 64 3.62 + .27 2,720.0 j; 200.0



"Confidence intervals represent the two-standard deviation counting error only and do not include other
sources of variance.

Commpents concerning feed of these animals were supplied by packing plant. They are probably based on
conditiDR Of animals and appearBaCe Of meat.


TABLE 9

VARIATION OF CESIUM-137 CONTENT OF LEAN FLORIDA BEEF AS
INIFLUERCED BY FEEDING PROGRAM AND GRADE OF MBAT









CHAPTER VI

RESULTS OF VEGETABLE SAMPLING


A total of 165 vegetable samples were collected, analyzed, and

evaluated for gammna-emitting radionuclide content. Of these, 29 were

collected during the preliminary sampling in May and Jurne, 1966, from eix

different stations in four regions. The remaining 136 were collected

during January through July, 1967, from 19 stations in the five -designated

regions. As surmmarized in Table 10, the 1966 aamples represented 10

different crope and the 1967 eamples represent the 12 designated crop

classifications.*

The principal radionuclides detected in vegetable samples in addition-

to 40K were 137Cs and naturally occurring 226Ra and ite daughters.

Following the arrival of fresh fallout, presumned to be from Chinese

nuclear weapons teete, short-lived nuclides (half-lives on the order of

one weekc) appeared briefly and moderately long-lived activities (half-

lives ranging from one month to one year) appeared and gradually

diminished.

Ceatum-137l results are considered first in this chapter, and a

consideration of other nuclide results follows.







"Crope, categories, stations, and regions are defined in Chapter III.






















Year. Category .;-SE SW C NE NW-a State Total
1966

Leaf, Stem 3 0 11 0 0 14
Fruit, Seed, Pod 1 7 3 0 2 13
Root. Tuber 0 0 2 0j
All Categories 4 7 16 g 2 29

1967

Leaf, Stem 14 13 13 9 9 58
Fruit, Seed, Pod 14 12 116 7 50
Root. Tuber 1 6 0 12 j[ju
All Categories 29 31 14 37 25 136

1966 6 1967

Leaf, Stem 17 13 24 9 9 72
Fruit, Seed, Pod 15 19 4 16 9 63
Root. Tuber -1 6 12 9 3
All Categories 33 38 30 37 27 165


Cesium-137 Content6 of:Florida Vegetables--
Average Levels and Reaion 'Variation

The resulted are sumrmarized by region for each of the two

period and for the total study in Table 11 and in Figure 7.

feature of these results is the wide range of values reported

all regions.


TABLE 10

NUMBERS OF FLORIDA VEGETABLE SAMPLES ANALYZED FOR GAMRA
RADIOACTIVITY BY REGION, CATEGORY, AND SAMPLING PERIOD


sampling

A striking

for nearly



















S- May-June, 1966 January-July, 1967 1966 & 1967
Region N R R 'N R Nl 2 R

SE 4 50 + 10 0-111 29 24 + 6 0-176 33 27 + 5 0-176
SW 7 71 j 9 24-110 31 104 + 7 0-357 38 98 + 6 0-357
C 16 64 + 7 0-561 14 118 +11 26-356 30 89 + 6 0-561
13E 0 NS NS 37 48 + 6 0-214 37 48 +6 0-214
N1W 2 24 + 20 23- 25 25 23+ d 0- 67 27 23 + 6 0- 67

Regions 4 56 + 7 24- 71 5 63 + 3 23-118 5 60 + 4 23-98
Samples 29 61 1 5 0-561 136 58 + 3 0-357 165 59 + 3 0-561


Year 1966 1967 1966-1967


TABLE 11

CESIUM-137 CONTENT OF FLORIDA VEGETABLES
SUMMARY BY SAMPLING PERIOD AND REGION


N = auaber of samples or regilons
P I average, pCilkg wet weight
R I range of sample or region average, same
NS = not sampled


units as mean


Confidence intervals of means are based on the two-standard deviation
counting error only and do not include other sources of variation.


NS-Not sampled
**** Average of all
samples


FIGURE 7. CESIUM-137 IN FLORIDA VEGETABLES ACCORDING
TO SAMPLING PERIOD AND REGION WHERE GROWN










The 1370s content of the 29.eamples from 1966 averaged 61 pCi/kg

(vet weight) while the 136 siamples from 1967 averaged 58 pCi/kg with an

overall sample average for all 165 samples of 59 pCifkg. The data

suggest a geographic trend with maximum values in the regions designated

Southwest and Central, the lowest values in the Southeast, and Northwest,

and intermediate values in the Northeast.

The apparent regional effect was tasted for the 1967 sampling period

with an analysis of variance. Examination of the data showed that the

variance increased in a general fashion as the mean increased and that

frequency distributions of sample means were skewed to the right. Both

observations suggest that in spite of other sources of variation, the

analytical results were strongly influenced by the behavior of radio-

active decay, which can be described by a Poisson distribution (variance

equal to the mean). Accordingly, in order to stabilize the variance,

the data was transformed for the purpose of the analysis of variance by

taking the square root of the reported sample means. From this analysis,

shown in Table 12, it can be seen that there was sufficient evidence at

the ar = 0.01 level to indicate a regional effect.

The Scheffe procedure was need to test the transformed data to

determine which of the regional averages were significantly different.194

As is shown by the ranking in Table 13, the central, southwest, and

northeast regions constitute a group for which there is insufficient

evidence to indicate a significant difference between regions, but all of

these regions are significantly different from both the northaest and

southeast regions. The northeast, northwest, and southeast regions also

constitute a similar group, differing significantly from the central and

southwest regions.




Full Text

PAGE 1

CESIUM-137 AND OTHER GAMMA RADIOACTIVITY IN THE FLORIDA ENVIRONMENT A STUDY OF SELECTED MEDIA By CHARLES ERVIN ROESSLER A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHV UNIVERSITY OF FLORIDA December, 19ff7

PAGE 2

n 68-13,030 ROESSLER, Charles Ervin, 1934CESIUM-137 AND OTHER GAMMA RADIOACTIVrTY IN THE FLORIDA ENVIRONMENT A STUDY OF SELECTED MEDIA. The University of Florida, Ph.D., 1967 ^ Health Sciences, ptiblic health University Microfilms. Inc., Ann Arbor, Michigan

PAGE 3

1 AOCNOWLEDGMENTS The author acknowledges with gratitude Dr. Billy G. Dunavant, the chairman of his supervisory committee, for direction, encouragement, and invaluable assistance. He also acknowledges assistance of his committee co-chairman. Dr. Herbert A. Bevis, especially for making many of the financial arrangements which were necessary for sSnple procurement. He wishes to acknowledge the other members of his committee. Dr. Harvey L. Cromroy and Dr. John A. Wethington, Jr. He especially wishes to thank Dr. E. G. Williams and others of the Florida State Board of Health for their assistance and willingness to provide pertinent data and information. Recognition also is given to the radiological staff of various county health departments, to various county agents, and to staff members of the Chemistry Division of the Florida Department of Agriculture for their assistance in selecting and locating sampling sites and in collecting samples. He wishes to thank Dr. John E. Moore for making computer time available and for providing some of the technical facilities necessary for the dissertation study and Dr. A. Z. Palmer for his assistance in planning and conducting of beef sampling. Appreciation is also extended to Dr. James Montelaro for vegetable sampling advice, Mr. Lawrence Fitzgerald for programming assistance, and Dr. John I. Thomby for statistical advice. The author also expresses his thanks to Mary Redrlck for typing of the final manuscript. 11

PAGE 4

Finally, the author is deeply indebted to his wife, Genevieve, who provided valuable assistance in nearly all phases of this project and h.i wishes to acknowledge his children, Terry, Cindy, Mary, Francis, Kay, and Jean, for their patience and occasional assistance during the course of his graduate study. The work was supported in part by United States Public Health Service Training Grants No. 5-TlBH3-07(67) and No. 3-TlRH30-04Sl(66) . ill

PAGE 5

TABLE OF CONTENTS Page ACKNOWLEDGMENTS • ^^ LIST OF TABLES "^^ LIST OF FIGURES viii ABSTRACT ^* CHAPTER I. INTRODUCTION • 1 II. REVIEW OF THE LITERATURE 4 Reviews of Environmental Radioactivity ......... 8 Sources of Environmental Radioactivity 10 Ecology of Ceslum-137 and Other Environmental Radioactivity 11 Environmental Radioactivity Measurements In Florida . . 32 Ceslum~137 and Other Radionuclides In Selected Environmental Media — Methodology and Findings .... 42 III. EXPERIMENTAL APPROACH ....... 54 Selection of Media for this Study 54 Selection of Beef Sampling Stations . 56 Beef Sampling 59 Vegetable Sampling 61 Sequence of Study ..... 63 IV. ANALYTICAL PROCEDURES AND EQUIPMENT 66 Beef Sampling 66 Vegetable Sampling . 67 Beef Sample Preparation 68 Vegetable Sample Preparation « . 68 Gamma Radioactivity Counting 71 Interpretation of Gamma Spectra 72 Iv

PAGE 6

Page V. RESULTS OF BEEF SAMPLING ^^ Cesiuin-137 Content of Lean Meat from Grain-Fed Beef, 1967 ![ Effect of Year of Collection °^ Effect of feeding Program and Meat Quality on Cesium137 Levels ^^ VI. RESULTS OF VEGETABLE SAMPLING 85 Ceslum-137 Content of Florida Vegetables—Average Levels and Regional Variation 86 Effect of Year of Sampling on Ce8ium-137 Levels in Florida Vegetables ^" Cesivim-137 Content of Florida Vegetables— Other Observations , ^ Other Gamma-Emitting Radionuclides 100 VII. DISCUSSION OF RESULTS ^°3 Geographic Variation of Cesi\jm-137 103 Other Variations in Ce8ium-137 Levels 105 Magnitude of the Observed Ce8ium-137 Levels Ho Influence of Observed Ce8ium-137 Levels on Human Intake and Exposure . 122 Possible Mechanisms and Factors Influencing Cesium-137 Levels in Florida 130 Other Radionuclides 133 Discussion of Sources of Error 13'» Further Investigations Suggested by the Results of This Work ^^^ VIII. SUMMARY AND CONCLUSIONS 1^3 Conclusions ^^^ APPENDICES ^*® A. EQUIPMENT AND INSTRUMENTATION 150 B. GAMMA-EMITTING RADIONUCLIDES IN THE CALIBRATION MATRIX . 153 154 LIST OF REFERENCES BIOGRAPHICAL SKETCH ^^^

PAGE 7

LIST OF TABLES Table Page 1. STRONTIUM-90 DEPOSITION IN THE UNITED STATES (MILLICURIES/ MILE2) 17 2. BEEF SAMPLING STATIONS 57 3. VEGETABLE SAMPLING 62 4. IDENTIFICATION OF VEGETABLE SAMPLING REGIONS AND STATIONS . . 64 5. SUMMARY OF CESIUM-137 CONTENT OF LEAN MEAT FROM GRAIN-FED FLORIDA BEEF, 1967 78 6. CESIUM-137 CONTENT OF LEAN MEAT FROM FLORIDA BEEF, 1967— EFFECT OF GEOGRAPHIC LOCATION (EXPRESSED AS CESIUM-137/ POTASSIUM RATIO) . • • • • 79 7. RANKING OF FIVE FLORIDA BEEF SAMPLING STATIONS ACCORDING TO CESIUM-137/POTASSIUM RATIO OF LEAN MEAT . 80 8. EFFECT OF YEAR OF COLLECTION ON CESIUM-137 CONTENT OF LEAN MEAT FROM GRAIN-FED FLORIDA BEEF 81 9. VARIATION OF CESIUM-137 CONTENT OF LEAN FLORIDA BEEF AS INFLUENCED BY FEEDING PROGRAM AND GRADE OF MEAT 84 10. NUMBERS OF FLORIDA VEGETABLE SAMPLES ANALYZED FOR GAMMA RADIOACTIVITY BY REGION, CATEGORY, AND SAMPLING PERIOD . . 86 11. CESIUM-137 CONTENT OF FLORIDA VEGETABLES— SUMMARY BY SAMPLING PERIOD AND REGION • • 87 12. CESIUM-137 CONTENT OF FLORIDA VEGETABLES, 1967 SAMPLESEFFECT OF GEOGRAPHIC LOCATION 89 13. RANKING OF FIVE FLORIDA VEGETABLE GROWING REGIONS ACCORDING TO CESIUM-137 CONTENT, 1967 SAMPLES 89 14. COMPARISON OF CESiUM-137 LEVELS IN FLORIDA VEGETABLES— 1966 AND 1967 SAMPLING PERIODS 91 15. AVERAGE CESIUM-137 CONTENT OF FLORIDA VEGETABLES— SUMMARY BY CATEGORY, REGION, AND YEAR OF SAMPLING 93 vi

PAGE 8

Table Page 16. RANGES OF CESIUM-137 CONTENT IN FLORIDA VEGETABLES SUMMARIZED BY REGION, CATEGORY, AND SURVEY PERIOD 94 17. CESlUM-137 LEVELS IN FLORIDA VEGETABLES, HIGH INDIVIDUAL SAMPLES 1°° 18. CESIUM-137 LEVELS REPORTED IN BEEF AND OTHER MEAT BY VARIOUS INVESTIGATORS 1°^ 19. CESIUM-137 LEVELS REPORTED IN VEGETABLES BY VARIOUS INVESTIGATORS ^ 20. FLORIDA VEGETABLE SAMPLES WITH HIGHEST CESIUM-137 LEVELS, DRY WEIGHT BASIS ^21 21. CESIUM-137 INTAKE ESTIMATED FROM PUBLISHED VALUES 123 22. CESIUM-137 INTAKE ESTIMATE FOR THREE FLORIDA CASES, 1966-1967 125 23. REPORTED BODY BURDENS OF CESIUM-137 128 24. EQUIPMENT AND INSTRUMENTATION 150 25. GAMMA-EMITTING RADIONUCLIDES INCLUDED IN THE CALIBRATION MATRIX • 1^^ vli

PAGE 9

Figure LIST OF FIGURES Page 1. CESIUM-137 AND STRONTIUM-90 IN PASTEURIZED MLLK— COMPARISON OF THE FLORIDA STATION TO NATIONAL AVERAGES AND RANGES • ^ 2. RADIONUCLIDES IN FLORIDA MILK— YEARLY AVERAGES BY REGION . . 7 3. CURRENT SAMPLING PROGRAMS IN FLORIDA FOR ENVIRONMENTAL RADIOACTIVITY ANALYSIS 6. CESIUM-137 CONTENT OF LEAN MEAT FROM GRAIN-FED FLORIDA BEEF— 1967 • 7. CESIUM-137 IN FLORIDA VEGETABLES ACCORDING TO SAMPLING PERIOD AND REGION 11. GEOGRAPHIC VARIATION OF CESIUM-137 IN FLORIDA MILK, BEEF, AND VEGETABLES 40 58 4. BEEF SAMPLING STATIONS . 5. VEGETABLE SAMPLING REGIONS AND STATIONS 65 77 87 8. CESIUM-137 IN FLORIDA VEGETABLES, CLASSIFIED BY SAMPLING STATIONS WITHIN CATEGORIES, 1966 AND 1967 96 9. CESIUM-137 IN FLORIDA VEGETABLES, CLASSIFIED BY REGIONS WITHIN CROPS, 1966 AND 1967 98 10. CESIUM-137 IN FLORIDA ^TEGETABLES, CLASSIFIED BY CROPS WITHIN REGIONS, 1966 AND 1967 ^^ 104 vlil

PAGE 10

Abstract of Dissertation Presented to the Graduate Council in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy CESIUM-137 AND OTHER GAMMA RADIOACTIVITY IN THE FLORIDA ENVIRONMENT ~ A STUDY OF SELECTED MEDIA By Charles Ervin Roessler December, 1967 Chairman: Billy G. Dunavant, Ph.D. Co-chairman: H. A. Bevis, Ph.D. Major Departmeilt: Bioenvironmental Engineering A study was performed of the kinds, levels, and distribution of gamma-emitting radionuclides in the Florida environment. The investigation was Initiated because of the unusual levels and characteristic 137 geographical patterns of cesium-137 ( Cs) found in Florida milk and forage in earlier studies. Beef and yegetabl'is were selected as the most important media for sampling. Sampling was carried out in May and June, 1966, and during January through July, 1967. Analyses were performed by gamma spectroscopy on triturated whole samples. Complex gamma spectra were interpreted in terms of the individual contributing components by use of the simultaneous equations method. 137 The most significant gamma-emitting radionuclide present was Cs, and the evaluation of the data was concentrated on this nuclide. Levels of "''^''cs in both beef and vegetables showed geographical patterns of variation similar to those reported earlier by others in Florida milk. Maximum levels were found in the central and southern parts of the State, with intermediate levels in the northeastern and Ix

PAGE 11

north central parts of the State, and the lowest levels in the northwestern part of the State. In addition, vegetable samples showed a marked difference from southeast to southwest, with average levels in the southeastern part of the State as low as in the northwestern part. The levels of Cs in lower-quality meat from animals that had fed primarily on grass were much higher than those in high-quality meat from feed-lot animals. These levels were higher than any other levels reported in beef in the conterminous United States. 137 There was no apparent difference in Cs concentrations between leafy, fruit, and root categories of vegetables; although certain crops in each category did exhibit consifttently higher levels than the other crops in the same category. Cesium-137 concentrations found in this study were compared to literature values, both to those reported for years previous to this study and to 1966-1967 values obtained by extrapolating published values to that time. Ce8ium-137 concentrations in both beef and vegetables in much of the State were considerably higher than the estimated national averages for the same period; average concentrations in the regions exhibiting the lowest average levels were found to be comparable to the estimated national averages. 137 The significance of the observed Cs levels was evaluated in terms of the human intake of this nuclide. It was estimated that radioactivity intakes from locally produced food in Northwestern Florida would be similar to the national average. Three hypothetical cases of assumed diet composition and source of food were set up to evaluate levels in the remainder of the State. Consideration of diets with various combinations

PAGE 12

of Florida milk, beef, and vegetables having the average levels shown in much of the State resulted in predicted Cs intakes and body burdens ranging from two to 20 times the projected national average. The intakes, body burdens, and resulting whole-body radiation doses estimated for the various cases considered were all less than the applicable radiation protection guides, but the guides could be approached by individuals constantly consuming food at the extreme levels found. It was concluded that unusual environmental factors or mechanisms are involved in the levels of Cs found in the Florida environment. The possibility of such mechanisms has important implications to waste disposal, hazard evaluation, and nuclear facility operation. The mechanisms were not identified but there is increasing evidence that the role of uptake from the soil is greater than that reported for most areas of the country. xl

PAGE 13

CHAPTER I INTRODUCTION This research Involved a study of the kinds, levels, and distribution of gamma-emitting radionuclides in selected segments of the Florida environment with emphasis placed on the nuclide cesium-137 (I^^qs) in animal and vegetable products. This study was initiated because of unusual levels and characteristic geographical patterns of 137c8 found in Florida milk and forage in earlier studies described in Chapter II. Milk monitoring programs of the United States Public Health Service (USPHS) and of the Florida State Board of Health have indicated that the average levels of ^^^Cb in milk in much of Florida have been higher than the national average and among the highest in the nation for a number of years, while strontium-90 (^°Sr) levels have been consistently average or below. Further investigations have shown a consistent geographical pattern within the State, > and it appears that these levels are primarily related to the intake of 137c8 by cows through the medivim of locally grown forage. The major effort in this study was directed toward determining the extent to which these unusual patterns of '•^^Cs are reflected in other elements of the human food chain, particularly lean beef and truck vegetables. In addition, measurements were made of other gamma-emitting radionuclides in all samples.

PAGE 14

Slpilflcance of this Research First, it is important to the welfare of the people of Florida that the extent to which persons in the State are exposed to radiation from all sources and by all routes be known. This study contributes to this knowledge by (1) investigating the 137 extent to which the elevated levels of Cs previously observed in milk and forage extend to other media, particularly other elements of man's food chain, (2) determining whether other gamma-emitting radionuclides show elevated levels in Florida, and (3) evaluating the potential influence of these nuclides and their levels on man's radiation exposure. In Chapter II, it is pointed out that many routes of radiation exposure have been and are being evaluated In Florida. Gross alpha and beta radioactivity levels are measured in a variety of media in this state. Detailed studies have been performed in selected localities, and exposure to specific nuclides through the route of milk is being studied in great detail. However, this work represents the first extensive, statewide study of exposure to specific nuclides through food chain elements other than milk. Second, the information developed here to estimate exposure levels should also contribute to the understanding of the mechanisms involved in 137 the previously mentioned unusual levels of Ca in Florida. It also is important to predict and evaluate the impact on the environment— and, eventually, on human health— of nuclear activities such as the operations of nuclear power plants, nuclear laboratories, and nuclear powered vehicles. A thorough, systematic study of radioactivity in the State provides a baseline of radioactivity levels against which any future increases can be compared. This means determining not only

PAGE 15

average levels of various radionuclides for the purposes of comparison but also normal variations of these levels for use both in designing future surveys and in determining whether apparent increases are significant. In addition, knowledge of the mechanisms and rates of transfer of radionuclides through the environment provides a basis for predicting the consequences of accidental releases of radioactivity. At the same time, since intentional waste release is governed by criteria based on various assumptions concerning the normal behavior of radionuclides in the environment, it is important to be aware of any unusual behavior such as suggested by the Florida milk l^^cs levels. Finally, this study is significant in that the data collected will contribute to other environmental radioactivity study efforts in the State. For example, these data can be used to complement the study of 137ca in Florida milk~being carried out by the Florida State Board of Health and to serve as an extension to the environmental monitoring being carried out in the Cape Kennedy off-site socio-economic impact area by the United States Air Force, the USPHS, and the Florida State Board of Health.

PAGE 16

CHAPTER II REVIEW OF THE LITERATURE This study was undertaken as a direct result of the findings of earlier studies of radioactivity in Florida milk and dairy feeds carried out by this author and others. The USPHS began a program of sampling raw milk for radioactivity analysis in 1957, and out of these initial efforts grew the present USPHS Pasteurized Milk Network which has 63 stations, at least one In every state of the Union, the Canal Zone, and Puerto Rico. A station representing Florida became operative at Tampa during August, 1960. In this network, a composite sample is taken from the pasteurized milk marketed in the community and shipped to a USPHS laboratory for radionuclide analysis. Average monthly l^Tca and ^^Sr levels at the Florida station of the network are compared against the corresponding national ranges and averages for the period 1961 through February, 1967, in Figure 1. Consistently, the average levels of ^^''cs at the Florida station of this network have been well above the national average; since mid-1964, they have been the highest in the sampling network. In contrast, ^Osr levels have not been particularly high; with the exception of two months, they were consistently below the national average. As a result, the ^^''ca/^^Sr ratios have been particularly high. Workers at the Florida State Board of Health initiated a program in 1961 for the statewide collection and regional compositing of raw 2-7 milk from a 10 per cent random sample of the dairy farms in the state.

PAGE 17

300 -M H H iJ CO W200 100 Network Maximum ^^^^ Network Average $^^£^i^Network Minimum • Florida Station CESII3M-137 ff'j^WYfl^fmm 1 1 1 1 I I I I M l I i ' " " ' ' " " I ' "J ' il" " I' ' ' ^'JlcL^'^ i961 I 1965 ' 1963 • 1964 * 1965 • 1966 ' FIGURE i. CESIUM-137 AND STRONTIUlt-90 IN PASTEURIZED MILK—COMPARISON OF THE FLORIDA STATION TO NATIONAL AVERAGES AND RANGES

PAGE 18

Figure 2 summarizes ^^^Ca and ^^Sr results for 1963 through 1966. It shows that the average results reported for pasteurized milk samples from the Tampa station of the national network are comparable to the average results for composite raw samples collected from the same general region. The figure also shows that the Tampa station results for both nuclides are reasonably well representative of the reported average of all milk produced in Florida, particularly the area east and south of Tallahassee. There does appear to be a gradual transition from lower ^37cg levels in the northwestern part of the State to higher levels in the eastern, central, and southern parts of the State with the highest in the central part of the State. Figure 2 also shows that -'-^''Cs levels in the northwestern part of the State are below the .State average. These levels fall more rapidly with time than levels in the remainder of the State and fall from above the national network average in 1963 through 1965 to below it in 1966. Statewide average ^^Sr results are consistently below the national network average and remain fairly constant for the eastern, central, and southern parts of the State. These results show a greater fluctuation in the Northwest — even rising above the national network average in 1965 and 1966. Porter et al. , in a special study of the Tampa milkshed during October, 1963, through February, 1964, observed considerable farm-to-farm variation within that area and concluded that the elevated milk levels were due to elevated levels of ^^^Cs intake by the animals and not to o unusual transfer of the nuclide from the feed to the milk. They also identified pangolagrass (Digitarla decilmbens) as the principal contributor to the high ^^^Cs intake.

PAGE 19

a:

PAGE 20

In 1964, Roesaler and Williama initiated a study to investigate more 9 fully the factors influencing radionuclide levels in Florida milk. Unpublished reports of their work also show a high farm-to-farm variability in milk radionuclide levels. These results suggest that when examining more farms on a wider geographic basis, equally high or higher intakes 7 can be attributed to forages other than pangolagrass . Reviews of Environmental Radioactivity The interest in environmental radioactivity since the early 1950 's Is evidenced by the large number of bibliographies, hearings, symposia, conferences, and books devoted to the subject. Hoard, Eisenbud, and Harley prepared an extensive bibliography on radioactive fallout in 1956, Because of growing public concern at this time about the possible effects of fallout from nuclear weapons testing, the Joint Committee on Atomic Energy of the Congress of the United States held hearings on radioactive fallout and its effects on man in 1957, and 11 12 again in 1959. * The scientific community explored the question of radioisotopes in the biosphere in a symposium in 1959 and again in the 13,14 First National Symposium on Radioecology in 1961. The United States Atomic Energy Commission (USAEC) sponsored a conference on radioactive fallout from nuclear weapons tests in 1961 and again in 1964. Eisenbud authored a text on environmental radioactivity in 1963, and a collection of papers reviewing the ecology of radioactive fallout, soils, 17,18 plants, foods, and man, edited by Fowler, was published in 1965. Natural environmental radioactivity was the subject of a symposium 19 20 in 1964 and a 2,000 reference bibliography by Klement in 1965. ' The proceedings of a symposium on radiation and terrestrial ecosystems in 1965, edited by Hungate, review radioactive fallout phenomena

PAGE 21

and mechanisms, primordial and cosmic-ray produced radionuclides, soilplant relationship, and radionuclide cycling as well as present results 21 of individual research. The Second National Symposium on Radioecology was held in 1967, at which time emphasis was placed on reporting individual investigations of both effects of radiation on the environment 22 and behavior of radionuclides in the environment. Comar reviewed the literature up to January, 1965, relating to the movement of fallout radionuclides through the biosphere and man; Ellis reviewed and appraised the levels and biological significance of current 23 24 fallout levels in the United Kingdom in 1965. * The fallout pattern in the Nordic countries was a topic at a proceedings of the First Nordic 25 Radiation Protection Conference in Sweden in 1966. About the same time Leistner, on behalf of Euratom, reviewed the reported research on the radioactive contamination of foods of animal origin, tabulating reported 26 distributions, retention, and ambient levels. A book edited by Russell in 1966 is devoted entirely to radioactivity 27 and himian diet. In August, 1959, the President of the United States directed the Secretary of Health, Education, and Welfare to collate, analyze, and Interpret data on environmental radiation levels. This assignment resulted in the appearance in April, 1960, of the publication, RadloloRlcal Health Data (subsequently changed to Radiological Health Data and Reports) . This monthly publication contains regular reports of routine national and worldwide monitoring programs operated by agencies of the United States as well as frequent special reports of state monitoring programs, special studies, special evaluation of particular problems, and u 28 topical reviews of current research.

PAGE 22

10 Sdutfcea of Ettvlroiiinental Radioactivity According to the best present knowledge, man has always been exposed to varying degrees of natural background radiation from cosmic radiation and from naturally occurring radionuclides. Elsenbud points out that the world Inventory of radioactive materials prior to World War II, both In the environment and In the laboratory, was confined to those which occurred In nature, with the exception of a relatively few mllllcurles of radioactivity produced In cyclotrons during the late 1930 's. Construction of large nuclear reactors during the war and the associated operations for extracting plutonlim from Irradiated uranium resulted In the first extensive occasions for contaminating the environment with radioactive substances. Then, In the late 1940 's and continuing at an accelerated rate throughout the 1950* s, there began a series of nuclear weapons tests that resulted In a worldwide distribution of radioactive materials In all segments of the environment — the atmosphere, the soil, food chains, and man himself. Elsenbud lists the principal sources of environmental radioactivity as natural radioactivity, preparation of nuclear fuel through the stages of mining, concentrating, milling and fabrication, reactor operations and accidents, conventional radioisotope use, aerospace applications of radioisotopes and reactors, fuel reprocessing and radioactive waste 17 disposal. Comar identifies the major source to date as radioactive 23 debris from the testing of nuclear weapons. On the other hand. Important future sources will likely be nuclear reactor operation, radioisotope use, and radioactive waste disposal. Williams et al . pointed out that varying levels of natural radioactivity do occur in Florida and that these materials do have an

PAGE 23

11 Qpportunity to become relocated in the environment through the operations of phosphate mining, phosphate fertilizer production, and subsequent use 29 of the by-products. With regard to the other sources of environmental radioactivity just mentioned, there is no uranium mining, concentrating, or milling, nor fuel fabricating or reprocessing, nor large scale or commercial radioactive waste disposal in the State. Reactors are presently limited to the University of Florida Training Reactor, and there have been no reported contaminating incidents in the State. The Pinellas Peninsular Plant of the USAEC is located near St. Petersburg, Florida, but from the regular published reports of the contractor's environmental monitoring in the vicinity, it may be inferred that radionuclides potentially reaching the environment from this plant 30 are limited to tritium. This means that, with this exception, at the present time any widespread radioactivity in the Florida environment must be naturally occurring radioactivity or must come from fallout injected into the atmosphere. At the same time, the environmental mechanisms affecting activity from these sources will affect in much the same manner any future radioactivity from local contamination sources. With regard to the future, several nuclear power plants are definitely planned for the State of Florida and it is likely that radioisotope or reactor powered electrical generators or propulsion devices will be used in future vehicles launched from the missile testing and 31 space flight complex at Cape Kennedy. Ecology of Cesium-137 and Other Environmental R adioactivity It was pointed out in the preceding section that, with certain local exceptions, the major source to date of environmental radioactivity is radioactive fallout from the nuclear weapons testing. Cesium-137 and

PAGE 24

12 ^^Sr are considered biologically to be the moat important radionuclides in long-range fallout because of their long physical half -lives, the high yield of these nuclides in fission, and their respective chemical 23 32 similarities to the natural body constituents, potassixmi and calcium. Indeed, the majority of studies of special nuclides in the environment appear to be concerned with these two nuclides. 137 The remaining examination of the literature emphasizes Cs, but gives attention to other nuclides to the extent that they might also 137 appear in samples examined for Cs. In 1959, Langham and Anderson reviewed blospheric contamination from Cs. They estimated production by weapons tests and deposition up to that time, reported important exposure routes to man, and listed an 33 137 extensive bibliography. They proposed expression of Cs levels as '^^Cs per gram of potassixmi because of the metabolic similarity of cesium and potassium. A later exhaustive review of cesium ecology was made by 34 Davis in 1963. In 1965, Comar summarized and updated this information in a concise, yet comprehensive, review, of the movement of fallout nuclides through the biosphere. He observes that cesium and potassium are chemically similar. However, since they are not metabolically interdependent, the 90 •'•^^Cs /potassium ratio is not as meaningful as the Sr/calcium ratio. Nevertheless, Cs concentrations are often expressed relative to 40 potassium for two reasons: (1) naturally radioactive potassium-40 ( K) and ^^^Cs are often measured simultaneously by gamma spectrometry, with ^^K thereby serving as an internal standard, and (2) in man, the cesium/ potassium ratio correlates better with lean body mass and hence with radiation dose than does the •'"^^Cs per kilogram (kg) of body weight.

PAGE 25

13 The worldwide deposition of ^^''cs is usually estimated by applying a •'^^Cs/^^Sr ratio to the values of deposition of ^°Sr since it has been studied more extensively. The ^37cs/90sr ratios vary between 1.0 and 3.0 as these nuclides are produced, but this ratio will change markedly as the two elements pass through metabolic systems. Radionuclide pathways to man Fallout radionuclides reach man primarily through plants, either by his consumption of foods of plant origin or indirectly by his consumption 33 of animal products. Plants become contaminated by radioactive materials from the atmosphere by either (1) indirect contamination which occurs when radioactive materials enter the soil and passes into the plant through the roots as do soil nutrients or (2) direct contamination in which the material is deposited on some portion of the plant and passage through the soil is bypassed. ^^ Direct contamination reflects events of the recent past, varies with the rate of deposition, and is designated "rate dependent." Indirect contamination is governed by the total amount available in the soil and is designated "cumulative dependent." Indirect contamination has the characteristics that (1) material deposited before the plant develops can still enter the plant, (2) short-lived radionuclides that enter the soil will have a high probability of decaying to insignificant levels before reaching the plant roots, and (3) radioactive substances entering the soil may be diluted with soil substances, rendered unavailable to plants by fixation to soil materials, or discriminated against in plant uptake. The concepts of cumulative and rate dependent contributions to radionuclide levels in an environmental component are illustrated in the generalized expression:

PAGE 26

14 where C = concentration of the radionuclide in the sample on interest, Fj = cumulative deposition, a F «=» current rate of deposition, and p , and p are the proportionality factors for cumulative deposition and deposition rate, respectively, for the particular system and nuclide _ . 23,35,36 tinder consideration. Once radionuclides are deposited on or incorporated into plants, the grazing animal effectively collects contamination from plant material and concentrates it in animal products; however various factors such as metabolic behavior of the specific nuclide and animal feeding and management practices influence the relationship between the amount deposited 23 in tissues or transferred to secretions that are used for food. In order to select Important media for further study and to consider possible movements of radionuclides in the Florida environment and possible geographic, media, and temporal variations, it is necessary to review briefly what is known about the passage of radionuclides, particularly '^^Cs, through various segments of the environment. Origin, transport, and deposition of radioactive fallout Klement and Langham both reviewed fallout phenomena and mechanisms in 1965.^^*^^ Klement Identified the sources of injection of radioactivity into the atmosphere as nuclear weapons tests, peaceful nuclear explosives testa or utilization, reactor operations, and space applications of nuclear energy. He placed weapons tests foremost from the standpoint of widespread environmental radioactivity. The radioactivity can include fission products (over 200 different nuclides of about 36 elements between

PAGE 27

15 atomic numbers 28 and 65) and activation products that come about as a result of neutron Interaction with soil, air, water, or parts of the nuclear device at the time of the detonation. Radioactive debris Is usually apportioned Into three fractions: (1) fallout In the Immediate vicinity, (2) material injected into the troposphere, and (3) material Injected into the stratosphere. Local fallout is not a concern In this Florida study, but tropospherIc fallout can deposit short-lived nuclides in the weeks immediately following atmospheric weapons tests. Deposition from tropospherlc contaml*' nation is governed by tropospherlc air flow and should be highest at the latitude of injection with. a certain amount of dispersion and displacement and with local low altitude variations due to terrain such as 17,36 mountains and land-water contrasts. One exception is the downward and equatorward movement along Isoentroplc surfaces of debris Injected into the upper polar troposphere. A second exception is the poleward movement and sinking in subtropical regions of midand uppertropospherlc injections in equatorial regions. Material Injected Into the stratosphere may remain there from several months ;. to several years and provides the source of long-lived materials currently being deposited on a worldwide basis. Stratospheric materials are transferred to the troposphere, from which deposition is primarily 36 due to precipitation with a small Increment due to dry deposition. 90 List et al. described the generalized worldwide deposition of Sr up 37 to late 1963. The mean latitudinal distribution lu the Northern Hemisphere showed a very low deposition in the vicinity of the north polar region, a rapid Increase to a maximum between 40° and 50° N, and then a gradual decrease in the vicinity of the equator. Davis prepared a similar

PAGE 28

16 137 latitudinal deposition curve for average Ca content of precipitation for 1955-1958. Florida lies between 25° and 31° N, a location whose deposition on the mean distribution curve lies midway between the I
PAGE 29

17 effect on the precipitation effect, assigns most of the State of Florida to another immediate area with "an expected lesser fallout compared with the 'wet' eastern United States because of its subtropical location." Estimates of ^°Sr deposition in the United States through 1966, derived from several sources, are shown in Table 1. Values for years beyond 1966 can be obtained by an extrapolation based on the assumptions that deposition is described by a single exponential function and that there will be no significant additions to the stratospheric content. _ . TABLE 1 strontium-90 deposition in the united states (millicuries/mile2)

PAGE 30

18 2 where D = deposition, picocurles per square meter, (pCi/m ) , 3 Ca ° air concentration, pCl/m , H ° height of fall constant, m, a " dlmenslonless factor to account for dry deposition Into the precipitation collector, b = elimination constant, (inches of rain) , and r = rainfall amount, inches. Further study is necessary before the various relationships can be clearly 36 defined. Air concentrations and deposition rates show a peak during the spring of each year which is related to entrance of debris from the stratosphere during late winter, spring, or early summer. After new tropospheric injections, peaks in concentrations are seen along the path of the cloud, and air measurements are particularly useful to determine arrival time of new debris at specific locations and thus anticipate the rise in levels in other media. Atmospheric contamination of fallout Cs is not considered an inhalation hazard. Radionuclides in water In his 1965 review, Klement also summarized some of the observations 36 of fallout radionuclides in water reported up to that time. He stated that short-term variations in deposition are probably not as detectable in fresh surface waters as they are in surface air, but that the same seasonal variations are seen. Relative concentrations of nuclides in surface waters vary with local deposition rates and characteristics of the local aquatic environment. Large differences can be expected within a major river or lake because of runoff and flow.

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19 Langham and Anderson concluded that drinking water contamination 137 33 with fallout Cs does not constitute a health hazard. However, water 137 may have an Importance In the food chain In that Cs Is more available to organisms living in aquatic environments than in terrestrial environments . Cesium-137 and other radionuclides in the soil 43 Schulz reviewed soil chemistry in 1965. He listed fission products likely to be found in the soil, classified elements according to their mobility in the soil, and discussed the use of soil chemistry in predicting plant uptake of radionuclides. Ctmiulative levels of radionuclides in the soil and their distribution in depth, important factors in plant uptake from the soil, are affected 36 by weathering and other disturbing influences. In most soils in the 90 United States, Sr does not appear to leach very rapidly (supporting the validity of soil sampling as a means of determinliag accumulated fallout deposition) . Virtually all of the nuclide is found in the upper 8 inches of these soils. In medium to fine textured soils, about 75 to 90 80 per cent of the deposited Sr is found in the upper 2 Inches and even in medium textured soils similar proportions are found in the upper 4 inches. A number of authors have cited the fact that cesium is readily 34 36 43 44 retained by soils. * * ' Its sorption is characterized by high adsorption onto mineral particles (the ion exchange properties of soil being largely associated with clay minerals in the soil complex), but there is a certain amount of disagreement over the mechanism of this :e (the 34,36 137 fixation. Nearly all of the Cs is found near the surface (the top 2.5 centimeters) of undisturbed soils in the United States.

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20 Downward movement of cesium In undisturbed soils is even less than 137 strontium. After five years, 50 to 80 per cent of added Cs remained 23 in the upper 5 centimeters with little penetration below 10 centimeters. It is pertinent to the Florida soil scene that, in batch experiments, sandy loams and clays absorbed 90 per cent of the available cesium, 34 while sand absorbed only 50 per cent. Ranges of pH commonly encountered have little effect on cesium sorption since it is approximately constant above a value of 3.5 (though 34 decreasing rapidly below pH 3.5). While cesium is desorbed by cations of neutral salts, more readily by K than by Na or Ca , it effectively competes with potassium in interactions in the soil. Trace amounts of cesium adsorbed by the soil are held more strongly than strontium. Russell states that the extent of ^••'^Cs fixation in soil depends upon the clay content and is inversely related to the organic matter in which cesium remains less strongly bound. ^^ Schulz states the chelation of nuclides by soil organic matter 43 may cause them to keep some mobility in the soil. Complementary ions have a strong influence on the redistribution of 43 nuclides in the soil profile. For example, it is expected that the amount of soluble calcium will have a direct effect on the mobility of Sr^ and Ra^^ in soils and consequently on the ease of uptake by plants. 43 Alkali cations present a more complicated case. With regard to '^^Cs, complementary ions can be classed into two groups: (1) those having little effect on cesium, such as dilute H"^, the alkali cation Na , and the alkaline earth Ca'*^-, Mg-^-, and Ba-H", which solubilize or release less than 10 per cent of added carrier-fre^^^^Cs and (2) those liberating moderate amounts of bound cesium, such as Cs"*", NH4+, K+, and Rb+, which

PAGE 33

21 free 20 to 80 per cent of the cesium to a labile form. Typical agricultural soil in the neutral pH range possesses primarily Ca and Mg as 137 labile Ions. These have little effect in releasing added Cs for plant uptake. Movement of cesium-137 and other radionuclides from tha soil to plants A number of experiments in nutrient solution Indicate that cations 34 apparently compete against cesium in uptake by plant roots. In one experiment at low external cesitim concentrations, potassium, rubidium, 137 ammonia, and cesium were markedly effective in depressing Cs uptake by barley roots, while sodium, lithium, calcium, and magnesium were not; at 137 high concentrations, all inhibited , Cs absorption. Millet, oats, buckwheat, sweet clover, and sunflower discriminated slightly against rubidium and strongly against cesitan in favor of potassium. In another experiment, 137 an increase in the potassium of the solution decreased Cs uptake by bean plants but resulted in an increased potassium content of the plants . At low potassium levels, barley showed high selectivity for potassium relative to cesium; however at high concentrations, uptake was less selective in favor of potassium. On the other hand, other investigators reported that adding potassium had only a small effect — a 100-fold increase in potassium reduced "'•^''cs uptake by only a factor of two and non137 45 radioactive cesium enhanced Cs uptake. Uptake by plants from soil is influenced by both the availability of the element in the soil and the inherent behavior of the plant with regard to available elements. According to Menzel, plant concentrations of various radioactive elements , after they have been added to the soil in water-soluble forms, may be several orders of magnitude higher or lower than the concentration in the soil.*^ He classifies elements into

PAGE 34

22 five classes of uptake, ra^nglng from strongly concentrated to strongly excluded by assuming that the behavior of radioactive elements In the soil-plant system Is Identical with that of stable nuclides of the same element. In general, those nuclides that are most readily absorbed are soluble In the soil or are Isotoplc with elements that have metabolic functions In the plant. Conversely, those that are least absorbed are quite Insoluble In the soil. Notable examples are strontlxm, slightly concentrated; radium, not concentrated; and cesium, slightly excluded 137 Removal of Cs from the soil Is Inhibited by the strong fixation In uptake from the soil. om the soil Is Inhlbd 23 34 35 In the soil but uptake varies with soil type. 137 In typical soils of the temperate regions , Cs was taken up about 90 one-tenth as much as Sr, with this ratio decreasing with time to about 23 one twenty-fifth or less after about three years. This suggests more than one cesium storage compartment In the soil. Less strong binding In organic matter has already been mentioned, and observations suggest that a high level of organic matter In the upper layer of some permanent pastures might reduce binding of cesium by clays, thereby enhancing and 23 35 extending Its availability to plant roots to one or two years. * In 137 certain tropical areas Cs was found to be more available to plants 23 than had been expected. Schulz reasons that complementary Ions, In strongly affecting mobility of Ions In the soil as outlined In the preceding section, will 43 in turn Influence uptake by plants. In modem agriculture, nitrogen, potassium, and phosphorus are commonly added to soils. From the complementary ion effect, it would be expected that addition In the forms K and NH^ would liberate considerable amounts of ^-^'Cs into a labile

PAGE 35

23 form for subsequent plant uptake, while the application of nitrogen in 137 the NO3" form would have little effect on the fixed Cs. In an experiment by Schulz, both K"*" and NH^"^ increased the Cs uptake by romaine lettuce but the NH.**" had a much greater effect than K . This was explained by the hypothesis that after the NH^ had released fixed ^^^Cs, microbial oxidation of the oxcess NH^"^ to N03~ removed it from 137 competition with the now labile Cs for plant uptake. Davis agrees that uptake of Cs from the soil is increased by the addition of cesium and cites this as evidence that the capacity to fix 34 cesium in the unavailable form is actually very small. He cites a 137 number of experiments, however, where the uptake of Cs by lettuce, grass, alfalfa, com, millet, and wild plants was decreased by the addition of potassium or was inversely related to the exchangeable level present. In another experiment, added potassium resulted in a decrease in the •''^^Cs uptake by Ladino clover and, as a corollary, the uptake 45 increased as soil potassium was reduced by continued cropping. In this latter experiment, stable cesium added to the soil, even to toxic levels, 137 caused increased Cs uptake in this crop. The collected evidence from the studies cited in this section seems to indicate that complementary ions play a role in releasing fixed cesium from the soil, and that stable cesium added to the soil enhances the overall uptake of •''^^Cs by plants, but that the effect of stable cesium on plant uptake from available ^^^Cs and the effect of potassium on the uptake from the soil are not clearly understood. The effect of soil moisture content is apparently not dear. In studies with beans in soil, limited soil moisture resulted in greater ^^''cs uptake than with ample moisture. On the other hand, Pendleton

PAGE 36

24 speculated in 1962 and again in 1967 that because of the high availability of the nuclide to aquatic and emergent plants, milk and meat from grazing animals utilizing forage from wetlands may contain much more of the nuclide from fallout than such products from drylands, and that the 137 geographic variations observed in Cs content of milk may be, in part, 42 46 a result of different levels of uptake by plants of wfet and dry lands. ' Behavior of ceBium"137 and other radionuclides in plants Cesium and potassium follow similar paths in physiological processes 34 but are not used in an equally competitive manner by plants . Translocation of cesium is more rapid than that of other fission products. Tissue distribution of this element varies with species. When available during active vegetative growth, it goes to the leaves and flowers with 137 smaller amounts going to the seeds. Accumulation of Cs by plants under natural conditions varies considerably among species and with environmental conditions. 137 In 1959, Langham and Anderson speculated that Cs was entering the biosphere via direct contamination of the vegetation rather than via 33 soil contamination and plant uptake. It was soon determined that trace 34 amounts of cesium can be readily assimilated by direct foliar deposition. Russell cites, as well documented, and other authors agree, that direct contamination of plants rather than absorption from the soil is the dominant uptake process for major nuclides, particularly during periods of high fallout.^^*^^*^^ Evidence for this includes the fact that vegetation ^ Cs levels follow seasonal variations rather than being accumulative, with amounts in plants being comparable to deposition during the period of foliage existence. This observation is also consistent with a large discrimination against soil to plant transfer.

PAGE 37

25 Comar refers to foliar absorption of ^°Sr. Russell states that It is necessary to consider both direct foliar retention and "plant base uptake. "^^ He cites evidence that much of this nuclide found on edible leaves is actually absorbed at the basal region in the mat of prostrate stems and surface roots and then transported upwards. In 1964 and 1965, Wykes observed a reservoir of radioactivity in the vicinity of the plant 137 90 base in Upper Midwest grassland when he observed more Cs and Sr per unit mass in the root-mat fraction than in the soil or grass. According to Russell, the amount of foliar deposition is comparable for '^^Cs and '°Sr, but absorption from the soil is responsible for a smaller portion of the ''•^''cs reaching edible tissues than for Sr. He also states that in times of relatively low fallout, the ratio of ^^^cs to 90sr in herbage and milk has decreased. This is evidence for a greater rate dependence relative to the cumulative dependence for cesium than for strontium. 137 Comar suggests that since milk concentrations of Cs (related to levels in pasture grass) have not followed the fallout rate in some areas, it must be assumed that there are also mechanisms for accumulation of previously deposited ^^^Cs.^^ This would be consistent with the earlier mentioned less tightly binding compartment in the organic matter in the 137 soil. Davis predicts that when the stratospheric load of Cs becomes nearly depleted, soil will then become the primary route of uptake. Direct floral contamination is reported as a dominant process for '°Sr absorption in cereals but is negligible with storage organs which grow beneath the soil since there is little downward translocation of strontium and other divalent cations in plants. Comar reviewed reports that ^°Sr accumulates in cabbages mainly by the lodging of rain in

PAGE 38

26 cavities at leaf axils and in potato tubers by the downward leaching by rain over the stem surfaces. The latter represents a means by which 23 imderground tissues can become contaminated from deposition. Neither 137 author makes reference to mechanisms of Cs accumulation in these crops . 137 Johnson and Ward reported the Cs concentration in grain to be 48 much lower than that in hay. Elder and Moore and also Porter et al . reported that pangolagrass (Digitaria defcumbens) and Spanish moss 137 (Tillandsia usheoides) had Cs concentrations much higher than any 49 8 other plants in the Tampa, Florida, area. ' They concluded that the nuclide was surface contamination or weakly bound on the grass but was actively bound on the moss. A ntimber of authors refer to the use of the equation: C o p^F^ + p^Fj with regard to radionuclide levels in plants. Klement cautions that it is an empirical formula and does not necessarily imply understanding of 36 the mechanisms of transfer into and within a system. He makes note of the fact that pj approaches zero for some plants such as Spanish moss and some lichens and that Pj. is near zero for plants sheltered from appreci137 able deposition on foliage. A modified form has been presented for 'Cs in which F2g and pj^, are substituted for F^ and p^, respectively, thus relating concentration to deposition accumulated over the two previous 23 years rather than to the entire history of acc\imulated deposition. 137 This form presumably relates to Cs released by decay of organic material and to the less tightly bound deposition in the organic layer and considers as negligible any uptake of the nuclide tightly bound by the mineral fraction of the soil. Russell also cautions about, the empirical

PAGE 39

27 nature of the expression and emphasizes that aside from the large errors normally Inseparable from field Investigation, deduced relations relate only to climatic conditions and patterns of deposition which prevailed during the surveys or field experiments from which the proportionality J . ^ 35 factors were derived. Ce8ium-137 and other radionuclides in animals Pendleton et al. have briefly summarized literature relating to cesixim 50 and potassium metabolism by animals. Absorption of both cesium and potassium by mammals is large and takes place through the digestive tract. These elements enter the body cells Where cesium is more tenaciously retained; excretion from the body is urinary and in varying degrees, depending on species and diet, fecal. Increasing potassium intake has only slight effect in decreasing body cesium content. According to Davis, the discrlmation factor from foodstuffs to animals (or man) should favor cesium due to preferential assimilation of 3A trace amounts of cesium relative to potassium. Pendleton et al. , citing a number of studies and authors, report that in many animal species the 'Cs/potassium ratio in the body is about two to three times higher than 137 the Cs/potassium ratio in their normal diets (unlike the values observed for the Sr/calcium ratio in animals which are less than one) . 137 Comar reiterates that Cs la efficiently absorbed from the gastro23 Intestinal tract for transport to muscle tissue and milk. He cites literature values for concentration in the muscle tissue of cattle of about 4 per cent of the dally Intake per kilogram and values ranging from 10 to 30 per cent for sheep and pigs . Ward and Johnson quote literature values for cattle which indicate that 1 to 2 per cent of the dally Ingested dose appears in each kilogram

PAGE 40

28 of muscle tissue. Their own work showed Cs levels per kilogram of edible meat leveling off at less than 1 per cent of the daily intake in mature dairy cattle, at 3 per cent in feed-lot cattle, and at 15 per cent in calves. These differences may have been due either to age or 137 feed type. Kreuzer reported a close correlation between Cs in meat of 52 cattle and the methods of feeding and management in Southern Bavaria. The muscle of grazing cattle was more heavily contaminated than that of housed cattle during the grazing season. Change from housing to grazing was reflected in a rapid increase in levels. 137 Kahn et al . , in a study of the effect of feeding practices on ""Cs concentrations in cow's milk, and Porter etal. , in a study of the Tampa 137 lallkshed, reported that 12 per cent of the daily intake of Cs was transferrer! to the daily milk production when the animal is in equilibrium with its diet. * Estimates of the biological half -life of cesium in the cow, the goat, the pig, and the hen fall in the range of 20 to 30 days although some 23 workers report a value as short as 2 to 3 days for the goat. In any event, the turnover in these animals is rapid enough for tissue levels to 137 show little lag in following dietary levels. Retention of Cs in the body is affected by potassium and sodium levels as well as by diuretic action, but these effects appear to be variable and relatively small. Russell noted that an error in the estimate of expected milk levels of ^^Sr was systematically related to the particular fallout history of the preceding year.^^ Taking into consideration the use of stored hay as feed early in the year, he introduced an additional set of terms into the concentration equation: C p^F^ + P^F^ + PiFj^

PAGE 41

29 where F^ la the strontium deposition during the second half of the previous year and pj^ the "lag rate" factor. With this three-term expression, he obtained a much better correspondence of predicted values to observed values. Pendleton et al. state that •'•^^Cs is even more available to organisms living in equatic environments than in terrestrial environments, and, because of the trophic level effect already cited, predacious fish may 50 accumulate this nuclide up to 10,000 times the level in the water. Comar reports that "''^^Cs is concentrated in the flesh of aquatic organisms by a factor of 5 to 20 over that of the surrounding water and Gustafson 137 . ^ ,. ^ rj V 23,54,55 reports high concentrations of Cs in fresh water fish. Cesium-137 in man What has been said about cesium metabolism and distribution and about the Increase in the •'•^^Cs /potassium ratio with the trophic level in animals applies generally to man as well.^*'^° The data of Pendleton et al. indicate that the increase ratio is larger in adult humans than in children. Ceslum-137 retention in humans has been described as multicompartmental function, but many workers have found or believe that a single exponential is a satisfactory expression for most biological purposes. ^^'^^'^^ Reported half -lives for the longer-lived component in adults are on the order of 80 to 140 days. In 1962, Richmond etaJL. measured whole-body retention in four subjects and reviewed the literature. Hardy et al. reported in 1965 on a study of retention of "^^^Cs and ^°Sr following acute Ingestion. In this study, contaminated foods (^^^Cs and ^^Sr, 20 and 60 times higher, respectively, thah in the normal diet) brought back from Rongelap were consumed by a single individual over a seven-day period. In 1965, McGraw

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30 reviewed the collected measurements of the half-time of this nuclide In man and suggested a model for expressing this parameter as a function of 58 59 age. Eberhardt reported a different approach In 1967. Using published data from a variety of sources, he derived an expression for ^^^Cs biological half-life In humans as a function of body weight. The maximum permissible body burden for 'Cs for the occupatlonally exposed, as recommended by the International Commission on Radiation Protection, Is 30 mlcrocurles (pCl) . If one: (1) applies a factor of onetenth for members of the general population, (2) assumes that ceslimi retention can be described with a single exponential function with halflife on the order of 100 to 150 days, (3) assumes an equilibrium situation of constant Intake, body burden, and excretion, and (4) follows the Federal Radiation Council recommendation of assuming that the maximum exposure by an Individual Is no greater than three times the average measured for a population group, then one can derive a maximum permissible dally Intake on the order of 4,000 to 7,000 pCl/day. A value of 4,400 61,62 pCl/day has been used In the literature. 137 Equations have been presented relating dose to Cs Intake and a number of authors have attempted empirically to fit models relating 1' ^els of 59,63-66 137 measured body burdens to measured levels of Cs Intake and thus predict future body burdens from Intake data. Arctic ecosystems I 137 In 1961, Baarll et al, and Llden found unusually high Cs body 67,68 burdens In people In Norway and Sweden, respectively. These Initial findings led to further studies which suggested that unique ecological situations exist with regard to radionuclides in the fallout-food-man 69—72 chain in arctic regions. Although these regions have less

PAGE 43

31 137 fallout than many other areas of the world, levels of Cs In arctic inhabitants are among the highest documented. High htiman body burdens have been traced primarily to the influence of ecological factors upon fallout accumulation in the lichen-caribou(or 73 74 reindeer) -man chain. ' Lichens represent a most important reservoir of ^^^Cs and other fallout radionuclides because of their longevity (decades, even one century), persistence of aerial parts, and their dependence upon nutrients dissolved in precipitation. This effective 1 07 retention of Cs by lichens, the importance of lichens as a winter food for caribou, and the dependence upon caribou and reindeer for food by 137 many northern peoples has resulted in this important Cs concentration 75,76,77 process. * ' In the United States, studies of radionuclides in the arctic food chain were addressed initially to questions associated with the proposed 78 Project Chariot site located near Ogotoruk Creek in northwestern Alaska. Since 1963, surveillance activities have continued and expanded in 79—84 Alaska. The Battelle-Northwest Laboratory has studied the body burdens of "'"^''cs in northern Alaskan residents (especially in Anaktuvuk 85 Pass) since the summer of 1962. In April and May of 1965, the USPHS expanded the geographic area 137 73 investigated by measuring Cs body burdens throughout Alaska. Radiation dosage received by the average adult Anaktuvuk Pass Eskimo from ^^^Cs body burdens during 1964, the year of highest values, was estimated at 135 to 150 millirem (mrem).^^ This value is about 30 per cent less than that amount serving as a Radiation Protection Guide for population groups during normal peacetime.

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32 Ettvlrdnmeiital Radioactivity Meaduremetits in Florida Environmental radioactivity sampling and measurement within the State of Florida began with the collection of samples In 1957 by the Of. Florida State Board of Health, Bureau of Sanitary Engineering. ° This soon led to a statewide program of sampling and gross alpha and beta radioactivity analyses of surface and underground water resources , sediments, raw and finished water from water supplies, and sewage plant 2-5 Influents and effluents. Some soil, aquatic organisms, and rainfall were also Included In this early sampling. Gllcreas, Morgan, and Vreeland reported the establishment In 1957 of a routine program Involving regular monitoring of gross alpha and total radioactivity of air and rainfall at the University of Florida and of surface and underground waters In 87 88 89 Alachua county. ' ' The results of these sampling programs are 2—5 86—90 reported In a number of publications . ' The University of Florida program also Included twice yearly sampling and gross alpha and total87,88,89 activity analyses of plants, animals, and soil. As a consequence of an agreement with the USAEC, the USFHS established the Radiation Surveillance Network In 1956 with nationwide stations 91 92 for sampling of dry deposition (later discontinued) and air. ' In 1957, the network was expanded and precipitation sampling was added. One station was designated at Jacksonville under the operation of the Florida State Board of Health with five to seven continuous precipitation and 24hour air samples collected per week, in 1961, a second station was established at Miami. In 1960, the Florida State Board of Health established similar air and precipitation sampling stations at Orlando, St. Petersburg, Tallahassee, and Pensacola; the six stations became known collectively as

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33 2 the Florida Radiation Surveillance Network. Florida data from the state and national networks are reported in the various issues of Report, 2-5 of Florida Radiological Data . In 1963, air sampling stations were also established at Titusville, Cocoa, and Melbourne in the vicinity of 3 Cape Kennedy. In 1953, the USPHS established the National Air Sampling Network— a survey of airborne particulate pollution, including gross beta radio93 ^ activity, in urban and non-urban areas in the United States. One 24-hour sample is ordinarily taken every two weeks; sampling frequency was increased at many stations during time of anticipated increases in airborne radioactivity due to fallout. Stations are designated for operation either yearly or during alternate years on a staggered schedule. During the period 1959-1964, stations operated every year both at Tampa and in the Florida Keys and on more selective schedules in Jacksonville, Miami, Orlando, and St. Petersburg. Results were regularly reported in Radiological Health Data . ^^ Precipitation sampling was added at designated stations with the cooperation of the United States Weather Bureau in 1959. These included a station at Tampa beginning July, 1960. A station of the 80th Meridian Air Sampling Program was established at Miami in June, 1957.^* This network of stations near the 80th meridian (west) was established in 1956 by the United States Naval Research Laboratory with the assistance of the USAEC, the United States Weather Bureau, and interested groups in Canada and South America. The stations sampled ground-level air for measurement of radioactivity using a variety of experimental collecting devices. In 1957, all stations were supplied with filter samples and blower units, and the network was expanded to Include locations of Interest to the United States Air Force Cambridge

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34 Research Center. It was operated in 1958 and 1959 as part of the International Geophysical Year Program on Atmospheric Nuclear Radiation and continued from 1960 through 1962. with a reduced number of sampling sites. ^**^^ Individual samples were analyzed for gross beta radioactivity and samples were composited monthly for analysis for a variety of specific nuclides. Reports of results and 80th meridian concentration §5 profiles from 1959 on appeared regularly in Radiological Health Data. Lockhart et al. summarized the results for 1957-1962 and included a complete list of reports (26 references) resulting from this program 94 96 during that time period. * The TJSAEC Health and Safety Laboratory (HASL) deposition sampling program, in operation since 1958, employs two methods of collection for ^°Sr analysis. In the "pot" method, precipitation and dry fallout are collected for a period of one month in an exposed stainless steel pot and transferred to a bottle for shipping, while in the "column" method precipitation and dry fallout are collected in a polyethylene funnel connected to an ion exchange column which is capped for shipment after a one-month collection. A station utilizing a pot collector is in operation at Coral Gables. Operational responsibility for the 80th Meridian Air Sampling Program was transferred from the Naval Research Laboratory to HASL as of January 1, 1963, to be run in conjunction with the fallout sampling program. ^^ Concurrent with this transfer, gamma analyses , both totalgamma activity and activity above 1 million electron volts (MeV) energy, were substituted for gross beta analysis as the initial means of sample evaluation. Ion exchange collectors for deposition sampling were added to the stations not having them. This resulted in the initiation of a

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35 column collection station at Miami In July, 1963, In addition to the Coral Gables pot station. Results of the 80th Meridian Program since 1963 and of the deposition sampling are reported In HASL technical reports, and summaries have been published periodically In Radiological 28 Health Data . The USAEC and the United States Department of Agriculture have been conducting soil sampling, first Individually and then jointly, since 1955 90 99 100 to determine world-wide distribution of Sr. ' During this course of sampling, collections have been made at both Miami and Jacksonville. The Appalachlcola River at Chattahoochee and the Escambia River at Century have both been sampled under the USPHS National Water Quality Network (currently the Federal Water Pollution Control Administration's Water Pollution Surveillance System) . This program was established in 1957 for sampling surface waters of major United States river basins for physical, chemical, biological, and radiological analyses. Weekly grab samples are collected for analysis at a central laboratory for gross alpha and gross beta activity in suspended and dissolved solids . Analyses are performed on either weekly samples or monthly composites, depending upon the amount of radioactivity expected. Strontium-90 analyses have been performed on selected quarterly composltles from each station since 1959. Results have been reported for the Appalachlcola River for 47 one-month periods between April, 1960, and June, 1965, and for the Escambia River for 39 such periods between May, 1961, and May, 1965. In 1961, the Water Supply Activity, Interstate Carrier Branch, Division of Engineering and Food Protection of the USPHS, established a Drinking Water Analysis Program to gather extensive data on the radio102 activity content of water supplies on Interstate carrier?. Results

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36 have been reported for two samplings each at two water plants in Fort Lauderdale, two water plants in Miami, and a plant in Tampa during the period, 1960-1963. In addition to the studies of radionuclides in milk already mentioned, a special study conducted by Consumers Union in July through August, 1958, included Miami among 50 North American stations from which 90 103 milk samples were collected for Sr and stable calcium analysis. In describing shellfish radioactivity research. Lackey reports the total background activity of oysters collected at two locations in Florida in March, 1958. Gross alpha and gross beta determinations and gamma spectra were reported for analyses performed by the USPHS on oysters, fish, shrimp, crabs, and other biota, as well as on salt water and silt collected periodically during January, 1962, through January, 1963, from 2 several locations in Brevard County, Florida. In summarizing results for a variety of food samples, Straub et ^. reported Sr and stable calcium levels for one sample each of radishes, turnips, and t(imlp greens from Florida, all collected from Cincinnati, 105 Ohio, markets in 1959. In 1959, 1961, and 1962, the Miami area was Included in the USPHSaponsored Consumers Union studies of Sr, Cs, and other radionuclides in a typical diet of teenagers. * These studies were carried out periodically between 1959 and 1964 in a number of cities in the United States . Florida samples have been included in the United States Food and Drug Administration's studies of radioactivity in domestic and Imported food 2,3,108 and animal fodder.

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37 Fifty-six Florida vegetable and citrus samples, collected January through March, 1964, by the Florida Department of Agriculture, were 4 analyzed for specific nuclides by the Florida State Board of Health. The USPHS Institutional Diet Sampling Network, established in January, 1961, with 8 locations, was extended to 21 cities, including Tampa, in October, 1961. ' Twenty-one meals plus snacks (three meals per day for seven days) are collected each month at a participating school or other institution in the respective cities. Solid food, dairy products, and wastes are analyzed as separate portions at USPHS regional laboratories. Results are reported in terms of weight consumed per day and concentration and daily consumption of calcium, potassium, phosphate, 8trontium-89 (^^Sr) , ^°Sr, iodine-131 ("H) , "^Cs, barium-140 (l^Ofia) , 226 and either total radium or radium-226 ( Ra) . These results appear 28 pp-r
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38 has a layer spacing not favorable for "structural absorption," (3) that the uptake of '^^^Cs by this soil in a slurry test was much less than that reported for other soils, (4) significant uptake from the soil by grasses transplanted to this soil, (5) different rates of uptake with Bahlagrass, reaching an equilibrium level more rapidly than pangola, and (6) that the more slowly equilibrating pangola showed an Indication of progressing toward an equilibrium level about 30 per cent higher than that of Bahia. The first sampling of a third grass, Bermuda, showed levels that indicated either a much lower equilibrium level than the other grasses or a slow rate of uptake. However, retarded growth prevented further sampling. Unfortunately these authors did not report radioactivity levels in these grasses prior to transplanting. Reports of monitoring sewer effluent, air, surface water, and milk for tritium in the environs of the USAEC's Pinellas Peninsula Plant near 30 St. Petersburg have appeared periodically since 1960. In 1965, tritium levels were also reported for precipitation collected at Ocala during 1961 , 112 and 1962 as part of a global tritium distribution study. Hartgering described a worldwide sampling program in 1955 and 1956 to estimate human exposure by analysis of 24-hour urine specimens for 113 Isotopes of iodine, strontium, and cesiiim. Participants were five to ten personnel at each of a number of military installations, which Included McDlll Air Force Base, Tampa. Radioactivity of humans has been measured at a number of installa137 tions. In some of the published reports of "'Cs measurements in humans at the Walter Reed Army Institute of Research, average concentrations have been tabulated by states. * The average of six determinations on Florida individuals during 1958-1959 was not noticeably different from

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39 114 averages in other parts of the country at that time. In addition, the average ^^^Cs levels and number of subjects were reported by quarter for Florida subjects for six quarters during 1960 and 1961 (a total of eight Florida subjects) .'''^ Seven Florida subjects were also identified as having been included in the United States averages for" July, 1963, through August, 1964. Cesium-137 measurements have been made in humans at the University 117 of Florida, but results have not yet been published. It was announced to the press that a whole-body counter survey was to be made of residents in the Tampa institution participating in the Institutional Total Diet 118 Sampling Program, but no published reports were found to date. Undoubtedly, subjects from Florida have been counted at other installations even though specific Florida results have not been reported in the literature. Current environmental radioactivity mea surements in Florida Current sampling in Florida for radioactivity analyses is shown in Figure 3. At the present time, gross alpha and total radioactivity measurements continue to be made regularly at the University of Florida on 119 samples of air, precipitation, sewage, water supplies, and surface water. 114 ^ \, Monitoring also continues routinely on a statewide basis. The Tampa Pasteurized Milk Network Station collects weekly milk samples; the two Radiation Surveillance Network Stations at Jacksonville and Miami continue regular operations. The Florida Radiation Surveillance Network Stations continue to collect air and precipitation samples, and the State laboratory analyzes these samples for gross beta activity. The statewide grab sampling of surface and underground waters and of water supplies continues

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40 Alachua Cduntv Surveillance ; (University of Florida) Air and precipitation (one station), surface water, water supplies, sewage Cape Kennedy Vicinity ; Air, soil, water, vegetation KEY: Radiation Surveillance Network: r~1 Air and precipitation Florida Radiation Surveillance Network : O Air only ^ Air and precipitation A Cape Kennedy Vicinity: Air 4h Pasteurized Milk Network X HASL Fallout Program: Deposition, pot collector Deposition, column collector Air (80th Meridian Station) Regions indicated are for Florida raw milk sampling Not shown; Statewide water sampling Shellfish sampling Turkey Point Vicinity ! Air, water, soil, vegetation FIGURE 3, CURRENT SAMPLING PROGRAMS IN FLORIDA FOR ENVIRONMENTAL RADIOACTIVITY ANALYSIS

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41 for gross alpha and beta analysis. Grab samples of shellfish are submitted to gamma-spectrum analysis, and then they are ashed and analyzed for gross alpha and beta activity. Raw milk samples are currently being collected on a statewide basis for combining into six regional composites 90 for gamma spectrum and Sr radiochemical analyses. In addition, several special monitoring projects are underway in 120 the State. A cooperative plan has been drawn up by the United States Air Force, the USPHS, and the Florida State Board of Health to collect environmental samples in the vicinity of Cape Kennedy for radioactivity analysis. Air is being sampled for gross alpha and beta analysis at Fort Pierce, Orlando Air Force Base, McCoy Air Force Base, and New Smyrna Beach; the three previously mentioned state-operated stations at Titusville, Cocoa, and Melbourne function as part of this program. Soil, edible vegetation (including citrus) , and non-edible vegetation are being sampled regularly and submitted to gamma spectral analysis, while water is collected and submitted to gross alpha and gross beta analyses of both the dissolved and suspended solids. Samples from the 12 sites within the first 10-mile radius of the area are analyzed by federal laboratories; samples from the 10 stations in each of the two 10-mile annuli beyond this are analyzed by the Florida State Board of Health Radiological Laboratory . A special sampling program is also being carried out by the Florida State Board of Health near the site of the planned nuclear power plant at Turkey Point, a facility due to go into operation in the early 1970' a. ^^° Eighteen sites are sampled on a rotating basis; six are sampled per month so that each site is sampled quarterly. Analyses are similar to those for the Cape Kennedy off-site area.

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42 Results from the Miami and Coral Gables stations of HASL's air and fallout sampling programs were included in the latest reports of these programs , and results were reported for the environment of the Pinellas Peninsular Plant of the USAEC as recently as February, 1967, 30 95 97 implying that both these programs are currently in operation. ' ' Cesium-137 and Other Radionuclides in Selected Environmental Media Mfethodoldgv and Findings As will be discussed in more detail in Chapter III, the earlier observations on radionuclides in Florida milk and feeds and the preceding review of cesium ecology and Florida radioactivity measurements led to the selection of meat and vegetables as the major items of study with 137 nuclide emphasis on Cs. Although this study is intended to investigate levels and patterns of radioactivity in specific media, the ultimate significance of the findings lies in the influence of the observed levels on human radioactivity intake. Methods of evaluating dietary intake as reported in the literature can be grouped into three general categories: (1) evaluation of individual food items and, if all components of a total diet are evaluated, subsequent computation of total dietary intake, (2) analysis of the composite total diet of a real or hypothetical individual, and 121,122,123,50 (3) analysis of urine and feces. Cesium-137 in individual food items Meat sampling usually involves selection of some particular muscle, portion, or product for analysis. It has been reported that the concen137 124 tration of Cs can vary from muscle to muscle. Fredrikason et al . reported considerable variation in the rate of cesium uptake between different muscles with the most active muscles taking up cesiim most

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43 125 readily and the inactive muscles ultimately reaching a higher content, 137 Ekman reported that the half-time of Cs varies between tissues, helng longer, for example, in skeletal muscle than in most other organs or tissues . 137 On the other hand, in a study of uptake and fate of Cs in rats, cattle, sheep, swine, and poultry. Hood and Comar report that the most striking feature of cesium distribution in tissues was the constancy of the pattern, both between individual and species and between the various . ,. . ^ 127 tissues of the body. 137 Data reporting environmentally occurring levels of Cs in meat or animals in the United States axe limited; some of the first data was from animals maintained in the vicinity of nuclear testing sites. Cesium137 levels were reported for unspecified muscle from cattle sacrificed in 1957 and 1958 from herds maintained in the vicinity of the Nevada Test Site, and another reference was made to cattle sacrificed before and after 128 129 the 1961 "Gnome" underground nuclear test in New Mexico. ' 137 The United States Department of Agriculture has reported Cs and Sr levels of beef rib meat surveyed in 1960 and beef soup stock surveyed 130 in 1961. The following year bologna and frankfurters were surveyed for ' Sr only, and the results were not significantly different from those reported earlier in rib meat. Plummer recently reported very little difference In concentrations 137 of naturally accumulated Cs between various muscles of the Georgia while-tailed deer; this prompted him to use the tongue as an estimator of 131 137 general body levels, Mlettlnen reported 1960 and 1961 Cs levels in 72 reindeer, potatoes, and certain other food items of Finnish Lapps. He reports that there is an error of only a few per cent when analyzing the 90

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44 shoulder of the reindeer as representative of all consumed tissues. He estimates losses of activity in meal preparation to be about 10 per cent, but he does not make a corresponding correction in his calculations. In a highly detailed study in the United States, Ward and Johnson reported "'"^^Cs levels in beef from dairy and feed lot cattle at Fort 51 Collins, Colorado, in 1963. They found no differences, within limits of counting statistics, in content between 12 retail cuts from the same animal as measured on four different beef animals. They concluded that, while greater precision in counting may have shown statistically significant differences between areas of the carcass, these would be small 137 compared to the effect of differences in the Cs contamination of the various animals* diets. Straub reported surveys in which individual vegetable crop samples 90 137 collected from markets in 1958 were analyzed for Sr, Cs, and other gamma-emitting radionuclides. Food categories reported include fruits, fruit juices, meats, leafy vegetables, root vegetables, legumes and corn, and rice. Setter et al. reported an elaborately planned survey of individual 132 133 food items. * Market sampling was performed simultaneously with a food consumption survey for six quarters beginning July, 1962. Selection of samples was based on varieties and amounts of food available at the time of sampling as indicated by the United States Department of Agriculture marketing reports and local marketing data. Categories included meat , -vegetables , fruit, and potatoes. During the six calendar quarters, ground chuck beef was sampled for four quarters and lean pork for two, lettuce for four and cabbage for two, and apples for four and oranges for two; potatoes were sampled for four quarters. Results for

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45 ^^^Cs and ^°Sr were reported for each of seven regions and the whole of 137 the United States. The lowest Cs levels vere found In lettuce, cabbages, potatoes, apples, and eggs. These authors stress that Identification of food from production areas is difficult because of factors such as: (1) centralized marketing, (2) raising of the majority of poultry feed in one region, and (3) raising of beef in one region for fattening in another on feed from a third. Highlights of the United States Food and Drug Administration's program of measuring radioactivity in individual domestic and imported human and animal food items included: (1) a call in 1954 for food packed prior to the nuclear era, (2) a subsequent program of gross radioactivity analysis, (3) gross beta activity measurements on a broad basis 90 137 , 131 ,«,« 108,134-138 since 1958, and (4) emphasis on '"Sr, "^'''Cs, and •^^^I since 1960. 137 90 Under this program, results of one Cs analysis and about 100 Sr 2 3 108 analyses were reported for Florida samples collected in 1962 and 1963. * * Laug reported that in this program samples were mostly raw agricultural products, usually unwashed and unpeeled, and generally in the condi138 tion in which they were found in the warehouse or store. For the purpose of data summarization, samples were assigned to classifications such as vegetables, brassicae, root vegetables, white potatoes, com, and fruits (including tomatoes, cucumbers, pumpkins, and squash, as well as the berries, citrus, and other tree fruits). Cesium-137 levels were generally five times as high as ^°Sr levels. Vegetables ranked in Cs coptent from highest to lowest as follows: leafy vegetables, dairy products, brassicae, root vegetables, fruits, com, and white potatoes, Laug also states that, although the first year following the resumption of atmos90 pherlc tests was not marked by dramatic increases of Sr in foods.

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46 sporadic higher concentrations were noted In leafy crops. Fallout concentrations were reported to be higher In the eastern and central United States than In the West, an effect believed to be associated with rainfall. In an experiment with a leafy vegetable and one kind of brasslcae, 137 commercial processing (washing and canning or freezing) reduced Cs by 20 per cent. 137 The Florida State Board of Health determined and reported Cs 95 and zirconlum/nlobltim-95 ( Zr/Nb) contents of 56 leafy, non-leafy, root, brasslcae, and miscellaneous vegetable samples and fruit samples that had been collected by the Florida Department of Agriculture In 1964. 137 90 Bruce reported the levels of Cs and Sr found In milk, meat, root vegetables, and leafy vegetables In the United Kingdom during 1962139,140 1964 and In milk and meat during 1965. Ceslum-137 levels In meat from cows, sheep, and reindeer In Norway were reported by Hvlnden for the 141,142 period 1959-1965 and by Madshus for 1964-1965. Madshus took the precaution to collect all samples from the semitendinous muscle when 142 137 sampling meat. He also reported average Cs levels by zone for potatoes and carrots for the fall of 1964. These two Items were chosen for sampling because of universal production. DeRuyter and Aten estimated 122 Intake by humans In the Netherlands by sampling urine and feces. Between November, 1964, and March, 1965, they also sampled some Individual food items, including milk, grain products, kale, and brussels sprouts. Uptake of '''^'^Cs by some leafy vegetables should be similar to grasses and legumes. Porter et al. and Cromroy et al. , in the studies reviewed earlier, reported Cs levels in grasses and animal feeds collected near Tampa, Florida. ' Csupka published Cs levels for grass and alfalfa in Western Slovakia during 1962-1965, and Wykes reported levels of this 143 47 nuclide in grass in Minnesota in 1965. *

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47 The highest "^^'^Cs levels in lean tissue samples in the United States are those reported by the National Center for Radiological Health in a program of monitoring unspecified muscle from Alaskan caribou and 82 137 reindeer during 1962-1966. Pendleton etal. reported Cs levels that were measured in mule deer meat by gamma cotintlng the hip to knee 50 portion of skinned hind legs. Ceslum-137 in the total diet A number of total diet studies conducted in the United States are pertinent to this research because they report nuclide levels in individual food items or categories, Illustrate how food items have been classified into categories, or report effect of food on total Intake for the area and time represented. In the Consumers Union total diet study, diets representing the total diet of teenagers for a week in the particular sampling region were prepared by home economists from produce purchased in local markets, and 144 the composites were submitted for analysis. Reference has already been made to the Tampa station of the National 109 Institutional Diet Sampling Network. Cesium-137 Intake levels at this station have been among the highest in the network, a condition which is not inconsistent with high milk levels in that area and the fact that dairy products are one of the major contributors of this nuclide. Reports are available for the January through June, 1966, portion of this study. 145 Baratta and Williams have made comparisons between these two studies. They traced differences in observed levels of Intake to differences in amounts of food consumed in each study. In addition to the program of sampling raw food items, the Food and Drug Administration has a total diet study. '•^^''•^^•^^^ Sampling in this

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48 program Includes 82 food Items in the 11 categories of the food plan recommended by the United States Department of Agriculture as nutritionally adequate at a moderate cost level for boys 16 to 19 years of age (the highest intake group of the United States population). Items are sampled in amounts proportional to consumption as reported in the 1955 Household Food Consumption Suirvey. Samples are collected at designated cites (none in Florida) in the United States. The categories include leafy vegetables, smooth vegetables, root vegetables, potatoes, dried beans, 137 fruits, and meat and eggs. The most recent report Includes Cs levels in the total diet at nine cities for February through November, 1965. In March of 1960, the USAEC instituted a diet study in a single 149 city. This program was later expanded to three stations and it became known as the Tri-City Diet Study. In this study of the typical 90 adult diet, foods are grouped and analyzed in 19 categories with Sr and •^^'Cs levels reported in each category for each city. Categories include meat, poultry, fresh fish, shellfish, eggs, fresh vegetables, canned vegetables, root vegetables, potatoes, dried beans, fresh fruit, canned 137 fruit, and fruit juiies. At Chicago, analyses of these samples for Cs have been performed quarterly since 1961. At the other two stations, these analyses were performed at the end of each year through 1964 and then quarterly in 1965. Reports for each city include yearly quantity intake, nuclide concentration, and yearly nuclide intake for each food 137 category and daily and percentage of total Cs intake attributable to the five overall categories of milk, meats, cereals, fruits, and 150 vegetables. Thompson and Lengeman draw attention to the fact that estimates of quantity of food consumed do not match the precision of the laboratory

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49 123 radionuclide measurements. By use of different available consumption estimates, they show how estimates of intake based on the same laboratory data can vary as much as 75 per cent. 137 In spite of this potential difficulty, Rivera reported that Cs body burdens calculated from intake data were in relatively close agree64 ment to measured body burdens. He suggested that diet analysis was a useful means of predicting body burden. He also stressed the need for better analytical techniques and more frequent food measurements. Using Cs/potasaium ratios as a basis, Gustaf son examined the 65 relation between diet and human body burdens. He concluded that diet corresponded to in vivo data when the former was transformed by a factor of 3.0 and advanced in time by four months. In the same report, he extrapolated the human body burden to the end of 1966. 137 The factor of 3.0 used by Gustaf son to transform diet Cs/ potassium ratios to correspond with body burden levels is consistent with the trophic level effect discussed earlier. The four-month time advance used in this transformation is probably related to time required by the human body to equilibrate with changes in the diet and may also be related to storage of food before constimption. The Federal Radiation Council developed predictions of the expected 39 40 radionuclide levels in the diet in 1963-1965. ' Since then, measurements of radionuclides in milk, the total diet, and humans have been reviewed for the years 1963-1965 and compared to the Council prediction 61 62 estimates for these years. * In addition, levels for 1966 were predicted using the approach proposed by the Council. The observed values were in agreement with the predictions; the peak of intake by population groups appears to have occurred in 1964.

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50 Other g^imha-emittlng radionuclides In addition to ^^^Cs and ^°K, food and vegetable samples are commonly analyzed In the various surveillance programs In the United 131 States by gamma spectroscopy for any or all of the nuclides I, cerlum-lA4 (^^^Ce) , manganese-SA (^ V) , ruthenium/ rhodlum-106 ( Ru/Rh) , zlnc-65 (^^Zn), and ^^Zr/Nb; by gamma spectroscopy or radiochemical methods for ^*°Ba or barium/ lanthanum-140 (''•^^Ba/La) ; and by chemical or ^ . X . . -1 AA «^ 226„„ 78,105,106,109,110 emanation methods for total radlimi or Ra, ' The Institutional Diet Sampling Network samples are analyzed for potassium, ^^^Cs, total radium or ^^^Ra, ^*°Ba, and ^^"'•I. However, In reports for 1966 the latter two were reported to be below detectable levels. Zlrconlum/nloblum-95 was reported for reindeer and caribou muscle In 1964.^^ Manganese-54, ^^Zn, ^°^Ru/Rh, and cerlum/praseodynlum14A ('^^Ce/Pr) were reported In lichens, mosses, sedges, and other plants 78 In Alaska during 1959-1961. As was noted earlier, the Florida State Board of Health reported levels of ^^Zr/Nb found In Florida vegetable 4 samples In 1964. The presence of Zn,_a neutron activation product, was reported In a variety of foods collected In 1958-1959 and attributed to high 151 altitude fallout by Murthy et al. It was reported by Van Dllla In , 152 1960 In beef liver, beef muscle, hamburger, and milk. Manganese-54 was reported In human and bovine liver In 1965 and In freshwater clams In 1966 by Sax and Gabay, and In the Netherlands diet in 1964-1965."'-"*>"^ I Antlmony-125 ("'"^^Sb) was reported by Svensson and Llden In forest moss In 1965 and by Johnson etal. In Colorado forage In the years 19621965. ^^^''^^ DeRuyter and Aten tentatively Identified trace amounts of

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51 both ^^^Sb and beryllium-7 in leafy vegetables in the Netherlands In 122 1964-1965. Ce8ixiin-134 was identified in 1960 by Krieger and Groche as a 157 neutron activation component of fallout from some weapons tests . During the period 1960-1964, it was found in air samples, elk, milk, wheat, and beef in the State of Washington and in caribou and reindeer 72 81 158 159 meat, fish, and human inhabitants in the arctic. ' ' * This nuclide was thought to have xd.de distribution and to have been produced prior to 1961. It was present at the level of about 1 to 2 per cent of the "'Cs levels. Traces of sodium-22 ( nSa) have been reported in vegetables in the conterminous part of the United States in 1964; in fallout, herbage, milk, and total diet samples in Italy in 1962-1964; in elk, bass, milk, wheat, beef, and human urine collected in the State of Washington during 19631964; and in moose ^ caribou, and reindeer meat as well as human urine and 158,160,161,85 Eskimos in Alaska in 1963-1964. Perkins and Nielsen suggest that a considerable amount of Na was generated during 19611962.^^ DeBortolli et al. show evidence that this nuclide is taken up 161 from the soil rather than being deposition rate dependent. The activation product, iron-55, has been reported in arctic and subarctic food chains and residents, and in the blood of residents of the State of Washington. * The low energy X-ray, 5.9 thousand electron volts (keV) , emitted by this nuclide does not interfere with the spectra of other nuclides previously discussed and probably would not be detected by 85 a conventional counting system used to analyze for these others. Nuclear testing will add fresh fission products to those observed in environmental samples. Klement reported that transient increases in

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52 air and precipitation radioactivity were observed following the French nuclear tests of February and April, 1960, but that debris from these events added not more than 0.1-0.2 per cent to the total worldwide fallout of long-lived fission products. lodlne-131 and Ba were found in air, precipitation, forage, and, in some cases, milk following the Chinese nuclear tests of October, 1964, May, 1965, and May, 163,164,165,156,166 1966. The Florida State Board of Health reported a very pronounced increase of several days duration in the gross beta 4 activity levels of air in seven Florida cities following the 1964 test. Following the 1965 test, gamma analysis of air samples in the United 131 States showed I, tellurium-132 , molybdenxim-99 , and neptunium-239 in addition to •'^'I and "'^^Ba/La.-'-^^ Naturally occurring radionuclides of the uranium and thorium series may also be present in environmental samples. In 1960, Muth et al. 167 reported the radium content of various foods in Germany. Either total 226 raditm or Ra is also reported for several of the total diet sampling programs in the United States. ' In reporting a study of gamma activity in a variety of plants in the states of Kerala and Madras in India, Minstry et al. published vegetable ash gamma spectra that very clearly showed activity from thorium series nuclides as the principal component. Klement reviewed the literature in 1965 and reported 170 sources and typical levels of natural radionuclides in foods . Analytical methods Analytical methods vary from laboratory to laboratory and are characterized by a combination of innovation and standard physical, chemical, and radiochemical procedures.

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53 Two of the laboratory systems handling large numbers of environmental samples, the Health and Safety Laboratory of the USAEC and the laboratories of the National Center for Radiological Health of the USPHS have issued analytical reports and manuals in a readily available 171-182 form. 137 Boni has developed a ntmiber of procedures for analysis of Cs 183,184 ^ ^ and other radionuclides in environmental samples . Other papers on the analysis of environmental samples by gamma spectroscopy have been 185,186 ^ ,„,, published by Ward, Johnson, and their associates. In 1966, Mercer reviewed analytical methods and corresponding references for ^ , 187 measuring radioactivity in food and other biological materials.

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CHAPTER III EXPERIMENTAL APPROACH The programs of monitoring radionuclides In Florida milk have 137 Indicated that Cs levels In Florida milk have characteristic geographic patterns with unusual levels In much of the State. These patterns and 90 levels are particularly striking when compared to those of Sr. Reports of additional Investigations of this situation Indicated that 137 the levels of Cs In Florida milk are directly related to levels of Intake of this nuclide by the animals and that high levels In milk are due to elevated levels In one or more types of locally grown forage. The findings reported for milk suggested that an unusual radloecologlcal situation exists In Florida. This suggestion In turn prompted a study of (1) the extent to which these \mxisual levels and characteristic 137 patterns of Cs extend to other media and Involve other nuclides, (2) the Influence of environmental radioactivity on human radiation exposure In Florida, and (3) some of the reasons for unusual environmental radionuclide levels In this state. Selection of Media for this Study Various media were examined with respect to the following characteristics: (1) their role In the food chain, (2) their distribution In the State, (3) the Importance of their economic role, (4) their capacity for concentration of radionuclides, and (5) their likelihood of becoming contaminated. As a result, lean beef and vegetables grown for human consumption were selected for sampling. 54

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55 . Since cesium follows metabolic pathways in animals similar to those of potassium and is preferentially concentrated by animals, animals and 137 animal products are important sources of exposure to Cs. Beef and milk are among the most important animal products produced in Florida. Milk is an important source of hxnnan exposure to radioactivity; dairies are distributed throughout this state, and the dairy animals receive a large portion of their feed from local pastures and locally grown forage. However, milk was not considered in this investigation because it is already being routinely sampled on a statewide basis and is currently being studied in detail at the farm level. In contrast, there have been no reported studies of specific radionuclides in Florida meats. In fact. Ward and Johnson referred to the 137 51 paucity of any information on Cs levels in beef . Since high levels of ^^^Cs have been reported in forage in parts of the State, beef animals deriving a portion of their diet from these forages will have correspondingly high intakes of this nuclide. Since ingested ^^'^Cs is distributed throughout the tissues, particularly the muscle, and because beef is an important part of the human diet, this commodity is potentially a signifi137 cant source of Cs intake in this state. Other animal products produced in Florida for human consumption include poultry products and pork. However, in this state chickens and other poultry are commonly raised in batteries off the ground and are fed grains and supplemental feeds largely brought in from outside the production areai Consequently these animals receive little feed from the immediate environment. Hogs receive a variety of prepared feeds as well as refuse and scraps, but, since Florida is a "grain-poor" state, much of the hog feed is also imported. Because of the feed sources and management

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56 practices, poultry, egg, and pork radioactivity levels would probably show little relationship to the factors influencing the milk levels that originally Instigated this study and therefore were not studied in this investigation. From the fact that certain animal forages grown in Florida appear to 137 have unusual levels and distinctive patterns of Cs, it might be predicted that other vegetation grown under similar conditions of exposure to deposition and uptake from the soil would have similar patterns of this nuclide. Vegetables are an important commercial crop in this State (400,000 acres, production valued at over $250,000,000 in the 1965-1966 production year), they are consumed directly by man, and some 188,189 vegetable crop or another is produced statewide. Although occasional Cs analyses of Florida vegetable samples have been reported in the literature, there have been no systematic, statewide studies. Selection of Beef Sampling Stations A program was drawn up to sample animals raised at the Florida Agricultural Experiment Stations with supplementation where necessary by samples purchased directly from slaughter houses or butcher shops. Beef sampling stations are described in Table 2 and shown in Figure 4. The beef sampling program was based on information obtained by consultation with the director of the University of Florida Meat Laboratory. "^^^ Within the Florida Agricultural Experiment Station system, beef animals are fed at seven sites within the State. Five of these sites are identified in Table 2 as Stations 1, 2, and 3; Station 4— Source 1; and Station 7. Beef animals are also fed at the Animal Nutrition Laboratory in Gainesville but none were killed during

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57 the course of sampling in this study. In addition, beef research is getting underway at the West Florida Station at Jay, but no animals were available for slaughter during the course of this study. TABLE 2 BEEF SAMPLING STATIONS Station Number

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58 6. GRACEVILLE Experiment Station Sources Other Sources FIGUBE 4. BEEF SAMPLING STATIONS

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59 case of the station near Quincy, animals are slaughtered at a local packing plant In that city, but even these are graded by the director of the Meat Laboratory. The sampling of experiment station animals has the advantages that: the majority of the samples are available from a single source, the identity of the carcass is maintained through the slaughter house, and detailed records are available if needed. These records identify the history and description of the animal, the feeding program, and the weight and grade of the carcass. In contrast, slaughter house animals are frequently bought at auction and mixed together in holding pens and carcass identity is not maintained, both of which make it difficult to identify the source and history of any sample collected. This is not of concern if the sole object of the study is to determine the average radionuclide exposure to the public from meat marketed at a particular point, but it does present a problem when it also is desired to relate meat activity levels to specific locations and feeding practices. Beef Sampling Since random sampling from certain feeding experiments could have resulted in the sampling of bulls far in excess of the small number appearing in retail cuts on the market, the restriction was placed that bulls were to be eliminated from sampling. A further restriction was placed that samples were to be from "control" animals or from those on the experimental diets most closely resembling the feeding practice of the particular area. In sampling from butcher shops or commercial slaughter houses, samples were taken from meat on hand at the time, and special care had to be exercised to receive samples from animals that had been locally grown.

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60 This was no problem In the several cases where samples were collected from country butchers who fattened their own beef. Sex, breed, and age were not considered as variables In this experiment, but these and other factors were recorded where available for possible future use in investigation of any unusual or particularly interesting results. It was assumed that the distribution of different samplings from a station (often different experiments in the case of experiment station samples) and the method of selection would produce samples representing the average and range of radioactivity levels in fattened beef raised under various "typical" Florida conditions. Sampling in May, 1966, of two carcasses from each of two experiment stations confirmed the feasibility of the mechanism of sample procurement. Indicated the sample size necessary for analy8l9, and tested the sample preparation, the analytical, and the computational procedures. The main beef sampling took place during the period January through 137 June, 1967. After part of the samples were collected, the Cs/potassium ratios were examined to help determine the total number of samples to collect. Inspection of the data suggested a trend with highest values in the southern and central parts of the State and lowest in the northwestern part. It was assumed that the "within stations" variance for all 1967 samples would not be greatly different from that computed for all samples collected up to that time (1966 and 1967) and that the final 1967 station means would not be greatly different from those obseirved up to that time. Estimations were then made of sample sizes necessary to show selected statistically significant differences. Although inspection of the available data suggested differences between stations, it was found that, with the assumed variance, at least

PAGE 73

61 six samples per station would be necessary to conclude that any of these differences is statistically significant. Vegetable Sampling To minimize possible bias introduced by crop differences, stratified sampling was employed with samples collected within each of three categories (strata): (1) leaf and stem, (2) fruit, seed, and pod, and (3) root and tuber. This categorization is generally consistent with the one used by the United States Food and Drug Administration to summarize results of analyses of individual vegetables and with the food groupings used in the total diet studies described in the literature review. If sufficient numbers of samples are collected in each category, an examination of category effect is also possible. Sampling was further stratified within these categories by specifying a total of 12 crop classifications to be sampled wherever available. These classifications, shown in Table 3, were set up by selecting and combining from the approximately 20 different vegetable crops grown in 188,189 significant quantities in Florida. Selection was based on the amount of production and availability in the State, following consultation with a vegetable crops specialist from the Florida Agricultural Extension Service. Acreage figures taken 189 from published reports are also included in Table 3. The only highacreage crops not included in the sampling were sweet com and watermelons. The com presented technical problems in the collection and preparation of sufficiently large samples of the edible portion, and the watermelons are seasonal in nature and represent only a small portion of a person's yearly intake. The principal harvest season for most vegetables is between October and June. 188,189 Preliminary sampling was carried out in May and June,

PAGE 74

62 1966, to test the feasibility of the sampling mechanism, to develop and test sample preparation, analytical, and computational procedures, and to deteinnine the size of portion and counting time necessary to detect existing levels of radioactivity. Full scale sampling took place between January and July, 1967. TABLE 3 VEGETABLE SAMPLING Acreage-'-^^ Harvested in 1965-66 Category Crop Where Grovm Season No. ofl88 Areas Where Grovm Leaf, Stem Lettuce, endive, escarole, romaine 8 12,100 Celery 5 12,200 Cabbage 11 14,500 Greens many not reported All Leaf, Stem 13 without greens Fruit,

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63 the niauber of samples to a reasonable level, the State was divided into regions and each station"was assigned to an appropriate region. Initially the State was arbitrarily divided into four regions of approximately equal area and designated as Southern, Central, Northeast, and Northwest. The data itself, however, began to suggest that more homogenous regions would result if the lower east and west coasts were assigned to separate regions, This resulted in the regional designation shown in Table 4 and Figure 5 and identified as Southeast, Southwest, Central, Northeast, and Northwest. Sequence of Study Following sampling, the work was pursued in five stages: 1. Determination of kinds and levels of gamma radioactivity in the selected media, 2. Determination of variations in media, geographic location, and points in time, 3. Identification of unusual levels of gamma radioactivity in these media and development of hypotheses concerning causes and mechanisms involved, 4. Investigation of the interrelationships of the kinds and levels of radioactivity in various media, and the relationships with other available parameters, 5. Estimation of the effect of these nuclide levels on the radioactivity in food products, and in turn, on human radionuclide intake and radiation exposure.

PAGE 76

64 I S CO S cocacnStocoScocnlSScncocncnMcocncocotncaco Id g M 01 U a Id 0) u •d 5 M H M (d M • ^ o Id n pq 13 S u » U u H SmmMMMCQHH aa(oa)aiua)o)iH fiM MJ3 ^ B ja M Xi u 4J4J74J4J4J4J4J4J4J ooooooooo 4J U 4J 4J 4J 4J4J4J4J'U4J^4J a)(uSa>^3> a d VI M M 0) 0) o o o . _4J4J4J4JU4J^4J'U OOWOOOOOOOO OTMCOOTCOOTCOCOWUUUtSSKSSSUSiZiSIBSS^SS^ HHi-IHHHHHHHCMCMCMCsievlCMN

PAGE 77

65 Stations adapted from major production areas designated by University of Florida -gg Vegetable Crops Specialists. SOUTHEAST REGION FIGURE 5. VEGETABLE SAMPLING STATIONS

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CHAPTER IV ANALYTICAL PROCEDURES AND EQUIPMENT Beef Sampling The standard procedure for beef sampling was to sample two animals from each group of animals. The most notable exception was the sampling of six animals at one time at Qulncy, where there was only one slaughter of experimental animals during the course of this study. Three pounds of lean muscle were requested per sample; a total of 5 pounds was requested when the sample contained untrlmmed bone and fat. In sampling experiment station animals, samples were selected from the first two carcasses hanging In the cooler which met the restrictions of the sampling design (Chapter III). Samples In this case consisted of the portion associated with the 13th rib (3-4 Inches of short loin) from either side of the carcass. This portion could be collected without seriously affecting the marketability of a hanging carcass. In sampling other animals, It was not always possible to sample this portion or Identify the portion sampled, particularly when samples were obtained through cooperating Individuals. Special samples from a packing plant at Station 4 (discussed In Chapter V) were collected In the cutting room from animals selected by packing plant personnel. When picked up in the shipping department, the samples were not identified as to the portion of the animal. Other samples were cut from unspecified lean portions of carcasses of locally fed animals on hand at the butcher shop or packing plant at the time of siEUhpllng. 66

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67 Vfegfetalblfe Sampling Samples were collected both directly from farms and from markets. A large proportion of the samples were obtained through the cooperation of the Chemistry Division of the Florida Department of Agriculture, which has an extensive program of sampling and analyzing agricultural products for pesticide residue. The remainder of the samples was obtained directly by the investigator, who visited both farms and markets, and through the assistance of volunteers, who collected and shipped in samples. Vegetable samples were requested to be market samples that had gone through a washer or were in a condition suitable for washing in the laboratory. Portions of at least 3.5 kg of edible portion (8 pounds) were requested. If a large enough single portion were not available, a sufficient number of smaller portions from the same area were composited to make up a sample of the required size. All samples were identified by area where grown and, if possible, by farm or nearest community. Vegetable samples received from the Florida Department of Agriculture laboratories were collected according to standard procedures of that department. '^'^*^^^ Briefly, field samples were composited from five portions, each collected from different parts of the field. Market or packing shed samples were composited from portions taken from a number of crates in order to represent the lot or originating field. These samples were then sub-sampled at the Department laboratory for analytical purposes, and the excess portions after sub-sampling were made available for this study. Some of the Department procedures call for quartering heads of leafy samples such as cabbage and lettuce with analysis of opposite quarters. When the original sample did not include sufficient heads to provide unquartered heads for this study, unused quarters were provided. In the

PAGE 80

68 case of a small number of samples , the entire sample was sliced before sub-sampling and the sliced excess provided for this study, in these cases, the possible effect of unwashed samples had to be considered in evaluating the data. Field samples collected directly by the investigator or by volunteers were collected in essentially the same manner as those received from the Florida Department of Agriculture. Market samples collected by these individuals consisted of 8 to 10 pounds of produce selected from that on display at the market at the time of sampling. Market samples were collected only if the area where grown could be identified. B6ef Sample Preparation Beef samples were prepared for analysis by boning, trimming the excess fat, and grinding the lean portion twice through a 3/16 inch (in.) grinder plate. Vegetable Sample Preparation In general, analysis of vegetable samples was performed on the whole of the portion corresponding to the particular category being examined (leaf and stem; fruit, seed, and pod; or fleshy root and tuber); samples were not peeled, cored, or shelled. Tips were not removed from bean pods, and seeds were not removed from squash and peppers. The entire portion analyzed was edible although not always eaten. Unless already washed when received, vegetable samples wera washed under running tap water, using a stiff bristled brush where necessary to remove clinging dirt. They were then drained dry or blotted with a turkish towel to remove excess moisture. After washing, samples were chopped into smaller pieces if necessary and triturated with either a meat grinder or a blender. About 1 milliliter (ml) of 40 per cent

PAGE 81

69 formaldehyde per 100 grams of finished sample was added as a preservative. The tap water used for washing was checked periodically for radioactivity to assure that washing did not introduce significant radioactivity. More specifically, tops were cut off turnips, rutabagas, and other root vegetables at the top of the fleshy root, and stems were removed from hard skinned squash. These vegetables were washed and cut where necessary and then ground in two passes through a meat grinder with a plate with 1/8 in. holes. Stems were removed from cucumber, peppers, soft skinned squash, and tomatoes; they were then washed, dried, chopped, and blenderized. The outer leaves were removed from the cabbage head, the base of the head was cut off, and the remaining portion was then chopped and blenderized. Some cabbage was received as quartered heads; these quarters were trimmed along the cut faces before chopping to remove dirt and dehydrated material. On the few occasions when untrimmed bunches of celery were received, they were topped near the center of the leaf cluster, and the upper portion was discarded; a portion of the base of all bunches was cut away. Individual stalks of celery, collards, and turnip, mustard, and other greens were separated from the bunches and washed, drained, blotted, chopped, and blended. It was necessary to scrub with a brush to remove clinging dirt at the base of the stalk. Collards presented a particular problem in that they were very tough and required considerably more distilled water for blending (up to 1,000 ml per 3.5-liter (1.) sample) than did other vegetables. Heads or bunches of salad greens such as lettuce, romaine, escarole, and endive were cut in halves or quarters which were then further

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70 separated into clusters of a few leaves for washing, blotting, chopping, and blending. The equjipment used In sample preparation Is Identified In Appendix A. Several different pieces of power equipment were tested for first stages of sample reduction, but, since these devices had to be borrowed and returned for each batch of samples. It was deemed more convenient to prechop by hand with a butcher knife and cutting board. In grinding, samples were precut only to a size that would pass Into the grinder, ground material was collected In tared containers, the required amount of preservative was added and hand mixed, and the amount of preservative and the net weight of the sample were recorded. The first step In blending was to weigh the washed, dried, and prechopped ssimples In a suitable container. A portion of the weighed, prechopped sample was then Introduced Into the blender along with the least amount of distilled water necessary to get blending action (none In the case of tomatoes and cucumbers; about 200-500 ml In the case of other vegetables) . Once blending action started, larger pieces of the sample were Introduced £ind additional distilled water was added only If necessary. The net weight of sample added to the blender was computed and recorded after taking the tare weight on the container. Any added water was measured and recorded by volume; unit density was assumed. The weight of blended material (sample plus water) was calculated and the required amount of preservative was added to and blended with the sample. Preserved samples were transferred to labeled wide mouth plastic jars and held for analysis. Dilution factor due to added water and preservative was calculated ztnd recorded for future use In calculating nuclide concentrations .

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71 Ganma Radioactivity Counting Individual pieces of equipment are described In Appendix A. Gammaradloactlvlty analyses were performed with a multichannel scintillation spectrometry system. The detector was a stainless steel clad 4-ln. by 4-ln. right cylindrical sodium Iodide (thallium activated) crystal coupled to a phototube. The detector was located In a shield 20 In. by 20 In. by 24 -In, high (Inside dimensions) with 2-ln. thick lead walls, floor, and cover and with a 30 mil cadmium and 5 mil copper lining. Signals are analyzed by a 400-channel pulse height analyzer calibrated to 10.0 keV per channel. Samples were loaded to the full mark In prewelghed polyethylene Marlnelll beakers, and the loaded beakers were weighed and placed over the detector In the shield. Two counting configurations were used; a 3.5-llter beaker was used for vegetable samples, and a 1.0-llter beaker was used for meat samples and vegetables of less than 2 liters In quantity. Samples between 2 liters and 3.5 liters In quantity were diluted to 3.5 liters. Normally, samples were counted for 50.0 minutes; some of the samples at the beginning of the study were counted for 100 minutes. At least two analyses, usually on the same or consecutive days, were performed on each lean beef sample. All the vegetable samples were given an Initial count, and about two-thirds of these samples were recounted after 50 to 100 days. The delayed second count helped confirm the tentative Identification of any short-lived activity and permitted recounting of the longer-lived activity In the presence of much reduced levels of the short-lived activity. Gross (background plus sample) spectra for Individual samples and a background spectrum for the particular counting period were digitally recorded for computer analysis and future reference. Backgrounds were

PAGE 84

72 also subtracted from the individual counts in the analyzer memory, and the oscilloscope displays of net spectra were inspected visually for the presence and relative size of peaks. The net spectra of all original counts and selected recounts were also recorded with the x-y plotter for future visual reference. Interpretation of Gamma Spectra A gamma spectrum, as developed on a multichannel gamma spectrometer, is a frequency distribution of counts registered in particular energy increments. Gamma rays are emitted by radioactive atoms at one or more discrete energies characteristic of the particular nuclide. However, because of the nature of the interaction process and the limitations of the instrumentation, gamma-ray photons of a single energy do not show a "line" spectrum at the output of the spectrometer system but rather show a continuous spectrum with an approximately Gaussian-shaped distribution (photoelectric peak) corresponding to absorption of the total energy of the photon plus a lower energy portion (Compton continuiim) corresponding to smaller fractions of the total photon energy. In addition, the spectrum may show effects related to the configuration of detector and shield, such as backscatter peaks or escape peaks (peaks lower than the principal peak by the amount of energy carried Way by X-rays escaping from the detector) and may also show secondary peaki corresponding to additional photon energies emitted by the nuclide. ) The resolution or width of the photopeaks tlie shape of, and area-^nder, the Compton portion of the spectrum relative to the photopeak^ and the importance of backscatter and escape peaks are functions of configuration and composition of the particular sample, detector, and surroundings.

PAGE 85

73 The number and energy of specific photopeaks are utilized in identifying specific nuclides. The quantity of nuclide in a particular sample is determined from the area under some portion of the spectrxim (such as the photopeak portion) . The counts in a selected region are summed, and a conversion or "efficiency" factor, appropriate to the nuclide, sample configuration and counting system, is applied to convert this sum or area to the amount of nuclide in the sample. In the case of a mixture of more than one gamma-emitting nuclide in a sample, the spectrum reflects all of the contributors and is assumed to be a linear combination of the individual contributors. Because of the limits of resolution (width of the photopeaks) , additional peaks at other energies, and the Compton portion of the Individual spectra, some members of the mixture will contribute counts in the region of, or in some cases even obscure, the principal peaks of various other members of the mixture. In this study, gamma spectra were first inspected visually for the presence, location (energy) , and relative size of peaks and then were evaluated by a computational procedure. Computational procedures for interpreting gamma spectra were reviewed in the manual recently issued by the National Center for Radiological Health. '^^ The method used in this study is the one described as the "Simultaneous Equations Method." This method was chosen for a nuinber of reasons. It was the method most familiar to the investigator at the time of the beginning of the study and it was being used ±n a la.rge number of public health laboratories at that time. This method la less subjective than the less elaborate stepwise nufl.ide-by-nuclide "stripping" method, and errors in the estimation are not compounded successively in one

PAGE 86

74 direction as severely as when stripping is performed. In addition, it is less sensitive to instrument instability than some of the more sophisticated methods and once the initial simultaneous calibration equations have been solved, computations can be performed with a calculator or even by hand if necessary. Briefly, in this method the interferences between some nimiber (N) of contributors to a composite spectrum are corrected for by setting up and solving a system of N simultaneous equations involving the unknown contributions of the N nuclides in terms of counts in the photopeak regions. The original equations are developed from counting a standard ^ of each of the nuclides separately with the system and in the configuration to be tised for the unknown samples. Once the simultaneous aquations have been solved to yield explicit equations for each nuclide, these same latter equations can then be used for all subsequent sample computations until such time as the system needs recalibration. A computer program for calibration computations was written in FORTRAN II and later converted to FORTRAN IV for use with the University of Florida IBM 709 computer. This program reads the conditions of the calibration and the counting data for the various standards. It then averages any replicate counts for the same nuclide, computes the matrix corresponding to the coefficients of the simultaneous equations, inverts the matrix in order to obtain the coefficients for the explicit equations, and computes counting efficiency (counts per disintegration) in the photopeak region for each of the nuclides. Identifying information, the computer coefficients , and computer efficiency are printed out and all the necessary calibration Information is also punched on cards for subsequent use in computations. For performing the subsequent

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75 sample calculations, a program was written in FORTRAN II, later converted to FORTRAN IV for the IBM 709, and also converted to FORTRAN IV for use with the University of Florida IBM System 360 computer. This latter program reads in the calibration coefficients and efficiencies and reads the background counts and sample gross counts for each sample. It then computes and writes out the concentration and the associated two-standard deviation counting error of each specified radionuclide in terms of disintegrations per minute and pCi per unit (weight or volume) .

PAGE 88

CHAPTER V BESULTS OF BEEF SAMPLING Individual samples were collected from 45 animals at seven different stations.* Duplicate analyses were performed on the lean portion of each of these samples with repeat duplicate analyses on one sample for a total of 92 lean beef analyses. Four of the samples were collected from two stations during the preliminary work in May, 1966, and the balance were collected between January and June, 1967. A departure from the original plan took place when samples were collected at Station 4 from several groups of animals that were obviously not fed to the same degree of finish as the majority of the animals. The data from Station 4 are given special consideration in this presentation of results. The major gamma-emitting nuclides observed in the beef samples were ••^^Cs, ^°K, and 226^^ and its decay products, bismuth-214 (^•'•^Bi) and lead-214 (^ Pb) . Quantitative computations were made for Cs, K, and ^^^Ra in equilibrium with its daughters. It was necessary to include the latter activity in order to correct for the interference with the determination of ^^^Cs and potassium by the ^'•^Bi that occurred in a large number of the beef samples. No particular significance is placed on the quantitative values for radium and daughters since there was no assurance that equilibrium actually existed and, indeed, no attempt was *, ''The single sample collected at Station 6 consisted of lean stew meat from the farm's retail outlet and although it was counted here as one animal, it may actually have represented more. 76

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77 made to prevent the loss of the gaseous radon-222 intermediate. Ceaium137 is reported as pCi/kg of wet weight and as picocuries per gram of potassium (pCi/g K) . Since essentially none of the potassium is contained in the fat, the latter method of reporting compensates for variations in the completeness of trimming of the fat. On the other hand, it obscures the effect on -^^^Cs of fat distributed through the lean. Cesium-137 Content of Lean Meat from Grain-Fed Beef. 1967 A summary of Cs concentration, potassium content, and Cs/ potassium ratios of lean meat from grain-fed Florida beef sampled in 1967 is shown in Table 5 and in Figure 6. There is an apparent gradual decrease in '•'''cs content from south to northwest. The highest station average was 296 pCi/kg (78.8 pCi/g K) at Ona and the lowest station average was 105 pCi/kg (31.8 pCi/g K) at Pensacola. The highest individual value, 539 pCi/kg (133.6 pCi/g K) , was also found at Ona and the lowest Individual value, 55 pCi/kg (16.3 pCi/g K) occurred at Pensacola. The statewide average of all samples was 214 pCi/kg (54.4 pCi/g K) . 4J 0) M 0) a-^ O "H 0) 60 (0 u I 80-. 60, 40. ;.P 20-No. of Samples: ' Station No. Average of 8 samples from 1966 and 1967 FIGURE 6, CESIUM-137 CONTENT OF LEAN MEAT FROM GRAIN-FED FLORIDA BEEF~1967

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78 m « o* en

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79 137 The effect of geographic location on Cs content of lean meat from grain-fed Florida beef was tested by performing an analysis of 137 variance on the Cs/potassium ratios reported for the samples at the five stations from which the full complement of six samples were collected (Stations 1, 2, 3, 5, and 7). This anzilysis, presented in Table 6, shows that, at the o = 0.01 level, there is sufficient evidence to indicate a location effect. TABLE 6 CESHM-137 CONTENT OF LEAN MEAT FROM GRAIN-FED FLORIDA BEEF, 1967— EFFECT OF GEOGRAPHIC LOCATION (EXPRESSED AS CESITJM-137/POTASSIUM RATIO) ANALYSIS OF VARIANCE Source Degrees of Freedom Sum of Squares Mean Square Stations

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80 indicate a significant difference between stations, but all stations in the group are significantly different from Station 5. The "northern" stations (5, 3, and 7) constitute a similar group, differing significantly from Stations 1 and 2. The inability to establish the significance of any smaller differences in station means is due to the high variation within stations. It is possible that by increasing the number of samples per station and/or by reducing the within station variance (such as blocking on some variance contributing characteristic not identified here) more of the apparent station differences could be demonstrated to be statistically significant. TABLE 7 RANKING OF FIVE FLORIDA BEEF SAMPLING STATIONS ACCORDING TO CESIUl^-137 /POTASSIUM RATIO OF LEAN MEAT BASED ON 1967 SAMPLES, SIX GRAIN-FED ANIMALS PER STATION Station Average pCi/g K

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81 137 Inspection of the data suggests a trend of highest Cs levels in the southern part of the State, intermediate in the central and northeastern part of the State, and lowest in the far western part of the State. Statistical testing of the data supports the hypothesis of a location effect and supports the hypothesis of a systematic geographical trend to the extent that the data can be grouped into two overlapping groups of adjacent stations. Ef fact Of Year of Collection Two samples each were collected at Station 1 and 2 during May, 1966, and six samples each were collected at the same stations during 1967. As shown in Table 8, the two stations appear to show temporal trends in opposite directions, so that any overall year-to-year difference is insignificant, at least for the amount of data available. TABLE 8 EFFECT OF YEAR OF COLLECTION ON CESIUM-137 CONTENT OF LEAN MEAT FROM GRAIN-FED FLORIDA BEEF

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82 Effect of Feeding Program and Meat Otialltv 6n Cesitim-1 37 Levels After cancellation of a scheduled kill of experiment station animals at Station 4, an attempt was made to obtain alternative samples from animals grown In the same general area. It was not possible In the time available to obtain samples that were of the same quality of meat as those obtained from experiment station animals and that were positively Identified as locally fed. It was possible to obtain four samples from a local packing plant consisting of unidentified cuts from four locally fed animals. This meat was Intended for grotmd beef and meat products (frankfurters, bologna, etc.) and was of a much lower quality than meat which Is usually sold as retail cuts. These animals, slaughtered In April, 1967, were Identified only as "two had some grain, two fed II* primarily grass." As shown In Table 9, two USDA GOOD samples collected In January, 1967, from two steers fed com and citrus pulp on an experiment station dry lot In this same general area had •"'^^Cs levels of 20A and 142 pCl/kg (54.3 and 42.6 pCl/g K) , respectively. Reference to Table 5 shows that these values fell within the general range of all the "eastern" samples. 137 By contrast, the four packing plant samples had Cs contents ranging from 293 to 12,500 pCl/kg (90.4 to 3,710 pCl/g K) . Two of these animals had ^^''cs levels that were of a general magnitude about equal to (ranging from one to two times) those of the other "eastern" samples and the other two had levels 10 to 100 times as high. It was suspected at this point *. ''comments by the packing plant manager on the feed of these and subsequent animals from this source were probably based on Inspection of the condition of the animals and quality of the meat.

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83 1 OT that the higher levels of Cs in the meat were due to animal diets composed primarily of grass. Several weeks later, four additional samples were obtained from the same packing plant along with as much identifying information as obtainable in order to further investigate this source of meat. As shown in Table 9, all of these animals were cows of varying breeds, the meats were of low grade, and again two samples were identified as from grass fed animals and two from animals that had received some grain. A range of results very similar to the first four samples was 137 obtained, with the totally grass-fed animals having the highest Cs levels.

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84 o o o o IT) CO O O Sf ON CO CM H H iH r^ +1+1 +1+1 O 0% 1^ CM a\ o o\ yo +I+I+I+I r* 00 o o vO O CO •* in 00 m 00 •H -rl -O •« nj ra 0) 0) M M IM IH 00 00 I I n n to CO U U 'A O O CO CM H m >n m m

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CHAPTER VI RESULTS OF VEGETABLE SAMPLING A total of 165 vegetable samples were collected, analyzed, and evaluated for gamma-emitting radionuclide content. Of these, 29 were collected during the preliminary sampling in May and JUne, 1966, from six different stations in four regions. The remaining 136 were collected during January through July, 1967, from 19 stations in the five designated regions. As summarized in Table 10, the 1966 samples represented 10 different crops and the 1967 samples represent the 12 designated crop classifications . The principal radionuclides detected in vegetable samples in addition to ^°K were ^^^Cs and naturally occurring Ra and its daughters. Following the arrival of fresh fallout, presumed to be from Chinese nuclear weapons tests, short-lived nuclides (half-lives on the order of one week) appeared briefly and moderately long-lived activities (halflives ranging from one month to one year) appeared and gradually diminished. Cesium-137 results are considered first in this chapter, and a consideration of other nuclide results follows. *Crops, categories, stations, and regions are defined in C3hapter III. 85

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86 TABLE 10 NUMBERS OF FLORIDA VEGETABLE SAMPLES ANALYZED FOR GAMMA RADIOACTIVITY BY REGION, CATEGORY, AND SAMPLING PERIOD Year. Category 1966 Leaf, Stem Fruit, Seed, Pod Root. Tuber All Categories 1967 Leaf, Stem Fruit, Seed, Pod Root. Tuber All Categories 1966 & 1967 Leaf, Stem Fruit, Seed, Pod Root. Tuber All Categories •STRegion TJT 3

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87 TABLE 11 CESIUM-137 CONTENT OF FLORIDA VEGETABLES SUMMARY BY SAMPLING PERIOD AND REGION

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88 The ^^^Cs content of the 29 samples from 1966 averaged 61 pCi/kg (wet weight) while the 136 samples from 1967 averaged 58 pCi/kg with an overall sample average for all 165 samples of 59 pCi/kg. The data suggest a geographic trend with maximum values in the regions designated Southwest and Central, the lowest values in the Southeast, and Northwest, and intermediate values in the Northeast. The apparent regional effect was tested for the 1967 sampling period with an analysis of variance. Examination of the data showed that the variance increased in a general fashion as the mean increased and that frequency distributions of sample means were skewed to the right. Both observations suggest that in spite of other sources of variation, the analytical results were strongly influenced by the behavior of radioactive decay, which can be described by a Poisson distribution (variance equal to the mean). Accordingly, in order to stabilize the variance, the data was transformed for the purpose of the analysis of variance by taking the square root of the reported sample means. From this analysis, shown in Table 12, it can be seen that there was sufficient evidence at the a » 0.01 level to indicate a regional effect. The Scheffe procedure was used to test the transformed data to 19A determine which of the regional averages were significantly different. As is shown by the ranking in Table 13, the central, southwest, and northeast regions constitute a group for which there is insufficient evidence to indicate a significant difference between regions, but all of these regions are significantly different from both the northwest and southeast regions. The northeast, northwest, and southeast regions also constitute a similar group, differing significantly from the central and southwest regions.

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89 TABLE 12 CESIDM-137 CONTENT OF FLORIDA VEGETABLES, 1967 SAMPLES EFFECT OF GEOGRAPHIC LOCATION ANALYSIS OF VARIANCE (SQUARE ROOT TRANSFORMATION) Source Degrees of Freedom Sum of Squares Mean Square Regions Within Regions Total 4 131 135 618.50 2,134.91 2,753.41 154.63 16.30 9.49 kitic ***, Significant at the a = 0.01 level. TABLE 13 RANKING OF FIVE FLORIDA VEGETABLE GROWING REGIONS ACCORDING TO CESIUM-137 CONTENT, 1967 SAMPLES (SQUARE ROOT TRANSFORMATION) Region Central Southwest Northeast Northwest Southeast of 14 31 37 25 29 8.87 5.83 4.30 3.78 Number of Samples Average VpCl/kg 9.28 Solid lines Indicate regions showing no significant difference at the a a 0.01 level.

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90 Effect of Year of Sampling on Ceslum-137 Levels In Florida Vegetables Although there was Insufficient data collected In 1966 to analyze the effect of both regions and years In a two-way classification, It still 137 would be desirable to know If the average Cs levels In vegetables changed over the two years. In addition, It would be desirable to combine the data from the two sampling years In order to provide more Information per unit when the effect of Individual stations, categories, and crops Is examined. In columns four and five of Table 14, the two years are compared within each of the regions In which sampling was conducted both years. There Is not a great difference In overall averages of all samples, but when the data Is examined within Individual regions, there Is a suggestion of region-year Interaction, with a possible decrease with time In the southeast region, a possible Increase with time In the southwest and central regions, and no apparent difference In the northwest region. The difference between sampling periods was tested within each region as shown In columns six through nine of Table 14. A series of "t"-te8ts was performed on the transformed data using the pooled estimate of within years and regions variance. This provides a simple method of comparing years when there Is Insufficient data for a two-way classification. However, It must be kept In mind that In using successive "t"-tests, the chance of concluding there Is a difference when none actually exists Is compounded to a higher probability than Indicated by the o level employed. From Table 14, It can be seen that, with the method of testing employed, there Is Insufficient evidence to conclude a difference between years In the southeast, southwest, and northwest regions, even at the a » 0.20 or greater level.

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91 TABLE 14 COMPARISON OF CESI13M-137 LEVELS IN FLORIDA VEGETABLES 1966 AND 1967 SAMPLING PERIODS Rei^lon

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92 Ce8lum-137 Content of Florida Vegetables— Other Obaervatlona The results of ^37cg ^gre also briefly examined with regard to such factors as collection station, vegetable category, and crop. Since various combinations of these factors were not sufficiently represented by the,, data, it was not possible to employ statistical testing to examine the results in greater detail than in the preceding sections. This does not prevent inspecting the data for apparent effects and trends. However, in doing this some of the observations will be based on relatively small numbers of samples and effects of the various factors will not always be completely separated. Category effect In Table 10 , page 86 it was seen that not all categories were equally represented in determining regional means; this arrangement could bias the determination of regional effect if there actually were significant category differences. Average ^^^Cs levels are summarized by both region and category in Table 15 for each sampling period, and the corresponding ranges are summarized in Table 16. When 1966 and 1967 are considered as the single period, the statewide averages of samples within categories are almost identical for all categories and thus do not suggest a category difference. If all regions are weighted equally and category averages are computed by 137 averaging regional averages within each category, a possible higher Cs level is suggested for the "fruit" category. This is due primarily to the high "fruit" average for the central region and must be viewed with a certain amount of reservation since this particular average is based on only four samples.

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93 m p ^^ «

PAGE 106

94 iH vO CO H lO •*

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95 Examination of individual category averages within regions does not suggest any consistent pattern. Even if there were a category effect which was not accounted for in the test of regional differences, the regional averages within categories , presented in Table 15 and superimposed on Figure 8, suggest that the same regional trend shown for all samples combined is also shown within each of the categories. Station effect Individual station averages for the combined years, 1966 and 1967, are presented in Figure 8. This figure shows the relative uniformity between station means within each of the regions and supports the rationale used to group adjacent stations into geographical regions. The portion of the figure for all samples regardless of category suggests that, with the possible exception of Station 13, no other grouping of adjacent stations into a small number of geographic regions could have produced more uniformity of station averages within regions. It may be noted that the average for Station 13 was based on only one sample which by itself does not appreciably affect the regional mean. The uniformity of stations also holds generally, although with greater variation, within each of the categories. Crop effect Regional average ^^^Ca levels for each crop are shown in Figure 9. This fiLgure shows that, whenever a crop was sampled In a sufficient ntmber of regions to make a comparison, the same general trend exists within crops as was shown within categories and as was shown for all samples combined. Deviations from the general pattern appear primarily to involve crop-region classes which have only small numbers of samples.

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96 00 A! 0) 0) 00 «D M 0) Region Average 200-150-100-50-No. of .^ Samples; 200 + 15010015 1 I All Samples 50 No. of Samples : 200+ 150100. 50 No. of Samples ; 2 hslo J5|< 200 -150 10050_. No. of .i««*« Samples ; 13 Q 15 614 117 Leaf. Stem pd 300 • •••• rlzUlofTizm Fruit. Seed. Pod rri...2 7 410 in** T^ ^ Root. Tuber n E ^2' station Region I SE omo SS S sw 10 j^l2 03" 16"26 NE I23j, 25 NW FIGURE 8. CESIUM-137 IN FLORIDA VEGETABLES, aASSIFIED BY SAMPLING STATIONS WITHIN CATEGORIES, 1966 AND 1967

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97 Figure 9 also supports the decision not to consider a category effect when region differences are analyzed. Although some crops appear to be consistently higher than the others, these crops fall in ^1 three categories and there is considerable crop-to-crop variation within each category. In Figure 10, the data are arranged by crop within region. This figure shows that the crops with the highest levels of activity (statewide average greater than the overall average of 60 pCi/kg) were cabbage, greens, tomatoes, cucumbers, and potatoes. In this figure, it is also shown that these are the crops which exceed the respective regional averages for all crops in the greatest number of regions. Greens were consistently above the particular regional average in all regions. Cabbage was high in the central and southern part of the State but not in the northern part where most sample levels were frequently less than the associated counting error. The high overall tomato average was due primarily to the high averages at the two southwest stations where the tomatoes were sampled. Cucumbers were above the regional average in three of the five regions where they were sampled and the cucumber average was strongly influenced by two high samples at Station 10. Potatoes were above the regional average at each of the four regions where they were sampled. Unusual samples Individual results ranged from no detectable activity In a number of samples to several high samples exceeding 300 pCi/kg. Individual high samples are Hated in Table 17.

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98 0) to M 0) o u LU

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99 Region Average 100 . 50 •• No. of Samples ; 60 •H 0) 60 loose. .^o. of • Samples; t4 m 0) 0) 00 « M 10050" No. of ,. Sai^noles ; Statewide fi4l U g» y ra 14 M 14 JUiL m-raSoutheast Region 'l;1"?;''m''T'*ln''ifi';ni' 228*1'^ 10050No. of Samples; loose No. of Samples ; S-o riL ' p-irzis Southwest m * Region fl JZL 300 in Central Region OOP — r— M Northeast Region 0^ t^ \r[ [A\ 8 fl 100 SONo. of Samples: • "6 o"ffi"1-6l";i^'--f^"fyr"m-"y-'t7l"rrT"rnr" Northwest Region a) « u >> M u 9 t( «d g *J H ^ 0) 01 0) (d v< >J o o u Leaf. Stem u o o. Ck. 0) (0 Fruit. Seed. Pod Root. Tuber FIGURE 10. CESIUM-137 IN FLORIDA VEGETABLES ^, CLASSIFIED BY CROPS* WITHIN REGIONS,' 19(66^ AND 1967

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100 TABLE 17 CESIUM-137 LEVELS IN FLORIDA VEGETABLES, HIGH INDIVIDUAL SAMPLES

PAGE 113

101 of computation and correction for interferences with other nuclides, these nuclides were considered to be in equilibrium with the Ra parent and calibration was performed with such an equilibrium mixture. These nuclides were included primarily in order to correct for interferences with other nuclides by the gamma rays of numerous energies emitted by this decay series. As in the case of the beef samples, no particular significance has been placed on quantitative values for this decay series because no attempt was made to assure equilibrium in the sample. Mangan6a6-54 Manganese-54 (314 day half-life) was included in the calibration mixture because it has been reported in vegetation samples in recent years and because it was found in forage and Spanish moss samples by this laboratory in 1965. However, essentially no Mn was found in either 1966 or 1967 in vegetable samples in this study. Fission products other than cesium-137 Iodine-131 and •'*°Ba/La (8.05 and 12.8 day half -lives, respectively) were not detected in the 1966 samples. However, this does not conclusively demonstrate the absence of these nuclides since any quantities originally present could have undergone considerable decay in the 50-60 days that elapsed from collection to analysis of these particular samples. Both of these nuclides were found in the majority of the lettuce and greens samples collected during January 15-18, 1967. Barium/lanthanum-140 was also identified in some of the greens samples collected February 14-15, 1967, but no ^^"""I was detected at this time and neither was found at the next collection one week later or any time thereafter. Ruthenium/rhodium-106 (1.0 year half-life) was not detected in 1966 samples, but activities identified as ^^^Ce/Pr and ^^Zr/Nb (285 days and

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102 65 day/35 days, respectively) were found in nearly all 1966 lettuce and greens samples which were collected May 21-24, 1966. Zirconiuin/niobiuni-95 and activities tentatively identified as Ce/pr and feu/Wi were found in nearly all the lettuce and greens samples collected January 15-18, 1967, in the majority of this type of samples collected February 14-15, 1967, and in a small number of samples collected February 22, 1967. These activities were found in essentially none of the samples collected after February, 1967. These fission products were found in all parts of the State which were sampled during the indicated time periods. However, these activities were observed very rarely in other leaf and stem crops such as celery or cabbage or in fruit, root, or tuber crops. Recounting after a decay period frequently showed a greater reduction in the activity designated as ^^*Ce/Pr and •'•^^Ru/Bh than could be accounted for by radioactive decay alone. This observation suggests that a portion of the activity attributed to these nuclide pairs may have been due to the shorter-lived ^^•'•Ce and ''•^^Ru (32.5 and 40 days half-lives, respectively) which are also found in fresh fission-product fallout.

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CHAPTER VII DISCUSSION OF RESULTS 137 Five aspects of the reported Cs levels deserve discussion: the geographical variation, other variations in observed results, the magnitude of the levels observed, the influence of these levels on human exposure, and possible mechanisms and factors influencing these levels. Geographic Variation of Ce8ium-137 Both the grain-fed lean beef and the vegetables show a geographic trend in Cs levels. The highest values occur in the southern and central parts of the State, levels decrease in the northern parts of the State, and they are the lowest in the northwestern part of the State. This is the same general trend as shown by the raw milk levels reported by others. Geographic variations in these three media are compared in Figure 11. 137 Geographical differences in milk and meat 'Cs levels are not so pronounced as in vegetables. The vegetables show much lower levels in the southeastern part of the State, relative to the rest of the State, than do the other two media. Levels in the northeastern part of the State do not drop off as rapidly for milk and meat as for vegetables. The levels in meat from Quincy are higher, relative to the rest of the State, than milk and vegetable levels for the corresponding vicinity. Levels within the latter two media did not differ greatly between this vicinity and the extreme northwestern part of the State. Since dairy and beef animals both receive other feeds in addition to locally grown forage, it can be expected that animal products would 103

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104 20060 o 100 04 Raw Milk I 1

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105 show less pronounced regional variations than vegetables , This may be part of the explanation for the striking difference in the southeastern region between relative levels in vegetables and those in the two animal products . Where regional differences in milk levels are greater than they are 137 in fattened beef, it is probably due to differences in Cs intake by the animals. The intake of dairy cattle will be more characteristic of locality than the diet of feed-lot cattle if the dairy animals are consuming large amounts of local grass or hay, while the fattened beef animals are consuming considerably more grains and supplemental feeds. 137 These latter feeds are likely to have lower levels of Cs than grass and a much wider distribution of origins. 137 With the relatively short effective half-life of Cs in cattle (on the order of 20 days) , feed-lot cattle at slaughter would be essentially in equilibrium with their diet and would show very little reflection of levels of intake from pastures before they were put on the feed lot. Other Variations in Cesium-137 Levels 137 There is a pronounced difference between Cs levels in good to choice meat from feed-lot animals and those in lower quality meat from animals identified as having been fed on various amounts of grass. Although the magnitude of difference is much greater, the direction of the difference is similar to that reported by Ward and Johnson. In 1963, the levels they found in meat from dairy cows and calves on pasture or hay were about three times as high as the levels they found in meat from dairy cows on hay and grain, and in meat from the feed-lot beef animals (Table 18) . At the same time, although unable to completely separate the influence of

PAGE 118

106 i>i a> o n n •* m m 1 I I N o\ m vo o m H H «* tM o H 00 00 es CM c>J o o m ^ CM H I I n m CM O 00 o ON

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107 IX CO vO vO VO CM CO 00 0\ 1^ 00 VO H H I I H I en I I I inC4O\00HevJHi-4 r^ CM CM VO O 00 m in m to vO VO VO vO ov o> o> o% m H H H H VO ON . . • • I-l m Vi »4 M 4J 4J 4J 4J t o o >> cd :b s S B o Szi B 4J 4J ^ .S 43 4:1 4J 4J 4J 4J M 9 9 M 0000 e CO CO ^
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108 IX

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109 age, diet composition, and type of animal, they reported transfer coefficients* from diet to meat that decreased with animal age and that were only about onethird as high for all dairy cows as for beef animals in the feed lot. 137 Ward and Johnson found that Cs levels of forages exceeded those in grain by an order of magnitude. Porter et al . , in investigating the Tampa milk shed, reported levels for pangolagrass hay that were nearly an order of magnitude higher (on a dry weight basis) than other components of the dairy animals' diet and Williams and Nettles reported similar differences between Florida grasses and hays and other components of dairy feed. * Porter shows Tampa pangolagrass ranging from 3,700 to 9,600 pCi/kg in 1963-1964. Ward and Johnson report transfer coefficients of less than 0.01 for dairy animals, about 0.03 for beef animals, and 0.04 to 0.1 for six-month old calves on pasture. ^•'Using an extreme Cs concentration in grass of 10,000 pCi/kg, an extreme transfer coefficient of 0.1, and assuming an intake of 10 kg (dry weight) of grass per day, an equilibrium meat concentration of 10,000 pCi/kg can be predicted. This analysis suggests that either the feed concentration , the transfer from feed to meat , or both , were extremely high in the case of several of the animals sampled . Possible sources of high intake, over and above the grass levels quoted, may have been poor pastures where the animals were forced to browse on close-growing plants in the litter, or where they had access to *Tran8fer coefficient-daily intake of radioactivity/ radioactivity concentration per kilogram of meat.

PAGE 122

no the epiphyte, Spanish moss. Spanish moss (Tillandaia usneodies) was 137 reported by Porter et^ al. to have very high levels of Cs and similar g results have been found in this laboratory. Wykes, studying grassland in the Midwest, reported much higher concentrations of this nuclide in the root mat than in the grass. As an example of the effect of 137 differences in grazing, the presence of Cs levels in moose 3 to 50 times lower than those in caribou from the same area has been attributed to the absence of lichen and possiblie plant litter in the moose diet. No attempt was made here to determine effect of sex, breed, age, or 137 feeding program on the Cs levels of beef from feedlot cattle. In this study, there did not appear to be significant differences in ^^^cs levels between categories of vegetables, but certain crops within various categories seemed to consistently exhibit the highest levels of this nuclide. In contrast to the results of this study, Laug reported great differences between vegetable categories in 1960-1962, with the following ranking, in decreasing order of activity: leafy vegetables, 138 brassicae, root vegetables and fruits, and potatoes (Table 19). He reported lower levels in potatoes than in root vegetables, while in this study, potatoes had consistently higher values than the other root crops. On the other hand, the data of Setter et ^. shows levels in potatoes to 133 be higher than those in lettuce and cabbage. No difference could be shown in this study between the sampling years 1966 and 1967. Because of thesmall number of samples collected in 1966, particularly of beef, a rather large difference must exist before it can be detected.

PAGE 123

Ill vo r» iH sr H r^ in vo H t>. vo H en ir> CM vo en ^^ iv I I I I o o o o o o p*. 00 ON oo en o\ M CM a> 00 •* CM m en 00 o !>• r>.

PAGE 124

112 CO I I o n in vo o i-< en o M o Hi-lvor>.ini-4H>0 "^fT* •* I H I en f». I H I II I o I o I I CM I I »>: o ooi-(r^cn>4-srco>4Hvo en o i-l 00 Oi I tM I »*• CM CM vO H • I • I o 00 *n o> .^nooo o«*«*o OHa>cn r^vDCMr^. H •* ^ c^ H m m OO^rHOONONCMONHCMO cvioo«*T»cMcooo-*a>fioo voorH«nmor^rH»*«* 1-1 H CO H •* H in «>> vo vo 0^ K CO I 8 5 ( .

PAGE 125

113 M 00 00 0\ CO \o m I CM ^ •* o o I en rH i-l I I <0 CO 00 • I • m o I I HrHCOCMrHrHrHH o\tndocooovocsico CM CO CM H rH VO t^ CO •* CM H «*a>oo«neMfOO H •* CI CO r»« CO * * CO Q) 0) ! a o u CM CO •* 60eM CO Sf 60 \o vo vo (d. vo vo NO (d rH H H g H H H gt O O O O O O in lo vo at d . 0) . S •-> n U (0 •H « O O h S to 0)1 > 01 O I T) •ri 9 H CO O 60 «d U •H 6 St VD a\ rH > u HCMCO«*rHeMCOsr V0v0«0v0v0v0v0v0 i-IHrHHrHHtHrH •d 60

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114 IM o o o "n I o 0) o PES !Z! (0 0) CO O 4J 4J O R) U 4J H o cd P4 U n II n is IX pts

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115 Variation with time within the 1967 sampling period was not considered. In Figure 1, it was shown that nationwide radionuclide levels in milk do show seasonal variations that reflect variations in levels in grass , which in turn reflect seasonal variations in deposition. To a certain extent, meat should reflect any fluctuations in diet, because of the short biological half-life of cesitnn in beef. However, there is very little information 137 in the literature from which the degree of seasonal variation in Cs levels in beef or vegetables might be determined. In the Tri-City program, meat showed very little evidence of seasonal variation and there was a gradual decrease during the year of 1965, though levels at San Francisco increased during the last quarter of that year. ' Levels in Chicago vegetables, sampled quarterly since 1961, showed a general tendency to reflect seasonal deposition patterns through 1964. During 1965, when all three stations were sampled quarterly, levels fluctuated so greatly that no seasonal trend was apparent. In contrast, levels of ^'^^Cs in Alaskan caribou and reindeer do show a definite seasonal pattern with maxima in the spring after a winter of grazing lichens, which accumulate the deposited material, and a minimum in the fall after grazing the summer on other plants, which accumulate the nuclide to a lower degree. ' There was no apparent year-to-year trend through 1966 in the caribou and reindeer, primarily because levels in lichens were not changing appreciably. It is entirely possible that the data in this study, all collected in the spring, reflects a seasonal effect and this must be kept in mind when evaluating the magnitude of reported levels.

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116 Magnitude of the Observed Ce8ium-137 Levels It is very difficult to compare values obtained in this study with literature values because the general levels of long-lived radionuclides in the environment have been decreasing the last several years and there is a one to three-year lag before results of radioactivity measurement appear in the literature. Gustafson has extrapolated the radioactivity levels in food categories measured at Chicago beyond 1965 to the end of 1966. These extrapolations were extended into 1967 for the purpose of comparison to the data collected in this study and 1967 values derived from these extended extrapolations are included in Tables 18 and 19. Such extrapolations can be justified on the basis of the following considerations: 1. Fallout deposition peaked in 1964 and has been decreasing since then with a half -life of about two years, 137 2. Plant uptake of Cs is reported to be primarily rate-dependent and accordingly '•^^Cs levels at harvest in both vegetables and animal feeds should be decreasing at approximately the same rate, 3. Cesium has a short biological half-life in cattle, and animal levels follow the levels of feeds; therefore animal levels should also decrease after 1964 with an approximate two-year half-life, and 4. Strontitmi-90 in the total diet has decreased since 1964 with a half-life of about three years and '"^^Cs in the diet should be decreasing even more rapidly since it has less cumulative dependence. Objections to such an extrapolation are the following: 1. Chinese weapons tests since 1964 are contributing some additional 'Cs to the environment.

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117 137 2. The degree of cumulative dependence of Cs may vary from place to place, 3. Some feeds are stored and fed later, making animal levels less directly related to current deposition levels, 4. Gustaf son's extrapolation was performed before the fourth quarter 1965 results were available, and does not take into account that '^^Cs levels in Chicago vegetables increased in the fourth quarter, and 5. In considering a wider sampling basis, meat levels at San Francisco also went up during the fourth quarter, bringing the threecity average up as well. Beef ^^^Cs levels (pCi/kg) appeared to be about two to three times the reported milk concentrations (pCi/1) in the same region of the State. If it is assumed that on the average both beef and dairy animals 137 were receiving comparable levels of Cs intake, this observation is consistent with the ratio of the respective transfer coefficients as 51 reported in the literature. This is also consistent with the relative average levels in the two media as reported for 1965 in the Tri-City diet sampling program. '^" Authors reporting levels of Cs in meat over a number of years all show an approximate doubling from 1962 to 1963. If this doubling factor is applied to Setter's 1962 beef data to correct it to 1963, his results for throughout the United States are comparable to Ward and Johnson's 133 51 1963 results for feed-lot cattle in Colorado. * Differences between species of animals might be expected, especially since feeding habits differ greatly.^* Because of possible species differences, some caution must be exercised in comparing findings to the Tri-City diet data or to Gustaf son's data since the composition of the meat sample is not specified in either of these two.

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118 It can be seen from the data of Bruce and of Hvinden in Table 18, that In the northern hemisphere, beef ^^^Cs levels reached a peak some time 139,140,141 during the period 1963-1964 and have been decreasing since then. Based on these temporal patterns. Ward and Johnson's 1963 data should represent levels just before or very near the maximum, and levels in comparable animals should have decreased to as low or lower levels by 1966 and 1967. The levels reported in this study for Pensacola are comparable to their 1963 feed-lot beef; the results for feed-lot beef from the balance of Florida were one and one-half to three times their 1963 feed-lot data and 0.7 and 0.9 times their values for pasture-fed beef. 137 The most recently published values for * 'Cs concentration in meat in the United States are the 1965 results from the Tri-City program in which levels are reported for meat as a category (exclusive of poultry, 150 fish, shellfish, and eggs) . These data are from market sampling so that the first quarter 1965 maximum probably reflects the later months of the preceding year. It would seem reasonable to expect the spring 1966 levels to be similar to those at the end of 1965, and the spring 1967 levels to be somewhat lower. The overall average for Florida in this study, 214 pCi/kg, is comparable to the 1965 Tri-City average of 217 pCi/kg and the 1965 yearend Tri-City average of 210 pCi/kg. The range of station averages in this study, 105-296 pCi/kg, is comparable to the range of stations averages in the 1965 Tri-City sampling, 170-300 pCi/kg. The range of individual sample results, 55-539 pCl/kg, is wider than the range of individually reported values in the 1965 Tri-City sampling, 33-338 pCi/kg, but this would be expected if individually reported results in the latter program represent composite samples. The Tri-City results for 1965 are higher than the 1967 results for northwestern Florida but are only about two-thirds of the levels found for southern Florida.

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119 The average values found In meat from the Fensacola sampling station are comparable to the extrapolated 1967 value derived from Chicago TriCity program results. Average values for the other stations are all higher than this extrapolated figure, and the average for the Ona station is about three times as high. The fact that levels in grass-fed animals were higher than in feedlot animals is consistent with what was reported by Ward and Johnson. However, the average of these eight samples, 4,000 pCi/kg, is an order of magnitude higher than the average reported by these authors for pasture animals in 1963, and the highest value found is about 36 times as high as their highest reported value. These extreme values are comparable to what has been reported for cattle in Norway and for reindeer and caribou in the artic.^^'^^'^^^'''-^^"-'-^^ The higher values are 137 also comparable to the average level reported by Flummer for Cs in , 131 Georgia deer browsing in the wild. It is even more difficult to compare vegetable results to those 137 reported in the literature than it is for meat because Cs levels reported in literature are so variable. The average levels reported here for most Florida vegetables in 1966-1967 are higher than those reported by Straub for 1958 and by Setter 105,133 for 1962-1963. The regions of the State showing the lowest levels were occasional exceptions to this. For the most part, levels observed in this study were lower than those reported by Laug for the United States during 1960-1962, except for potatoes which had higher levels in 137 the southwest and northeast regions. Statewide levels in this study were generally higher than the 4 Florida averages reported for 1964. Compared to this overall 1964

PAGE 132

120 average, 1966-1967 levels were about the same or lower in the Southeast and Northwest, about the same in the Northeast, and higher in the southwestern and central parts of the State. The Tri-City program samples showed considerable variation among cities and quarters in 1965. However, it would be expected from the trend 150 since 1963 that 1966 and 1967 average levels would be lower than in 1965. Average ^^''cs levels found in Florida vegetables in this study were generally higher than the average of 1965 levels reported for the TriCity program, except for the above-ground vegetables in the southeast, northeast, and northwest regions of the State which had levels equal to or lower than the 1965 Tri-City values. The levels of "^^^Cs in vegetables in the Southeast and the Northwest are comparable to those derived for 1967 from Gustafson's extrapolations of Chicago data, while the levels in the rest of the State are higher than the extrapolated predictions. Since vegetables were selected for this study because ftigh levels of ^^^Cs have been observed in animal forages, it is appropriate to compare the observed vegetable levels to reported forage levels. The forage levels reported for Tampa forage by Porter et al. and Cromroy et al. are reported on the basis of dry weight. ^'^^ In order to put results on a comparable basis, some of the vegetable results from this study, reported on a fresh weight basis, were corrected to a dry weight basis using United States Department of Agriculture values for water content of the various vegetable types. ^^^ The averages for each of the leafy crops collected in the southwest region (the region including Tampa) were corrected to a dry weight basis, the corrected averages weighted for number of samples, and a weighted average for leafy vegetables of 750 pCi/kg was computed.

PAGE 133

121 137 Greens, the leafy crop showing the highest 'Cs levels In that region and probably most comparable In exposed leaf surface to animal forage, have an average •'^''cs content on a dry matter basis of 875 pCl/kg. The individual samples having the highest levels were also corrected to a dry weight basis and these results are tabulated in Table 20. TABLE 20 FLORIDA VEGETABLE SAMPLES WITH HIGHEST CESIUM-137 LEVELS DRY WEIGHT BASIS

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122 animal forage. Some of the difference between vegetables and animal forage can be attributed to the fact that the vegetable samples were all washed before analysis while forage is analyzed on the same basis as it is fed to the animal. Influence of Observed Ce8ium-137 Levels on Human Intake and Exposure The ultimate criterion for evaluation of the significance of observed environmental radiation or radioactivity levels is the effect of these levels on human exposure. The results of the analysis of Florida beef support the conclusion of Ward and Johnson that human intake (and thus body burdens) would be related to the type of beef consumed. ^^ Since the higher levels were in meat from the lower grade carcasses which is made largely into ground beef and processed meats such as bologna and frankfurters, the results also 137 support the suggestion of these authors that Cs body burdens resulting from beef consumption may be related to the economic status of the family. The total radionuclide intake per unit time from all sources, I, may be expressed in terms of individual dietary components (air and water are negligible contributors) in the following manner: I = E w. C^ i where C^ concentration per unit weight of the ith dietary item, and w. » weight of the ith dietary item consumed per unit time. In preparing radionuclide intake evaluation of this data, food categories and estimated average daily intakes for adults in the United States were adapted from the reports of the Tri-City diet sampling program. •'^° Quantity intake values in that program are based on the

PAGE 135

123 United States Department of Agriculture values from the 1955 Household Food Survey. For comparison purposes, two Intake estimations have been derived from published values and are presented In Table 21. The first was obtained by averaging all the 1965 quarterly data reported for the three cities in the Tri-Clty program, and the second from extensions to 150,65 1966-1967 of Gustafson's extrapolations of Chicago data. TABLE 21 CESIUM-137 INTAKE ESTIMATED FROM PUBLISHED VALUES

PAGE 136

124 showing the highest "'^^Cs levels in all media. Intakes due to locally grown foods in the northwestern part of the State should be the lowest in the State, and, since "'•^^Ca levels in that part of the State are essentially the same as expected for the nation on the average, the Northwest average should be similar to national averages. Intakes in regions showing intermediate levels of radioactivity should have correspondingly intermediate values. The amount of locally grown food consumed will vary from famlly-tofamily and probably varies with socio-economic status and with the isolation of the place of residence. For the purpose of this evaluation several hypothetical cases are considered and presented in Table 22. The individual in Case I has cosmopolitan eating habits; milk and dairy products are locally produced, but the other components consist of such commodities as western beef and packaged frozen fruits and vegetables, and are represented by national averages. The "average man" in hypothetical Case II consumes local dairy products, and the higher grades of locally fed meat and receives about half of his fruit and vegetable intake from local sources. The individual in Case III has the greatest local ties, consumes local dairy products, and meats or game with levels corresponding to the average values found for grass-fed animals and receives all his fruits and vegetables from local sources. In Table 21, it was seen that for the nation in 1965, milk, meat, 137 and grain products contributed approximately equally to Cs intake, and fruits and vegetables combined made up less than 20 per cent of the total intake. The Chicago values, extrapolated to 1967, show all levels decreasing with milk and fruits and vegetables decreasing in relative

PAGE 137

125

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126 Importance. By comparison, because of the levels in Florida milk, the major source of "'"^^Cs intake is milk for the Case I Individual. His intake is about 122 per cent of the national estimation for 1965 and about 187 per cent of the Chicago value extrapolated to 1967. For Case II, milk and meat contribute about equally and together contribute about 70 per cent of the intake while fruits and vegetables slightly exceed grain products in contributing to the balance. The total Intake is about two times and three times, respectively, that estimated for 1965 and that extrapolated to 1967. 137 In Case III, meat contributes nearly 90 per cent of the Cs intake and total intake of the nuclide is greater than 10 times the 1965 national estimate and nearly 20 times the projected 1967 estimate. The estimated total intakes all fall below the value of 4,400 pCl/day recommended by the Federal Radiation Council as a guide for the population at large, although the Case II estimate approaches 5 per cent, and the Case III estimate is slightly more than 30 per cent of this value. This guide could be exceeded by groups of people consuming foods, particularly meats, with the extreme values reported. Of the number of methods of estimating body burden and total-body dose rate, the simplest method is to assume an equilibrixim condition in which Intake levels have remained constant for a sufficiently long period of time so that losses from the body are exactly equal to Intake. This approach produces low estimates in times of decreasing Intake levels and high estimates in times of Increasing levels. In this method, when ^^^Cs losses are described by a single exponential function, body burden, Q, may be estimated:

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127 Q = lAi = IA_Zeff = 1.44 I A T.ff X 0.693 where I = Intake as previously defined, A = fraction of intake absorbed, \ = elimination constant, and Tgff = the effective half -life, 0.693/X . For •''^Cs, the physical half-life is so much longer than the biological half-life that the effective half-life may be taken as equal to the biological half-life and absorption is nearly 100 per cent, so that: Q = 1.44 I T^. For an assumed value of T^^ = 100 days: Q = 144 I. Body burdens predicted in this manner are shown in Table 23 along with values from the literature. It can be seen that the body burden for Case I is slightly more than estimated for the entire United States in 1965 and measured in Chicago residents at the beginning of the year, and it is about twice that estimated from the projected intake for 1967. The Case II value, directly reflecting a higher estimate of radionuclide intake, is about 50 per cent higher. The Case III value is greater by an amount proportional to the higher estimaced intake and la comparable to those measured during April-May, 1966,. in Alaskan men eating caribou or reindeer several times a week. The estimated body burdens, even in Case III, are below the Federal Radiation Council's Radiation Protection Guide of 3,000 nanocuries (nCi) for whole body exposure of Individuals in large population groups (1,000 nCi when estimation is made for a suitable sample 62 of the group rather than measuring individuals) .

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128 a « o o o o o o o o r^ o\ m o
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129 Dose rate may be computed for the equilibrium case: w where R = dose rate, rads/year, Q " body burden, (yCi) as previously derived, W = body weight, kg, and 11 = a conversion factor, kg-rads/pCi-year, when the average energy absorption in the body is assumed to be 0.59 MeV/disintegratlon . The expression for intake may be incorporated: R = 11 1 X 1.44 T, W ^ or, in the case of the 70 kg standard man and T^ = 100 days, R = 22.6 I. 137 For Cases I, II, and III, the dose rate from •^""Cs computed in this fashion would be 3.25, 5.3, and 32 millirads/year, respectively. These contributions to the total dose rate may be compared to the Radiation Protection Guide of 500 mrem in a year to the whole body of individuals in the general population or an average of 170 mrem when measuring a 62 suitable sample of the group rather than individuals. Because of the uncertainties from region-to-region, family-tofamily, and person-to-peraon in dietary habits, food preferences, and quantities of intake, the differences between adults and children, and the generalized nature of many of the assumptions made, the estimates of '•^^Cs intake, body burdens, and dose rate in this chapter can only be considered as crude indications
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130 Possible Mechanisms and Factors Influencing Ceslum-137 Levels In Florida No evidence can be found to Indicate that the ^^^Cs currently found In the Florida environment has any source other than past or current fallout deposition from nuclear testing, 137 According to the literature, environmental levels of 'Cs are generally Independent of total accumulated deposition because this nuclide Is bound so tenaciously to the soil. It is recognized that uptake can be related to a certain extent to accumulated deposition over the Immediately preceding one or two years because Cs can remain available In the root mat and In organic material for a time after deposition. However, uptake Is usually considered to be primarily due to direct deposition and thus the levels are considered to be primarily related to the current rate of deposition. According to the generalized theory of latitudinal dietribution of fallout deposition, Florida should lie considerably south of the northern hemisphere maximum (approximately 40°) and in a region of rapidly 34 37 diminishing levels from north to south. * Strontlum-90 levels in soil samples collected from sites throughout the country. Including one each in North and South Florida, support this theory. This generalized pattern is modified by local factors. Maritime exposure has been raised and then discounted as one of the possible modifying factors. *^^^ Precipitation is generally believed to be a significant local modifier of distribution patterns, with high precipitation areas having increased deposition rates and accumulated deposition. If radioactivity levels are highly rate dependent, amount of rainfall during the particular

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131 growing season of the vegetation fed or sampled could be highly significant. In addition. Ward and Johnson report immediate response in 137 vegetation and milk to variations in amount of Cs deposited by precipitation.*^ »^^^ No direct studies have been performed yet in Florida to determine the effect of either average rainfall, growing season rainfall, or individual rains on environmental ^^^Cs levels. Examination of the mean annual precipitation contours in Florida for the period 1931-1955 shows that the highest annual rainfall, greater than 56 inches, occurs in much of what was designated in this study as the southeast and northwest regions. '^® Most of what were designated as southwest, central, and northeast regions lie below the 56 inch contours. Exceptions to this general pattern are a small region of about 56 inches and greater north of Tampa (Brooksville area) and a sharp gradation from 56 inches to 48 Inches and less south and east of Miami and Homestead. It appears that the 1966-1967 levels of ''•^^Cs in Florida vegetables show an inverse relationship to the average annual precipitation. Only limited significance can be placed on the above observation, however, because precipitation can be highly localized and can vary considerably from year-to-year. No consideration was given to actual precipitation at the particular growing site during the whole growing period for the particular samples collected or during the period immediately preceding sampling. Examination of local rainfall records for late 1966 and early 1967, as they become available, should be particularly Interesting. Studies of "^Cs in vegetables in 1960-1963 showed considerably more radioactivity in leafy vegetables than in other types, but no

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132 such difference could be demonstrated in this study. This might be due to surface contamination being more thoroughly washed off in sample preparation. On the other hand, the leaf activity found in earlier studies could have been due to insoluble contamination from foliar deposition tightly retained on the surface of the leaf and foliar deposition absorbed by the leaf, but not effectively translocated throughout the plant. If it is assumed that ''•^^Cs deposited in 1966-1967 would be no more soluble than that deposited earlier, the absence of selectively high levels in leaf crops in 1966-1967 suggests that in these later years, ^-^^Cs is being distributed throughout the plant and thus must have come from some source other than foliar deposition. Coupled with the soil uptake by grasses demonstrated by Cromroy et al. , this is strong evidence for the role of a ctmulative dependent mechanism and uptake from the soil in Florida ''•^^Cs levels. 137 Unusual environmental factors must be involved in the Cs levels found in Florida, although it has not been determined whether these 137 involve unusual deposition, unusual uptake by biota from available Cs, 137 or unusual availability of the accimiulated deposit. Rates of Cs deposition in various parts of the State have not been evaluated, but it does not seem likely that deposition can account for the variations and levels seen. Neither does it seem likely that an unusual uptake would be an inherent characteristic of all of the wide variety of plant species in which unusual levels of this nuclide have been noted. This leaves, as the most likely explanation, some unusual environmental factor or 137 mechanism accentuating the uptake from currently deposited Cs or making the accumulative deposit in the soil more available for uptake. Climatic factors, physiographic features, cultivation practices, and

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133 soil practices are some of the factors which might play a role in unusual •^^^Cs uptake. The existence of factors resulting in unusual biospheric accumulation of ^^^Cs has important implications in waste disposal, operation of nuclear facilities, and hazard evaluation, and this situation still deserves considerable exploration. Other Radionuclides _ 137 The primary emphasis in this study was on Cs and only limited attention was given to analysis and interpretation of other nuclide results. The presence of radium daughter activity in such a large proportion of the samples analyzed suggests that radium may be a significant source of environmental radiation exposure. Except for measurements of radon daughters in air and gross alpl^a activity in a variety of other media, radium and its daughters have not been studied to any extent in Florida. Nuclide activities, in addition to '•^^Cs, ^ K, and radium, which occurred in a sufficient number of samples to merit consideration were primarily fresh fission products. The fresh fission-product activity in the May 21-26, 1966, samples indicated that Florida received deposition from the Chinese atmospheric nuclear detonation of May 9, 1966. This is consistent with the report of Grundy and Snavely which shows an intrusion over Florida of the fresh fission-product debris cloud about 166 May 17-19, 1966. The fresh fission-product activity in January and February of 1967 can be attributed to the Chinese atmospheric nuclear test of December 28, 1966.199

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134 The activity found in vegetables at this time appeared to be surface contamination due entirely to direct deposition on exposed leafy surfaces. The activity appeared only in the very leafy vegetableslettuce and greens. Very little activity was found in the celery samples which consistented mainly of stalks after about one-half of the leafy top was removed in sample preparation. No activity was detected in cabbage from which the outer leaves were discarded before analysis. The activity disappeared from the vegetables at a more rapid rate than would be indicated by the half-lives of some of the nuclides and it never appeared in other than leafy samples. It appears that very little of these nuclides was absorbed from the surface contamination and translocated. This distribution pattern is in contrast to those exhibited by ^•'''cs and ^^^Ra and daughters, nuclides which appeared in all vegetable types and appeared to have been widely translocated in the plant. The statewide occurrence of these fresh fission-products is also in contrast to the occurrence of ^^'Cs which had a definite geographic pattern. Discussion of Sources of Error Most computational procedures for resolving complex gamma spectra into individual components, including the simultaneous equations method used here, require an a priori assumption of the composition of the mixture. This results in two inherent weaknesses. If a nuclide is present that is not in the calibration matrix, an error can result. The magnitude of this error for the various nuclides reported depends upon the particular spectrum and the amount present of the omitted nuclide. The second weakness is related to the effect of including nuclides in the calibration mixture which are not in the sample spectrum. This

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135 results In aa increase In the standard deviation of the level reported for each of the nuclides which are present. During the time that this study was carried out, several nuclear weapons tests were conducted in the atmosphere, resulting in the transient appearance of short-lived nuclides in the enviromnent . The very shortlived nuclides (half -lives less than seven days) were not included in the calibration matrix. However, this should not have introduced a serious error since all of the 1966 and most of the 1967 samples were counted a sufficiently long time after the arrival of fresh fallout to eliminate or at least greatly reduce the contribution of these components. It should be noted that the cerium calibrations were made with an equilibrium mixture of "'^^Ce/Pr (half-life of 285 days) and ruthenium calibrations with one of ''•^^Ru/Rh (1.0 years). The presence of Ce (32.5 days) and ruthenium-103 (40.0 days), with a gamma spectra similar but not identical to those of their respective long-lived fission product isotopes, probably contributed some error to the results reported for samples contaminated with recent fallout. Although ^^Zn has been^eported in foodstuffs in the past, it was not included in the calibration matrix and the unrecognized presence of this nuclide may have been another source of error. Only limited significance can be placed on the reported quantitative values for ^^^Ra and its daughters. They were not necessarily in equilibrium, mainly because no effort was made to prevent the loss of the gaseous intermediate, radon-22 (^^^Rn) . This nuclide chain was included in the calibration matrix primarily to correct for interferences with 137 other nuclides, notably interference with the 0.66 Mev Cs peak by the 0.61 MeV bismuth-214 (^"'Si) peak and with the 0.36 Mev I peak by the

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136 0.35 MeV lead-21A ( Pb) peak. For the estimation of radium daughters, the 1.12 MeV Bl peak was selected as being the most abundant peak not directly interf erring with another major photopeak. Nevertheless, the low abundance of this peak relative to the other two peaks just mentioned, ^ 137 ^ 131 contributes to the uncertainty in the estimation of Cs and I. In addition, the xmrecognized presence of Zn (1.11 MeV) which was not included in the calibration matrix, would result in overestlmation of radium daughter Interferences. Although ce8lum-134 ('"^^Cs) <0.60 and. 0.80 MeV) has been. reported to be present in environmental samples to the extent of 1.0 to 1,5 per 137 cent of the Cs, it was not Included in the calibration matrix. This may have introduced some errors, particularly in the reporting of, and 54 correction for interference from, Mn (0.84 MeV). However, because of 134 the half-life of only two years, Cs levels should have been well 137 below 1 per cent of the Cs levels at the time the samples in this study were analyzed. Any positron emitters present in the sample would have produced a 0.51 MeV peak in the spectra which would have been interpreted as '^^Ru/Rh, thus resulting in overestlmation of Ru/Bh and consequently 137 in underestimation of Cs because of over-correction for interference of the 0.61 MeV Ru/Rh peak. Other nuclides not included in the calibration matrix were not believed to be present in sufficient quantities to seriously affect the accuracy of the results reported. The analysis of the geographic variation of levels in lean beef might be criticized on the; grounds that while the samples from the four eastern-most stations were all the same cut of meat and collected from experiment stations animals, the samples at Station 5 were unidentified

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137 cuts from animals on undocumented feeding programs. With regard to the cut of meat, other investigators have reported that variance due to the particular muscle sampled is not significant relative to the anlmal-to51 animal variation and variation Introduced by counting statistics. With regard to the feeding program, it is possible that some or all of the animals from Station 5 were finished on diets that contained a higher pasture to grain ratio than contained in the experiment station diets . However, at a different station in this study, increasing the forage to 137 grain ratio in the animals' diet markedly increased the Cs content of the meat. 137 The influence of Cs contribution to the environment by Chinese weapons testing since 1964 was not considered in extrapolating literature values to 1966-1967 for comparison to the values obtained in this study. It was assumed that this contribution was not significant in relation to the other uncertainties in such an extrapolation. Further Investigations Suggested by the Results of This Work The results of this study suggest further work in at least four 137 areas, (1) assessment of human exposure to Cs, (2) study of environmental factors contributing to ^^^Cs levels, (3) studies of natural radioactivity in Florida, and (4) derivation of parameters for conducting monitoring and surveys. Assessment of hxman exposure Further investigation of Florida meat and meat products is indicated. Such work should be accompanied by a determination of the origin and quantities produced and consumed of various meat grades and meat products, information probably available from published literature. Further surveys are needed of levels of ^^^Cs in products sold over the counter.

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138 particularly ground beef and processed meats such as frankfurters and bologna, to determine the extent to which the higher levels observed in the lower quality carcasses are reflected in these products. Corollary work would be the investigation, on a wider basis, of the relative levels of '^^Cs in feed-lot and range cattle in Florida. In view of some of the predictions of this study, a second Indicated area of human exposure assessment is the investigation of htman body burdens of "'"'''cs— both the variation within the State and a comparison with other reported values. Data could be obtained from three sources — other installations that have counted Florida persons, retrieval of ^^^Cs content from whole-body counts already performed at the University of Florida, and a deliberate study of ^^''cs levels in Florida individuals. Several commodities neglected in this study also deserve further 137 consideration. Slnce_ fresh water fish have been shown to have high Cs levels in other parts of the country and according to Guatafson these levels can significantly affect Intake of this nuclide by individuals of groups substituting fish for a considerable portion of the meat in the 54,55 standard diet, this medium deserves further study in Florida. Citrus was not Included in this study but it deserves further consideration because it is a very economically Important crop in Florida. As pointed out by several authors, there is also a need for further work in developing methods of predicting human exposure on the basis of environmental measurements. ' It appears that levels of Cs are sufficiently high in certain segments of the Florida environment to make such studies under natural conditions more feasible here than in many other parts of the country.

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139 Environmental mechanlama Although various Investigators have studied the Florida environments, 137 the particular environmental factors responsible for the observed Cs levels still have not been Identified. It still Is necessary to determine what portion of the observed levels can be attributed to deposition rate and what portion to accumulated deposition. If accumulated deposition makes a significant contribution, the environmental mechanisms making the Florida situation so unique should be described. 137 One question is the magnitude and distribution of Cs deposition in Florida. This might be evaluated by examining past and current data of the USAEC and Florida State Board of Health sampling stations and perhaps by conducting prospective deposition sampling at one or more locations. As an alternative, distribution might be estimated from surface air concentrations since air sampling continues at the various stations of the Florida Radiation Surveillance Network and filters are available from the past several years. Another aspect of •'•^^Cs deposition is the question of whether or not '^^Cs/^^Sr ratios have been constant in deposition or whether they have varied geographically as they do in milk. Information might be retrieved from past and future data from the USAEC deposition sampling program and deposition sampling of the Florida Radiation Surveillance Network aupnented by additional or modified stations if necessary. Alternatively, the ratios might be estimated from surface air samples or from deposition as estimated by statewide Spanish moss sampling. Precipitation residues from 1955-1966 and air sampling filters from the Florida Radiation Surveillance Network have been turned over to the University of Florida and a number of statewide Spanish moss samples collected during 1966 are being held on hand.

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140 The relative importance of rate dependence and cvimulative dependence might be explored by fitting models to existing data, particularly the milk data that has been collected monthly for a ninnber of years. It might also 137 90 be explored by examining the behavior of the Cs/ Sr ratio with time and with changes in the deposition rate, thus determining whether the two nuclides have proportional or different dependence on deposition rate. The work of Cromroy et e^, strongly suggests that uptake from the 137 soil may be an important factor in •^""Cs levels in Florida vegetation, and this is a promising area for further investigation. Florida soils, particularly from areas where high vegetable radioactivity levels were observed, can be identified either by soil type or geographic location and 137 submitted to three tests, total Cs content (indicative of accumulative 137 deposition), "exchangeable" or "available" Cs content and exchange and 137 fixing capacities. The available Cs content and capacity might be measured by either "test tube" or "greenhouse" methods or both. The influence of modifying factors such as soil pH and soil moisture content might be examined at the same time. Since general location of the source is available for all samples analyzed in this study and specific farm or field can be determined for many of them, further investigation also might be made of factors relating to the levels observed in specific samples. These factors might include rainfall during the entire growing season preceding sampling, rainfall in the period iimnediately preceding sampling, average rainfall for the area, soil type, soil pH, and fertilizing and other farming practices. Finally, a controlled study might be performed to evaluate radionuclide balances and rates of transfer, and ultimate transfer to meat in feed lot and pasture situations.

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141 Studies of natural radioactiv ity In Florida The presence of ^-"-^Bl and ^^Sb In so many of the gamma spectra for samples In this study and other environmental radioactivity studies currently being performed at the University of Florida suggests that higher than average levels of natural radioactivity are appearing In Florida environmental media. The vegetable and beef samples currently on hand might be analyzed for radium and other natural radioactivities and the results compared to available data to determine the Importance of further natural radioactivity studies. If further study appears justified, the Influence of calcium levels in Florida soils and agricultural liming practices might be important factors to explore. Parameters for conducting monitorin g and surveys As the number of radioactivity handling or producing Installations in the southeastern states grows, surveys and monitoring programs will be carried out to determine preoperational radioactivity levels and to determine influence of the operations on the environment. In addition, surveys will continue to be made to assess overall radiation exposure levels. This study has shown that wide variation is present in at least one nuclide in the Florida environment and has suggested that the frequency distribution of these levels is not normal. From the data already collected it is possible to identify Important sources of variance, to derive estimates of variance for particular populations, to estimate sample sizes needed to make certain decisions and to optimize the distribution of effort between replicate samples, replicate analyses per sample and minutes of counting time per analysis. Hawthorne has reported high variability in the levels of radionuclides in various components of an agricultural system and he pointed out that in order to

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142 develop a model to describe such a system, these variations must be taken into account and the model must be constructed from actual observations upon the system over some period of time rather than from assumptions. ( '

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CHAPTER VIII SUMMARY AND CONCLUSIONS This research involved a study of the kinds, levels, and distribution of gamma-emitting radionuclides in the Florida environment and the evaluation of these levels in terms of human exposure. In sampling and analysis, 137 emphasis was placed on Cs in beef and vegetables . Preliminary sampling was carried out in May and June, 1966, and full scale sampling was conducted during January through Juiy, 1967. Analyses were performed by gamma spectroscopy on triturated samples without ashing and without chemical preparation or separation. Complex gamma spectra were interpreted in terms of the individual contributing components by use of the simultaneous equations method. 137 Levels of Cs in both beef and vegetables showed geographical patterns similar to -those reported earlier by others in Florida milk. Maximum levels were found in the central and southern parts of the State, with diminishing levels occurring in the northeastern part of the State and the very lowest levels occurring in the northwestern part of the State. The animal products did not show variations as great from regionto-region as did the vegetables, probably due to the averaging effect of movement of feed from region-to-region and into the State from outside. Vegetable levels differed from beef and milk, in that the levels found in the southeastern part of the State were as low as in the northwestern part while average beef and milk levels in this vicinity were only slightly less than seen in the central and southwestern parts. Meat 143

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144 levels did not decrease as rapidly from east to west in the northern part of the State as did milk and vegetable levels. In contrast to the results of earlier work by others who sampled throughout the United States, there was no apparent difference in ^^^Cs concentrations between leafy, fruit, and root categories of vegetables. Certain crops in each category did exhibit consistently higher levels than other crops in the same category. It was not possible, with the ntimber of samples collected, to demonstrate any clear-cut difference between the 1966 and 1967 sampling years for either beef or vegetables. Possible seasonal effects during the sampling period were not taken into consideration. It was difficult to find radioactivity concentration values in the literature against which to compare values found in this study. There is a twoto three-year lag time in publishing data and though radioactivity levels in most environmental media have been decreasing since 1963 or 1964, they have varied so much with time and location that extrapolation is difficult. The statewide average of Cs levels in fattened beef was 214 picocuries per kilogram (pCi/kg) , and the range of individual samples was 55-539 pCi/kg. This average is comparable to average national levels reported for beef in 1965. Levels in samples from the western part of the State averaged 105 pCi/.kg and ranged from 55 to 174 pCi/kg. This average is comparable to 1964-1965 Chicago meat-values extrapolated to 1966-1967. The levels in samples from the stations in the balance of the State were two to three times this extrapolated value. Levels of ^^^Cs in a group of samples representing lower qxxality meat from animals which presumably had fed on grass averaged about

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145 4,000 pCi/kg and ranged from about 300 to over 12,000 pCl/kg. These values are much higher than those in high quality meat from feed-lot animals from the same general vicinity and are higher than any other reported beef levels in the country. The highest values approach levels reported for reindeer and caribou in the arctic. Cesium-137 levels in vegetables from southeastern and northwestern parts of the State averaged about 25 pCi/kg and ranged from below detectable limits to 176 pCi/kg. This average level is comparable to national values extrapolated to 1967, but averages from several regions were considerably higher. The average levels in the northeastern part of the State were about 50 pCi/kg with a range from below detectable limits to about 200 pCi/kg, and those in the central and southwestern parts were on the order of 90-100 pCi/kg with a range from below detectable limits to 560 pCi/kg. Average vegetable levels, expressed on a dry weight basis, were lower than values reported in recent years by others for pangola hay in Florida, but maximum vegetable values were higher than the highest values reported for hay. Cesium-137 intakes were estimated for three hypothetical cases of assumed diet composition and source of food. It was estimated that radioactivity intakes from locally produced food in Northwestern Florida would be similar to the national average. On the other hand, in the remainder of the State, Florida milk alone would double the intake of 137cs and thus the body burden of this nuclide under long-term exposure conditions. It was estimated that if locally grown fattened beef was substituted for other meats in the diet in the central and southwestern parts of the State, radioactivity intake and body burdens would rise to

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146 three times the eatimated national average. When it was assumed, for the same part of the State, that meat In the diet was at the average level found for grass-fed beef and that all fruits and vegetables 137 , consumed were at the average levels found for vegetables, Cs intake and equilibrium body burdens were estimated to be about 20 times the projected national average. The intakes, body burdens, and resulting whole-body radiation doses estimated for each of these cases were less than the respective radiation protection guides, but the guides could be approached by individuals consistently consuming food at the extreme levels found. 137 The mechanisms responsible for the unusual patterns of Cs levels in Florida were not identified but there is increasing evidence that, 137 contrary to what is usually stated for Cs, uptake from the soil plays a significant role. A number of further studies appear to be indicated, particularly of the levels in, and possible radionuclide intakes due to, processed meat products made from the lower grades of meat, of the factors involved in ^^^Cs levels in meat from grass-fed beef in Florida, of •'^'Cs body burdens of persons living in Florida and the relationships of these burdens to eating habits and food sources, and of the role of soil as a 137 source of biospherlc Cs in Florida. Conclusions 137 1. The relatively high levels of Cs reported for Florida milk are also reflected in other environmental media. 2. The geographical patterns of variation of -^-"Cs levels seen within the State for milk are also seen (with certain modifications) for beef and vegetables, with highest levels in the central and southwestern parts of Florida.

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147 3. Levels of ^^^Cs in beef from grass-fed animals in Florida can be much higher than those in grain-fed animals. 4. Although varying considerably with dietary habits, intake of •••^^Cs by humans and corresponding body burdens in a considerable portion of Florida should be significantly higher, on the average, than those for the nation as a whole. 5. Average body burdens of •''^^Cs for groups of central Florida residents can be expected to range between 20 and 200 nCi, depending on type and source of food. 6. None of the average intakes, body burdens, or resulting totalbody radiation doses estimated from "^^^Cs levels observed in this study exceed the applicable radiation protection guides. 137 7. The elevated levels of Cs in the central and southern parts _ of Florida appear to be due to unusual environmental factors or mechanisms influencing the uptake by vegetation from current deposition of or accumulative deposits of this nuclide. These factors and mechanisms can have important implications with regard to waste disposal, site and hazard evaluation, and operation of nuclear facilities. 8. There is increasing evidence for the importance of uptake from 137 the soil as one of the factors in the Cs levels observed in Florida. 9. A number of further studies are indicated, particularly of Cs 137 in Florida meat products, of human body burdens of Cs in Florida, and of the soil and other factors Involved in the observed levels and patterns.

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APPENDICES

PAGE 161

APPENDIX A EQUIPMENT AND INSTRUMENTATION

PAGE 162

tt) H m a P o o H 00 t I a o t4 u CO M 3 bO •a •;3 n rr •H H W H •g^ ' d u 0) 43 •« 4J u a o •H H O • >?'$ sr o q. ^5 m 0) •sa O •H "H m «* "I O C4 01 §1 iH cd IW u o'O tiO n 01 la 0) -d •rj •a a o o ^ u u a •H TJ "d 3 u PM 0) H P O M-< •H O 4J.il! Id M WHO « O tH 'd o 0) O O B "^ 8 «« bO-H a III & 0) 4J 10 •> u m 0) (0 0) 4J -H < O T 3 H 0« 0) 01 m 1^ c>i o VO VO 00 CO VO NO

PAGE 163

151 4J o a DO u a «d • ^ <« H HMO 0) O > m -H MH ^ -•H 00 H t-t -H § S M Id O ,d M 4J t>% U Id U H (U h 4J u 0) U ii 0) tI 4i ^M M O 0) P< Xi (d •d at I g u (0 Id 0) u •H • M « ^ O (Q U P (0 o Fm •H § iJ CO 15 CO o 3 a H O td a a H 4J n (d 0) SI i-B t»»H 01 (d rH O 0) to * •^ 3 • -o iJ Id m • Id (0 o I

PAGE 164

APPENDIX B GAMMA-EMITTING RADIONUCLIDES INCLUDED IN THE CALIBRATION MATRIX

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<]•

PAGE 166

LIST OF REFERENCES 1. United States Public Health Service, "Pasteurized Milk Network," Radiological Health Data (and Reports) . Vol. 1-8 (1959-1967). 2. Division of Radiological and Occupational Health, Florida State Board of Health, Report of Florida Radiological Data Environmental Monitoring Programs 1962 . Jacksonville, Florida (1964). 3. Division of Radiological and Occupational Health, Florida State Board of Health, Report of Florida Radiological Data Environmental Monitoring Programs 1963 . Jacksonville, Florida (1964). 4. Division of Radiological and Occupational Health, Florida State Board of Health, Report of Florida Radiological Data Environmental Monitoring Programs 1964 . Jacksonville, Florida (1965). 5. Division of Radiological and Occupational Health, Florida State Board of Health. Report of .Florida Radiological Data Environmental Monitoring Programs 1965 . Jacksonville, Florida (1966). 6. Division of Radiological and Occupational Health, Florida State Board of Health, "Florida Milk Network." Radiolofeical Health Data (and Reports) . Vol. 5-7 (1964-1966). 7. Williams, E. 6., E. Nettles, Florida State Board of Health, Personal Communication. 8. Porter, C. R. at al . , "The Cause of Relatively High Cesium-137 in Tampa, Florida, Milk," Radioecological Concentration Processes . Pergamon Press, Oxford (1966). 9. Roessler, C. E. and E. G. Williams, "Radionuclides in Florida Milk," Public Health Service Research Grant, unpublished. 10. Hoard, Allen G. , M. Eisenbud, J. H. Harley, Annotated Bibliography on Fallout Resulting from Nuclear Explosions . NYO-4753 (1956). 11. Congress of the United States, Joint Committee on Atomic Energy, The Nature of Radioactive Fallout and Its Effects on Man . Hearings Before Special Subcommittee on RAdlation (1957). 12. Congress of the United States, Joint Committee on Atomic Energy, Fallout from Nuclear Weaponfl Tfests . Hearings Before Special Subcommittee on Radiation (1959) . 13. Caldecott, Richard and Leon A. Snyder, editors. Radioisotopes in the Biosphere . Proceedings of Symposium, University of Minnesota, Minneapolis, Minnesota (1960). 154

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155 14. Schultz, Vincent and Alfred W. Klement, Jr., editors. RadloeCiblbgv. Proceedings of the First National Symposium on Radioecblogy, Colorado State University, Fort Collins, Colorado, 1961, Reinhold Publishing Co., New York (1963). 15. Klement, Alfred W. , Jr., editor, Radioactive Fallout from Nuclear Weapons Tests . Proceedings of a Conference, Germantown, Maryland, 1961, TID-7632:1 and 2 (1962). 16. Klement, Alfred W. , Jr., editor. Radioactive Fallout from Nuclear Weapons Tests . Proceedings of 2nd Conference, Germantown, Maryland, 1964, CONF-765 (1965). 17. Eisenbud, Merril, Environmental Radioactivity . McGraw-Hill Book Co., Inc., New York (1963). 18. Fowler, Eric B., editor. Radioactive Fallout . Soils . Plants . Foods, Man, Elsevier Publishing Co., Amsterdam (1965). 19. Adams, John A. S. and Wayne M. Lowder, editors. The Natural Radiation Environment . Proceedings of the First International Symposium on the Natural Radiation Environment, Houston, Texas, University of Chicago Press (1964). 20. Klement, Alfred W. , Jr., Natural Environmental Radioactivity . WASH1061, Washington, D. C. (1965). 21. Hungate, F. P., editor, "Hanford Symposium on Radiation and Terrestrial Ecosystems." Health Physics . 11:1255-1676 (1965). 22. "The 2nd National Symposium on Radioecology," Ann Arbor, Michigan, 1967, to be published. 23. Comar, C. L., "Movement of Fallout Radionuclides Through the Biosphere and Man." Ann. Review of Nuc. Sci. . 15:175-206 (1965). 24. Ellis, R. E. , "An Appraisal of the Current Fallout Levels and their Biological Significance," review article, Phvs. Med. Biol. . 10:153-76 (1965). 25. Llden, Kurt and Erik Lindgren, editors, "The Present Fallout Pattern in the Nordic Countries, Radioactive Waste," Proceedings of the First Nordic Radiation Protection Conference, Stockholm, Sweden, Acta Radiol. . Suppl. 254:158 (1966). 26. Leiatner, Lothar, Research on the Radioactive Contamination of Foods of Animal Origin . CEA-R2738 . (French), translated by C. E. Roessler, University of Florida (1965) . 27. Russell. R. Scott, editor. Radioactivity and Human Diet . Pergamon Press, Oxford (1966).

PAGE 168

156 28. United States Department of Health, Education, and Welfare, United States Public Health Service. RAdloloelcal Health Data (and Reports) , Vol. 1-8 (1960-1967). 29. Williams, E. 6., J. C. Golden, Jr. , C. E. Roessler, U. Clark, Study of Natural Background Radiatloii in Florida . Florida State Board of Health, Jacksonville, Florida (1965). 30. "Environmental Levels of Radioactivity at Atomic Energy Commission Installation's Pinellas Peninsula Plant." Radloloftical Health Data (and Reports) , Vol. 2-8 (1960-1967). 31. Florida Nuclear and Space Commission, Tallahassee, Florida, Personal Communication. 32. Langham, W. H., Radioactive Fallout . Soils . Plants . Foods, Man, American Elsevier Publishing Co., Inc., New York, 3-18 (1965). 33. Langham, W. H. and E. C. Anderson, "Cesium-137 Biospheric Contamination from Nuclear Weapons Tests," Health Physics . 2:30-48 (1959). 34. Davis, J. J., "Cesium and Its Relationship to Potassium in Ecology," Radioecology . Relnhold Publishing Co., New York, 539-556 (1963). 35. Russell, R. Scott, "Interception and Retention of Airborne Material on Plants . " Health Physics . 11:1305-15 (1965). 36. Klement, Alfred W. , Jr., "Radioactive Fallout Phenomena and Mechanisms," Health Physics . 11:1265-74 (1965). 37. List, Robert J. et al., "Strontlum-90 on the Earth's Surface, III," Radioactive Fallout from Nuclear Tests . CONF-765:359 (1965). 38. Machta, Lester, "Status of Global Radioactive Fallout Predictions," Radioactive Fallout from Nuclear Tests , CONF-765 : 369 (1965) . 39. Federal Radiation Council, Estimates and Evaluation of Fallout in the United States from Nuclear Weapons Testing Conducted Through 1962 . Report No. 4, Washington, D. C. (1963). 40. Federal Radiation Council, Rfevised Fallout Estimates for 1964-1965 and Verification of the 1963 PredifctiOns . Report No. 6, Washington, D. C. (1964) . 41. Pelletier, C. A., G. Hoyt Whipple, Harold L. Wedllck, "Use q£ Surface Air Concentration and Rainfall Measurements to Predict Deposi^l^n of Fallout Radionuclides," Radioactive Fallout from Nuclear Teats . CONF-765: 723 (1965). 42. Pendleton, R. C, , "Accumulation of Ce8lum-137 Through the Aquatic Food Web," Biological Problems in Water Pollution . Public Health Service Publication No. 999-WP-25, 355-3 (1965).

PAGE 169

157 43. Schulz, R. K. , "Soil Chemistry of Radionuclides ," Health Phyaica , 11:1317-24 (1965). 44. Menzel, R. G., "Soil-Plant Relationships of Radioactive Elements," Health Ph^dica, 11:1325-32 (1965). 45. "Summary of Research Results Related to Environmental Radioactivity," Radiological Health Data . 1:30-1 (1960). 46. Pendleton, R. C, University of Utah, Salt Lake City, Utah, Personal Communication . 47. Wykes, E.R., "Cesium and Strontlum-90 In a Dairy land Environment," Radiological Health Data and Reports . 7:545-7 (1966). 48. Johnson, J. E. and G. M. Ward, "Ceslum-137 In Milk from Dry-lot and Pasture-fed Cows In Fort Collins, Colorado, during 1963," Radiologic^ Health Data . 6:29-30 (1965). 49. Elder, Robert L., Wellington Moore, Jr., "Comparison of Ceslum-137 Bdndlng Characteristics In Pangola Hay and Spanish Moss," Radiological Health Data . 6:586-9 (1965). 50. Pendleton, R. C. e£^. , "A Trophic Level Effect on Ceaium-137 Concentration," Health Phislcs, 11:1503 (1965). 51. Ward, G. M. and J. E. Johnson, "The Ce8ium-137 Content of Beef from Dairy and Feed-lot Cattle." Health Physics, 11:95-100 (1965). 52. Kreuzer, W. , "Influence of Management and Feeding on the Contamination ^^ of the Flesh of Cattle with Ceslum-137 and Methods for its Measurement, Zentralbl. Veterlnaermed. . 12:592-9 (1965). 53. Kahn, B. et ^. , "The Relation Between the Amount of Ceslum-137 in Cows' Feed and Milk," J. Dairy Scl. . 48:556-62 (1965). 54. Guatafson, P. F., "Ceslum-137 in Freshwater Fish: Consumption and Body Burden Considerations," Radiological Health Data, 6:626-30 (1965). 55. Gustafson, P. F. et al . , "Caeslum-137 in Edible Freshwater Fiah," Nature . 211:843-4 (1966). 56. Richmond, C. R., J. E. Furchner, W, H. Langham, "Long-Term Retention of Radiocealum by Man." Health PhyalCB, 8:201-5 (1962). 57. Hardy, Edward P., J. Rivera, Robert Conard, "Cesium-137 and Strontlum90 Retention Following an Acute Ingestion of Rongelap Food," Radi6active Fallout from Nucilear Weapons Tests, CONF-765:743 (1965). 58. McGraw, T. G. , "The Half-Tlme of Ceslum-137 in Man." Radloloftical Health Data. 6:711-8 (1965).

PAGE 170

158 59. Eberhardt, L. L,, ^'Relationship of Ceslum-137 Half -Life In Humana to Body Weight." Health Phvaics , 13:88-90 (1967). 60. "Report of International CommlsBlon on Radiation Protection (1959)," Health PhviacB . 3!63 (1960). 61. Grundy, R. D. et al. , "Fallout Radionuclides in Milk, Total Diet and Human Bone Compared to Federal Radiation Council Estimates," Radioloaieal H6alth Data . 6:651-5 (1965). 62. United States Public Health Service, National Center for Radiological Health, "Radionuclide Levels in Milk, Total Diet, and Human Bone Compared to Federal Radiation Council Estimates, 1965, and 1966 Estimates." Radiological Health Data and Reports . 8:63-72 (1967). 63. Federal Radiation Council, Background Material for the Development of Radiation Protection Standards ; Protective Action Guides for Strontium-90 and Cesium-137 . Report No. 7, Washington, D. C. (1965). 64. Rivera, J., "Dietary Intakes and Body Burdens of Cesium-137," Radiological Health Data . 6:504-6 (1965).65. Gustafson, P. F., "The Relation Between Cesium-137 in Man and His Diet in the Chicago Area," Radiological Health Data . 6:719-22 (1965). 66. Coleman, J. R. , "Projected Values of Cesium-137 Body Burdens in Anaktuvuk Pass Eskimos for the Summer of 1965, Based on* Findings in Caribou Muscle." Radiological Health Data . 6:578-82 (1965). 67. Baarli, J. K. et al. , "Radiocaeaium and Potassium in Norwegians," Nature, 191:436-8 (1961). 68. Llden, Kurt, "Cesium-137 Burdens in Swedish Laplanders and Reindeer," Acta Radiol. . 56:237 (1961). 69. Hungate, F. P. et al . , "Radionuclides in Alaskan Eskimos," CONF640819-2:16-26 (1965). 70. Chandler, R. P. et al . , "Summary of Cesium-137 and Strontium-90 Concentrations Reported in Certain Alaskan Populations and Foodstuffs, 1961-1966." Radiological Health Data and Reports . 7:675-89 (1966). 71. Hanson, W. C. et al . , "Radioactivity in Northern Alaskan Eskimos and Their Foods, Summer, 1962." Health Physics . 10:421 (1964). 72. Miettinen, J, K. et al,, ''Ce8ium-137 and Potassium in Finnish Lapps and Their Diet," Radiological Health Data . 5:83-97 (1964). 73. Hanson, W. C. and H. E. Palmer, "Seasonal Cycle of Ce8ium-137 in Some Alaskan Natives and Animals ." Health Physics . 11:1401-6 (1965). 74. Hanson, W. C, "Ceaium-137 in Alaskan Lichens, Caribou, and Eskimos," Health Physics . 13:383-9 (1967).

PAGE 171

159 75. Fitzpatrick, D. et al . , "Cesium Body-Burdens in Alaskan Men,Spring, 19 66 . " Radiological Health Data and Rfepbr ts , 7:691-6 (1966). 76. Mlettinen, J. K. , "Concentration of Ce8ium-137 and Iron-55 Through Food Chains in Arctic and Subarctic Regions," CONF-660405-14 (1966). 77. Svensson, GBran K. and Kurt Liden, "The Transport of Ceslum-137 from Lichen to Animal and Man." Health Physics . 11:1393-1400 (1965). 78. Chandler, Robert P. and Samuel Wieder, "Radionuclides in the Northwestern Alaska Food Chain, 1959-1961 A Review." Radiological Health Data . 4:317-24 (1963). 79. Palmer, H. E., W. C. Hanson, B. J. Griffin, "Radioactivity Measured in Alaskan Natives, 1962-1964," Science, 147:620 (1965). 80. Palmer, H. E. et al. , "Cesium-137 in Alaskan Eskimos," Science. 142:64 (1963) . 81. Palmer, H. E. and R. W. Perkins, "Ceslum-134 in Alaskan Eskimos and in Fallout." Science . 142:66 (1963). 82. Division of Radiological Health, United States Public Health Service, "Radionuclides in Alaska Caribou and Reindeer, 1962-1964," Radiological Health Data . 5:617-9 (1964), 7:189 (1966), 8:290-2 (1967). 83. Bruce, Daniel W. et al. , "Cesium Body Burdens of Alaskan Men, Spring 1965." Public Health Reports . 80:949-53 (1965). 84. Witkamp, Martin, "Biological Concentrations of Cesium-137 and Strontium90 in Arctic Food Chains . " Nucl . Safety, 8:58-62 (1966). 85. "Monitoring of Radioactivity in Man," BNWL-36 (1966). 86. Bureau of Sanitary Engineering, Florida State Board of Health, "Radiological Background Monitoring Program," Reports No. 1-4 (19581960) . 87. Gllcreas, F. W. and G. B. Morgan, "The Role of the Public Health Laboratory in Radiological Science," Am. J. Pub. Health. 50 :No. 5 (1960) . 88. Morgan, G. B. and F. W, Gilcreas, "Radioactive.. Monitoring and Environmental Health," Onarterly J .. of Fla^ Acad^ of Sclj., 22:4 (1960) . 89. Morgan, G. B. et al. . Radioactive Fallout in Alachua Countjr., Leaflet No. 165, Eng. and Ind. Exp. Station, University of Florida (1963). 90. "Florida Water Sampling," Radiological Health Data and Reports, 6:44,640 (1965).

PAGE 172

160 91. "A Brief Review of the Public Health Service Radiation Surveillance Network," The Nature of Radioactive Fallout and It8 Ef facta of Man, 459 (1957). 92. "United States Public Health Service Radiation Surveillance Network," Radiological Health Data . 1;25 (1960). 93. Setter, L. R. et al. , "Air-Borne Particles Beta Radioactivity Measurements of the National Air Sampling Network— 1953-1959," AIHA Jj., 22:192-200 (1961). 94. Lockhart, Luther B., Jr. et al . , "Atmospheric Radioactivity Along the 80th Meridian (West) ," Radioactive Fallout from Nuclear Tests . CONF-765:477 (1965). 95. "80th Meridian (West) Program." Radiological Health Data (and Reports) , Vol. 1-8 (1960-1967). 96. Lockhart, L. B., Jr. etal., "Summary Report on Airborne Fission Products Along the 80th Meridian (West), 1957-1962." Radiological Health Data . 5:255-65 (1964). 97. Health and Safety Laboratory, United States Atomic Energy Commission, "Fallout in the United States and Other Areas," Radiological Health Data (and Rep6rts) , Vol. 4-8 (1963-1967). 98. Collins, W, R. , Jr., "The 80th Meridian Network." Radiological Health Data . 4:342-6 (1963). 99. "List of Environmental Sampling Networks for Analysis of Radioactivity in Soils," Radiological Health Data . l(No. 5) : 20-5 (1960). 100. Alexander, L. T; et al., "Radioisotopes in Soils: Particularly with Reference to Strontium-90." Radioisotopes in the Biosphere . University of Minnesota, Minneapolis (1960). 101. "United States Public Health Service National Water Quality Network" (or "Gross Radioactivity in Surface Waters of the United States"), monthly in Radiological Health Data (and Reports) . Vol. 1-8 (1960-1967) 102. Division of Environmental Engineering and Food Protection, United States Public Health Service, "Drinking Water Analysis Program," Radiological Health Data . Vol. 3 and 6 (1962 and 1965). 103. Consumers Union, "The Milk We Drink." Consumer Reports . March, 1959. 104. Lackey, J. B., Shellfish and Radioactivity . Leaflet No. 115, Eng. and Ind. Exp, Station, University of Florida, Nov., 1959. 105. Straub, Conrad et al . , "Radiochemical Analysis of Food," Radiological Health Data . 1:93-7 (1960). 106. "Selected Results from Total Diet Studies, May 1961-62," Radiological Health Data . 4:353-8 (1963).

PAGE 173

161 107. Michelson, Irving, "Radioisotopes in the 1964 Diet." Health Physics . 11:587-91 (1965). 108. Food and Drug Administration, Radiological Health Data . Vol. 1-5 (1960-1964). 109. "Radionuclides in Institutional Diet Samples," Radiological Health Data, 3:42-5 (1962). 110. Grundy, R. G. et al. , "Summary of Results of Institutional Total Diet Sampling Network." Radiological Health Data . 6:691-8 (1965). 111. Cromroy, H. L. et al. , "Uptake of Ce8iimi-137 from Contaminated Soil by Selected Grass Crops," Radiological Health Data and Reports (In Press) . 112. Thatcher, L. L. et al . , "Trends in the Global Distribution of Tritium Since 1961," Radioactive Fallout from Nuclear Tests . CONF-765:723 (1965). 113. Hartgering, Lt. Col. James B., "Comments." The Nature of Radioactive Fallout and Its Effects on Man . 725 (1957) . 114. Woodward, Kent T. et al. , "Human Counting Facility at the Walter Reed Army Institute of Research, Walter Reed Army Medical Center, Washington, D, C, " Fallout from Nuclear Weapons Tests . 1349:73 (1959). 115. Walter Reed ktmy Institute of Research, "Ce8ium-137 Levels in Humans," Radiological Health Data . 2:192-5 (1961). 116. Leitnaker, F. C. et al . , "Cesium-137 Burdens in Man, July, 1963, through August, 1964," Radiological Health Data . 6:227-9 (1965). 117. Roessler, Genevieve S., Whole-body Counter Laboratory, University of Florida, Personal Communication. 118. Department of Health, Education and Welfare, United States Public Health Service, Southeastern Radiological Health Laboratory, Montgomery, Alabama, Press Release, Sept., 1966. 119. Bolch, W. E. and E. H. Galbraith, Dept. of Bioenvironmental Engineering, University of Florida, Personal Communication. 120. Hairr, Graham, Divison of Radiological Health, Florida State Board of Health, Personal Communication, June 2, 1967, 121. Russell, R. Scott, "Surveys of Radioactivity in Human Diet," Radioactivity and Human Diet . Pergamon Press, Oxford, 469-87 (1966). 122. DeRuyter, A. W. and A. H. W. Aten, Jr., ^Gamma-Emitting Fallout Nuclides in the Netherlands Diet." Health Phyflics . 12:909-15 (1966).

PAGE 174

162 123. Thompson, J. C, Jr. and F. W. Lengeman, "Dietary Intake of Radionuclides: Effect of Consumption Patterns and Evaluation by Use of Integrating Samples," Radioactive Fallout from Nu6l6ar WfeApOns Tests . CONF-765:877 (1964). 124. Madahus, K. et al. , "Cesium-lS? in Milk, Meat, and Man in Norway, 1962-1965." Radioldgidal Health Data and Retiotts . 7:63-3 (1966). 125. Fredriksson, L. et al . , "Caeaium-137." Radioactivity and Human Diet . Pergamon Press, Oxford, 338-52 (1966) . 126. Ekman, L. as quoted by Fredriksson, L. et al. , "Caesium-137," Radioactivity and Human Diet , Pergamon Press, Oxford, 340 (1966). 127. Hood, Sam L. and C. L. Comar, "Metabolism of Cesium-137 in Rats and Farm Animals," Arch, of Biochem. and Biophy.. 45:423-33 (1953) . 128. "Off-Site Animal Investigation Project." Radiological Health Data . 2:89-96 (1961). 129. "Project Gnome." Radiological Health Data . 3:303-4 (1962). 130. Meat Inspection Division, U. S. Department of Agriculture, "Strontiian90 and Ce8ium-137 Content of Beef and Beef Products, 1960-1962," Radiological Health Data . 4:612 (1963). 131. Plummer, G. L., et al . , "Cesium-137 and a Population of Georgia WhiteTailed Deer," Paper Presented at the Second National Symposium on Radioecology, Ann Arbor, Michigan, May, 1967, to be published. 132. Setter, L. R. et al . , "Strontium-90 in Food A Summary of Results on Selected Foods in the United States, July, 1962 October, 1963," Radiological Health Data and Reports . 7:64-78 (1966). 133. Setter, L. R. , "Ce8ium-137 in Food A Summary of Results on Selected Foods in the United States, July, 1962 October, 1963," Radiological Health Data and Reports . 7:145-56 (1966). 134. Laug, E. P. and W. C. Wallace, "A Survey of Radioactive Residues in Foods Before and After 1945: Evidence of Possible Fallout Contamination," J. of Asso. of Off. Agri. Chem. . Vol. 42 (1959). 135. Laug, E. P. et al. , "Radioactivity in Foods II: Evidence of Fallout Contamination During 1958 and 1959." J. of Asso. of Off. Agri. Chem.. Vol. 44 (1961). 136. Food and Drug Administration, "Survey of Radioactivity in Food," Radiological Health Data . 3:476-81 (1962). 137. Food and Drug Administration, Vcesium-137 and Strontlum-90 in Foods, 1960-1962 . " Radiological Health Data . 4:81 (1963).

PAGE 175

163 138 Laug E. P., "Temporal and Geographical Distributions of Strontium90 aAd Ceaium-137 in Food . " Radiological H6alth Data. 4:448 (1963). 139. Bruce, .R.S.,' -Radionuclides in the United Kingdom Diet," Radiological Health Data and Reports.. 7:331-4 (1966). 140. Radiobiology Laboratory, United Kingdom Agricultural Research Council, "Radionuclides in United Kingdom Diet 1962," Radiological Health Data and Reports . 7:711-2 (1966). 141. Hvinden, T. , "Caesium-137 and Strontium-90 in Air, Precipitation, Soil, and Agriculture Products in Norway." Acta Radiol. . Suppl. 254:29 (1966). 142. Madshus, KJell, "Levels of Cesium-137 in Agricultural Products in Norway and in the Population, 1964-1965," Ac£«;lS^£ii» Suppl. 254:50 (1966). 143. Caupka, S. et al. , "Seasonal Variation in the Concentration of of Caesium-137 in Grass and Alfalfa," Nature, 213:1204-6 (1967). 144. "Selected Results from Total Diet Studies, February, 1963 June, 1964." Radiological Health Data . 6:700-3 (1965) . 145. Baratta, E. J. and E. R. Williams, "Radionuclides Levels in Teenage Diets A Comparative Study of Two Sampling Programs," Radiological Health Data . 6:37-40 (1965). 146. Food and Drug Administration, "Teen-ager Diet Survey," Radiological Health Data . 4:18-22 and 285-6 (1963). 147. Laug, E. P. et al . , "Total Diet Study: A. Strontium-90 and Cesium-137 Content," J^ of the Asso. of Off. Agric. Chem. . 46:4 (1963) . 148. Laug, E. P. and J. M. Dimitroff, "Radioactivity in Total Diet Samples," J. of the Asso. of Off. Agric. Chem. . 47:5 (1964). 149. "Tri-City Diet Study," Radiological Health Data (and Reports) . Vol. 2-8 (1961-1967). 150. Rivera, M. J., "Ce8ium-137 in Tri-City Diets," Radioloffical Health Data and Reports . 8:154-7 (1967). 151. Murthy, G. K., A. S. Goldin, J. E. Campbell, "Zinc-65 in Foods," Science . 4:659-60 (1960). 152. Van Dilla, M. A., "Zinc-65 and Strontium-90 in Food," Science, 4:65960 (1960). 153. Sax, M. E. and J. J. Gabay, "Occurrence of Mn-54 in Human and Bovine Livers." Health Physics . 11:585 (1965).

PAGE 176

164 154. Gabay, J. J., "Mn-54 in Freshwater Clams." Health Phyalca . 12:968-70 (1966) . I 155. SvensBon, 6. K. and K. Llden, "The Quantitative Acctmulatlon of Zr-95 + Nb-95 and Ba-140 + La-140 in Carpets of Forest Moss." Health Physics . 11:1033 (1965). 156. Johnson, J. E., D. W. Wilson, G. M. Ward, "The Appearance of lodine131 and Bariuin-Lanthanuin-140 in Fallout Due to the Second Chinese Nuclear Test," Radioldfeical Health DAta and Reports . 7:1 (1966). 157. Krieger, H. L. and D. Groche, "Occurrence of Scandium-46 and Cesitun144 in Fallout," Science, 131:40-1 (1960). 158. Perkins, R. W. and J. M. Nielsen, "Sodium-22 and Ce8ium-134 in Foods, Man, and Air," Nature . 205:866-7 (1965). 159. Liden, Kurt and Ingvar Andersson, "Caesiuin-134 in Man," Nature, 195: 1040-3 (1962). 160. Cigna, A. and Giovcelli, "Sodiuin-22 in Milk." Health Physics . 11: 1095-7 (1965). 161. DeBortolli, M. , P. Gaglione, A. Malvicini, "Some Data and Comments on Sodium-22 in Food Chains," Health Physics . 12:353-9 (1966). 162. Klement, Alfred W. , "Radioactive Fallout from Nuclear Detonations of February and April, 1960," Radiological Health Data . 1:7 (1960). 163. Branson, B. et al . , "Detection of Fallout from Chinese Nuclear Test of October 16, 1964, by the National Air Sampling Network," Radiological Health Data . 6:188-92 (1965). 164. Division of Radiological Health, United States Public Health Service, "Detection of Fresh Fission Product Material in Environmental Samples Following the Second Nuclear Detonation on the Chinese Mainland," Radiological Health Data . 6:5583-5 (1965). 165. Gold, S. et ^. , "Fallout from Chinese Nuclear Test of May 13, 1965," Radiological Health Data and Reports . 7:209-14 (1966). 166. Grundy, R. D. and D. R. Snavely, "Fallout from the Third Chinese Test May 9, 1966," Radiological Health Data and Reports . 8:301-16 (1967). 167. Muth, H. et al. , "The Normal Radium Content and the Radium-226/ Calcium Ratio of Various Foods, Drinking Water and Different Organs and Tissues of the Human Body." Health Physics . 2:239-45 (1960). 168. Michelson, Irving, "Radium-'226 in the Total Diet." Health Physics . 5:229^30 (1961).

PAGE 177

165 169. Mlnstry, K. B. et al . , "On the Radioactivity of Plants from the High Radiation Areas of the Kerala Coast and Adjoining Regions. II. Studies on the Uptake of Alpha and Gamma Emitters » " Health Physics . 11:1459 (1965). 170. Klement, Alfred W., Jr., "Natural Radionuclides in Foods and Food Source Materials," Radioactive Fallout . Soils, Plants, Foods, Man, Elsevier Publishing Co., N. Y., 113-55 (1965). 171. Harley, JohnH., editor. Manual of Standard Procedures . Health and Safety Laboratory, USAEC, NYO-4700 (1967). 172. Kahn, Bemd et al. , Rapid Methods for Estimating Fission Product Concentrations in Milk . Public Health Service Publication No. 999-RH-7 (1964). 173. Baratta, Edmond J. et al . , An Environmental Surveillance Laboratory for Radionuclide Analyses . Public Health Service Publication No. 999-RH-7 (1964). 174. Porter, C. R. et al.. Procedures for Determination of Stable Elements and Radionuclides in Environmental Studies . Public Health Service Publication No. 999-RH-lO (1965). 175. Falter, Kenneth, RadioACitive D6Cay Correction Factors . Public Health Service Publication No. 999-RH-12 (1965). 176. Kolde, H, E., Quality Control of Radioactivitv-Counting Systems. Public Health Service Publication No. 999-RH-15 (1965). 177. Ferri, Esther, Paul J. Magno, Lloyd R. Setter. Radionuclide Analysis of Large Numbers of Food and Water Samples . Public Health Service Publication No. 999-RH-17 (1965). 178. Phillips, Charles R. et al. , A Computer Program for the Analysis of Gamma-Ray Spectra by the Method of Least Squares . Public Health Service Publication No. 999-RH-21 (1966). 179. Inter laboratory Technical Advisory Committee, Sub-Committee on Environmental Surveillance, Routine Surveillance of RadioaOtivity Around Nuclear Facilities . Public Health Service Publication No. 999BH-23 (1966). 180. National Center for Radiological Health, RAdioassay Procedures for Environmental Samples . Public Health Service Publication No, 999RH-27 (1967) . 181. Branson, B. M. et ^d. , "High Sensitivity Low Background Gamma Spectrometry System-Design Through Initial Results," Health Fh2i:ilc8, 11:1083-90 (1965). 182. Wall, M. A. and A. S. Goldin, "Precision and Sensitivity of Gamma Spectrometric Measurements in Milk," Radiological Hfealth Data and Reports . 7:555-9 (1966).

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166 183. Boni, A. L., "Rapid Ion Exchange Analysis of Radioceslum in Milk, Urine, Sea Water, and Environmental Samples." Anal. Ch6m. . 38:89-92 (1966) . 184. Boni, A. L., "Improved Techniques for Environmental Sample Analysis," Health Physics . 9:1035-46 (1963). 185. Johnson, James E., Gerald M. Ward, Harold E. Stewart, "Interpretation of Gamma-Ray Spectra of Environmental Forage Samples." Health Physics . 12:37-42 (1966). 186. Ward, G. M. , J. E. Johnson, D. W. Wilson, "Determination of Fallout Radionuclides in Environmental Samples by Gamma-Ray Spectrometry," Radioisotope Sample Measurement Techniques in Medicine and Biology . International Atomic Energy Agency, Vienna (1965). 187. Mercer, E. R. , "Analytical Methods." Radioactivity and Human Diet . Pergamon Press, Long Island City, H. Y., 489-508 (1966). 188. Vegetable Crop Specialists, University of Florida, Vegetarian .. No. 52 (1960) . 189. Florida Department of Agriculture, Florida Agriculture Statistics Vegetables (1966). 190. Palmer, A. Z. , Meat Laboratory, University of Florida, Personal Communication. 191. Golden, Doyle, Chemistry Division, Florida Department of Agriculture, Tallahassee, Florida, Personal Communication. 192. Munks, Bertha, "Pesticide Residue ManuiSil," Florida Department of Agriculture . 1:100-200 (1965). 193. National Center for Radiological Health, "Procedures for Interpreting Gamma Spectra," Radioassay Procedures for Environmental Samples . Public Health Service Publication No. 999-RH-27, Section 1:46-54 (1967) . 194. Scheffe, H. , The Analysis of Variance . John Wiley and Sons, Inc., New York (1959) . 195. Watt, B. K. and A. L. Merrill . Composition of Foods . United States Department of Agriculture Handbook No. 8 (1963). 196. Broecker, W. S. et al. . "Strontium-90 Fallout. Comparison of Rates over Ocean and Land." Science . 152:639-40 (1966). 197. Ward, G. M. , J. E. Johnson, H. F. Stewart, "Ce8ium''137 Passage from Precipitation to Milk," Radioactive Fallout from Nuclear Weapons Test . CONF-765 (1965).

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167 198. Butson, Keith, Climates of the States Florida . United States Department of Commerce, Booklet No. 60-8 (1962). 199. "Reported Nuclear Detonations, Detonations, December, 1966," Radioloeical Health Data and Reports . 8:64 (1967). 200. Hawthorne, Howard A., "Fission Product Cycles in an Agricultural System," Radioactive Fallout from Nuclear Weapons Test, CONF-765(1965) .

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BIOGRAPHICAL SKETCH Charles Ervin Roessler was born May 1, 1934, in Elysian, Minnesota, where he attended elementary schools. He attended high school at Waterville, Minnesota, and received his diploma in 1951. He received his Bachelor of Arts degree from Mankato State College, Mankato, Minnesota, in 1955 with majors in biology and chemistry and a minor in mathematics. He attended the University of Rochester on a United States Atomic Energy Commission Fellowship and received a Master of Science degree in radiation biology there in June, 1956. He spent the stimmer months of 1956 at Brookhaven Laboratory, Long Island, New York, on an Atomic Energy Commission training program. From September, 1956, to September, 1958, he worked as a health physicist with the Nuclear Power Division of Curtiss-Wright Corporation at Quehanna, Pennsylvania. He returned to graduate work with an Atomic Energy Commission Fellowship at the University of Pittsburgh in September, 1958, and received a Master of Public Health there in June, 1959. He was employed as a radiological physicist at the Florida State Board of Health from July, 1959, to January, 1965, with supervisory responsibilities for radiological health in the Division of Radiological and Occupational Health. He began his graduate study at the University of Florida under a United States Public Health Service Fellowship in January, 1965. He is married to the former Genevieve Schleret of Owatonna, Minnesota, and they are the parents of six children. 168

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169 He is a charter member of the Health Physics Society and a member of the executive council of the Florida Chapter, Health Physics Society. He is also a member of the Conference on Radiological Health, the American Industrial Hygiene Association, the Florida Section of the American Industrial Hygiene Association, the American Conference of Governmental Industrial Hygienists, and the Air Pollution Control Association. He was certified in Health Physics by the American Board of Health Physics in 1961, was elected to associate membership in the Society of the Sigma Xi in 1959, and was elected to Who's Who Among Students from American Colleges and Universities in 1954-1955.

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This dissertation was prepared under the direction of the chairman of the candidate's supervisory committee and has been approved by all members of that committee. It was submitted to the Dean of the College of Engineering and to the Graduate Council and was approved as partial fulfillment of the requirements for the degree of Doctor of Philosophy. December 19, 1967 / ^!S(>^^uu>^ eail. College of Engineering Dean, Graduate School SUPERVISORY COMMITTEE Chairman 1 Co-chairman U-^ ^..v? hfkf/.:^^ ,9^, UNIVERSITY OF FLORIDA 3 1262 08666 436 3


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