What's a 'pico curie?'

Material Information

What's a 'pico curie?'
Alternate Title:
Kincart, Robert O. Radon: What's a 'pico curie?' Florida Environments
Kincart, Robert O. Radon ( Author )
Publication Date:
Physical Description:


Subjects / Keywords:
Radon ( jstor )
Soil science ( jstor )
Ionizing radiation ( jstor )
Spatial Coverage:
North America -- United States of America -- Florida


General Note:
Box 5, Folder 22 ( SF - SIGNIFICANT NUMBERS ), Item 17
Digitized by the Legal Technology Institute in the Levin College of Law at the University of Florida.

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Source Institution:
University of Florida
Holding Location:
Levin College of Law, University of Florida
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All applicable rights reserved by the source institution and holding location.


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Radon: What's a 'pico curie?' Fida
-- Environmental
by Robert O. Kincart, mineral formations. PEOPLE...
OGuedColbmt niTypically, Forida soils wil contain
LAKELAND one or two pCi per gram. In most
ADIATION IS AS OLD as the structures, the soil accounts for about are covered in every issue of
universe. The stars, as well as 90% of indoor radon. Radon moves
the earth, are radioactive. through air spaces in the soil and rock Florida Environments
Since the beginning of their existence, and can enter a building through Florida's Environmental
humans have been exposed to ionizing cracks or openings (sewer pipe, cracks Newsmagazine
radiation from natural sources. More in concrete, wall-floor joints, hollow
recently, man-made ionizing radiation concrete walls). The remaining 10% SUBSCRIBE TODA
such as x-rays and that from numerous comes from water, building materials,CRIE AY
radioactive materials have been intro- or the outdoor air. When released out-
duced. In addition, many of our con- doors, radon mixes with the outside L U i. K \J I \AE
summer products, such as smoke detec- air and is widely dispersed. Radon B
tors and luminous dials, contain entering a building is confined to a rel-
radioactive substances. atively small space. Once inside the
There are several ways to describe building, the radon will tend to remain E IRON
or measure ionizing radiation. The indoors (like an odor or any other in- ENVIR NM I
amount of radioactivity present in a door pollutant) because most struc-
substance is measured in units called tures are designed to keep heated or Spill Clean Up S
"Curies" one Curie is the approxi- cooled air from escaping. Tank Cleaning/Removal
mate quantity contained in one gram of Many different factors affect the ra- Ground Water Remediation
radium. This is an extremely large don concentration in a building. Dif- Environmental Consulting E
quantity, and in order to measure radi- fcrcnces in these factors can cause the FLORIDA 1
ation in the environment the unit of annual average indoor radon concen-
choice is the "picoCurie", or pCi, tration to be as much as 50 times great- 1-800-2
which is one one-trillionth of a Curie. er in one structure than in another.
Concentrations of radon gas in the air These variations make it very difficult _
are measured in picoCuries of activity to predict specifically which buildings _
per liter of air, or pCi/l. A special unit will have elevated indoor radon con- _
of measurement of the concentration of centrations.
radon decay products in the air, called It should be emphasized that radon
the "Working Level" (WL), was de- levels vary widely over time, and are ,
rived for measuring the exposure of influenced by many factors. These in- --
uranium to miners. At equilibrium, 4 elude: home ventilation, indoor and
pCi/1 of radon gas is equivalent to outdoor air temperature, wind speed,
0.02 WL of decay products. The av- rainfall, time of day, season of year, PartBSlbragePemit
erage background of natural radiation and barometric pressure. Risks of ex- *EPA D#FL980734
from radon decay products in Florida posure to radon are estimated on the
is about 0.0004 WL indoors. Howev- basis of long-term, average levels and RESOURCE
er, deposits of phosphate ore contain so the best test is one conducted over
elevated levels of uranium and radium, an extended period of time. The short- OF AMERI
and hence, more radon. Normally, term, four (4) day test, is only a P.O. Bo
these ore deposits are located 20 to 50 screening test, helpful in determining Tampa, Flo
feet or more below ground surface. whether or not additional study is Telephone: (
Radon escaping to the atmosphere nor- needed. Major decisions about risks, 24-Hour Emergency Respc
mally is minimal, as the time of pas- or about the need for radon reduction, Mulberry Operatio-
sage of the gas through the soil to the should only be made on the basis of
surface of the ground is sufficient that long-term tests, preferably a year, but
most radon decays in the soil and par- at least two to three months in length.
ticulate decay products are trapped. If In general, whenever a screening
the land has been mined and then re- measurement is in excess of 4 pCi/1,
claimed, there is a mixing of the layers longer-term studies are recommended.
of the soil, and if more of the ore ma- This article contains information. ,e
trial is left closer to the surface, more supplied by the United States Environ-
radon may escape. This is. true also mental Protection Agency, Office of
for unmined land with near-surface Radiation Programs, Washington, ,"
Robeit0. Krr is a 4ncal in American Co- D.C. and the Florida Institute of Phos-
p5ane Tedhnoogies, Inc., i Lkeland. phate Research, Bartow, Florida, Ra- J
diation and Your Environment. _

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