FOR REVIEW ONLY NOT FOR RELEASE
Preliminary Report of the
Committee on Quality of Water
FLORIDA WATER RESOURCES STUDY COMMISSION
Eagene Brown, Chairman
John B. Miller
J. M. Pearce
William M. Beck, Jr.
Quality of Water Branch, U. S. G. S.
Florida State Board of Health
Florida State Board of Health and
Florida Engineering Society
Chemistry Dept., University of Florida
Florida State Board of Health
~ -Ir -------------1------ -
QUALITY OF NATURAL WATERS
Chemically pure water in nature is practically unknown. Even the falling
# fin contains gases and solids which are absorbed from the atmosphere. Water, upon
teaching the land and passing through the various phases of the hydrologic cycle,
continues its solvent action collecting both dissolved and suspended matter. It is
the kind and amount of these impurities that govern the quality of a given water. In
turn the quality often limits the beneficial uses which are planned for the water.
Topography and geology will influence the quality of water. Relief of the
land, amount of moisture already present and condition of the land surface, collec-
tively, will determine runoff rate (length of time that water contacts surface
materials). Erosive power of runoff water will also be determined thereby, and the
physical and chemical quality of the water will likely be affected.
Carbon dioxide and acids from decaying vegetation dissolved in water greatly
enhance the solution of calcium, magnesium, and heavy metals frequently found in
Streams generally exhibit an increase in color and sediment load and a
decrease in dissolved solids, during periods of high flow; these conditions are re-
versed during periods of minimum flow. Often this quality characteristic of surface
waters is most significant in determining the usefulness of a given source.
Conversely, the mineral content of ground water is relatively constant but
usually higher than surface waters. Condition, type and physical structure of geo-
logic formations affect the amount of solids dissolved. Primary characteristics of
ground water are an absence of color and suspended solids and a nearly uniform tem-
Man makes drastic changes in water quality for and during municipal and
industrial uses, then later returns the water, together with water-borne wastes, to
the land and surface streams. Agricultural activities, accelerated natural erosion,
flood control, and reservoir construction also affect water quality. In some coastal
areas man's uninformed activities have caused sea water infiltration into fresh ground
The number and type of possible impurities in natural waters is unlimited,
but geologic and topographic conditions generally restrict the actual number to rela-
tively few. Some important chemical and physical qualities, with their significant
effects are summarized in Table 1.
Iron and Manganese
L. Water Quality Characteristics and Their Effects.
A measure of the total amount of dissolved matter, usually
determined by evaporation. Excessive solids interfere in
most processes and cause foaming in boilers.
Causes scale in boilers and deposits on turbine blades.
Excessive amounts are cathartic and unpleasant to taste.
May pause scales.
High concentrations indicate pollution, cause methemoglobi-
nemia in infants, helps to prevent intercrystalline cracking
of boiler steel.
Excessive concentrations cause mottled tooth enamel, small
amounts prevent tooth decay.
Values below 7.0 indicate an acid water and a tendency for
the water to be corrosive toward metal.
On precipitation cause stains; unpleasant taste in drinking
water; scale deposits in water lines and boilers; interferes
in many processes such as dyeing and paper manufacture.
Table 1 (continued)
Calcium and Magnesium
The cause of hardness in water.
Unpleasant taste in high concentrations. Increases corrosive
nature of water.
Large amounts injurious to soils and crops, and humans with
Due to calcium and magnesium salts causes excessive soap
consumption, seals in heat exchangers, boilers, radiators,
pipes, and interferes in dyeing, textiles, food, paper and
other manufacturing processes.
Causes foaming in boilers and carryover of solids with steam,
embrittlement of boiler steel.
Stains products in process use, may cause foaming in boilers,
and is unsightly in drinking water.
Unsightly appearance in water, deposits in water lines,
process equipment and boilers.
EFFECT OF QUALITY ON WATER USE
The effect of water quality on its ultimate use varies widely, since
tolerance limits for the different impurities also vary greatly depending upon use
requirements. Quality requirements for one use might be objectionable in another cir-
cumstance. For instance, some well waters could very well be used without treatment
for ice manufacture, cooling water, beer or soft drink production but might be unsuit-
able for use as boiler feed water. Sea water may not be objectionable for use in
swimming pools but no one would want it for domestic purposes. A water free of objec-
tionable chemical constituents might be so contaminated bacteriologically that it would
be unsuitable for any normal use, industrial or domestic.
Water for most purposes is acceptable if it is clear, cool, soft, odorless,
noncorrosive, nonscale forming, palatable, free from pathogenic bacteria and other
organisms, has no physiological effects and is available in quantity and under suffi-
cient pressure to meet all flow rates. Most municipal supplies either meet these
requirements or treatment is arranged to minimize objectionable characteristics and to
satisfy consumer demands in respect to quantity and pressure.
Naturally, water for drinking and cooking purposes must be free of pathogenic
bacteria, protozoa and other disease-producing organisms. Algae and micro-organisms
must be absent or controlled, as otherwise they could impart offensive tastes and odors
Toxic inorganic and organic substances are not commonly found in natural
waters, but still we must be certain that they are absent or in such snall concentra-
tions as to be below dangerous levels. Arsenic, lead, selenium and hexavalent chreaium
met be at very low levels in water used for human consumption, and the same applies to
barium salts, metal gluocosides and a few other substances. Recommended upper levels
for these and many others in water used in public systems are given in the 1946 Drinking
Water Standards of the Public Health Service.
Some quality limits are set to avoid unpleasant tasting water, whereas others
are set to prevent physiological upsets. Waters containing dissolved sulfides (com-
monly called "sulfur" water), excessive amounts of iron, copper, chlorides (salt),
sulfates or large amounts of dissolved solids may be very distasteful to most people
but not necessarily harmful. However, waters high in magnesium, especially if sulfates
are also high, may have pronounced laxative effects.
Colored water is generally objectionable because we are accustomed to clear
water. Water containing iron may have a distinct metallic taste and also be objection-
able for most domestic and industrial uses due to the production of off-colored
Most surface waters and many ground waters require appropriate treatment
before the finished water is suitable for domestic or industrial uses. However,
treatment for one purpose may not be sufficient for another use, and the water must
be tailored to meet the use requirements. All waters should be analysed chemically
and bacteriologically before being used in any manner. Selection of the most suitable
water source may avoid costly corrective measures for the use contemplated.
Municipal. Water suitable for municipal and domestic use must come from
relatively uncontaminated fresh water sources. In order to define the suitability of
water supplies for human consumption, the U. S. Public Health Service many years ago
stated the maximum concentrations of chemical substances permissable in water supplied
on interstate carriers. These quality requirements for drinking water have been uni-
versally accepted and adopted by the Health Departments of the various states. In
addition to being clear, colorless, odorless, of pleasant taste, and free from toxic
salts, the chemical substances which may be present in natural or treated waters should
preferably not exceed the following concentrations:
Constituents Maximmn concentration
(Parts per million)*
Iron (Fe) and Manganese (Mn) combined 0.3
Fluoride (F) 1.5
Nitrate (N03) 44
Magnesium (Mg) 125
Chloride (Cl) 250
Sulfate (S04) 250
Dissolved solids 500 (1,000 permitted)
* A unit of measurement to indicate concentration. For example, 1 part per million of
a substance is equivalent to 8.3 lbs. of the substance uniformly distributed in 1
million gallons of water.
Although all approved public water supplies, whether obtained from ground or
surface sources, are chlorinated before delivery to consumers, many supplies require
extensive additional treatment for the removal of color, and iron, and the reduction
While the hardness of a supply is seldom the sole cause for its rejection, it
is frequently the characteristic that receives the most attention from both domestic
and industrial consumers. When soaps are dissolved in water they react with the calcium
and magnesium forming an insoluble "curd" which not only wastes the soap but also
interferes in practically all washing operations. The presence of excessive hardness
produces undesirable results in many industrial processes, especially in those opera-
tions requiring the use of large volumes of water.
The hardness data for the larger public supplies of Florida have been sumwa-
rized in Table 2, which has been extracted from Water Survey and Research Paper No. 6,
published in 1951 by the State Board of Conservation.
Table 2. Hardness of Delivered Water of Selected
Public Water Supplies in Florida 1950
Hardness in parts per million Number of cities
0- 50 3
51 150 65
151 250 19
Industrial. Industrial quality requirements for water for specific purposes
are about as varied as the number of purposes for which the water is needed. Conse-
quently, it is impossible to attempt any broad generalization or simplification on the
subject. One characteristic is important to all industries, however, and that is the
need for relatively constant concentrations of the various substances in the water
supply. Even if the quality of untreated water is poor it can generally be altered,
through proper treatment processes, to serve the need at hand. A uniform concentra-
tion of impurities in the process water then minimizes the attention and expense
required to operate the process.
Nevertheless, an industry will seek an area where the quality of water is
such that the cost of treatment is low. This factor undoubtedly contributes to the
industrial growth of extreme northwest Florida. The ground water of Escambia and Santa
Rosa counties is of exceptional quality. Analyses of water from municipal wells at
Pensacola have shown total solids concentrations of less than 20 parts per million.
It is also true, however, that availability of water is only of relative
importance and many other factors influence plant location. Within certain economic
limits, any available water can be altered so that its quality will meet the most
Agricultural. The quality requirements for water used in agriculture are
almost as diverse as those for industrial water, owing to the many uses of water in an
agricultural economy. In addition to the need for a safe and adequate supply of drink-
ing water for the farmer and his family, water may be required for sanitary purposes,
cleansing of dairy and other equipment, irrigation, and the watering of stock and wild-
Although the quality requirements for irrigation are in general less exacting
than those for domestic use, no single standard has been devised that will apply to
all areas of the country. The classification of irrigation waters as to "good" or "bad"
must take into account numerous factors, among which are: agricultural practices,
climate, nature of the soil, and crop tolerances. Good soil drainage may be a more
important factor than water quality, for even good waters on poorly drained land may
not produce good crops. On the other hand, relatively highly mineralized waters may
often be used successfully on open-textured, well-drained soils. However, since a good
soil may be removed from production by the unwise irrigation with water of poor quality,
a knowledge is required of the chemical quality of potential irrigation supplies.
Floridats waters have not been so investigated and classified.
Recreational and other. Consideration of water quality criteria from the
recreational and related viewpoints stems primarily from quality alterations by man
rather than from natural quality. Included among this category of beneficial use are
quality requirements for wildlife feeding and watering, propagation of fish and other
aquatic life, shellfish production, swimming and bathing waters, boating and esthetic
enjoyment, water power, and navigation. The variety of requirements for these bene-
ficial uses again prohibits generalization, but in each instance there are quality
limits which, if exceeded, will diminish or even destroy the usefulness of the water
for the purpose intended.
The constituents in water that are of most interest to this beneficial use
include dissolved oxygen, hydrogen sulfide, ammonia, suspended matter, toxicants,
acidity, and bacteria. For each impurity an excess or a deficit can alter the water
quality beyong nature's ability to repair within a reasonable length of time.
AVAILABLE WATER QUALITY DATA
In quality investigations of surface waters it is found that tributaries,
rainfall, and mineralization from ground and surface leeching provide a water of
rapidly changing mineral concentration. Because of the rapidity of these changes,
daily samples are almost a necessity in order to define the character of the water.
By obtaining samples this frequently and for an adequate period, concentration ranges
of the constituents may be established. In addition, extreme variations may be noted,
together with their causes, and allowances made accordingly in preparation for the
utilization of these supplies.
Underground movement of water is considerably slower than that of surface
water and consequently require less frequent determinations. The program necessary
for the proper study of ground water sources requires the collection of sufficient
samples to show the mineral content and temperature of water from the different forma-
tions; detection of changes in chemical quality with pumping and with season of the
year; evaluation of possible effects of inducted infiltration on the chemical quality
of the supply; exploration of possible sources of salt water encroachment or other
contamination as determined by certain constituents in solution; and the relation of
mineral concentration to direction of ground water movement and sources of recharge.
Following intensive studies of an area, sufficient index stations should be
maintained on a continuing basis for both surface and ground water locations. Thus,
alterations in the quality may be detected and harmful influences prevented whenever
Surface Water. Intensive studies of surface water quality have been made on
a few restricted areas of the state. One of the most comprehensive investigations to
date is that made in southeastern Florida during the seven-year period beginning in
1939. As a result of salt-water encroachment in the Miami area, together with a search
for available water supplies, investigations were made of the general Dade County area
including water sources up to and beyond Lake Okeechobee. The results of these findings
have been made available by the published report "Water Resources of Southeastern
Florida," Geological Survey Water Supply Paper 1255.
Other studies of somewhat lesser magnitude have been or are being conducted
in other areas of Florida. Figure 1 shows the current quality of water stations by
location and type.
In many instances correlations are made between certain chemical constituents
and discharge. When sufficient data are available, such correlations can be of con-
siderable value in showing the probable limits of concentration that might be expected
beyond those actually observed. When such correlations point out that at certain
discharge values excessive mineral concentrations are to be expected, preventative
measures such as the installation and maintenance of controls may provide a supply
that is adequate for most needs. An illustration of such correlations may be seen in
Figure 2, showing the relationship between discharge and selected quality character-
istics of the St. Johns River at Deland.
Ground waters. Increased demands on available water supplies with resultant
increases of mineralization from salt water encroachment and intrusion have directed
attention rather forcibly to the realization of the need for more information on
present and potential water sources. Specific studies have been made in some instances
to meet the immediate need, but for the most part, programming for the future is lack-
ing. Such planning is needed to ascertain proper planning and control of these
resources. Figures 20 and 21 of the Preliminary Report of the Ground Water Comaittee
show the areas where the water resources have been subjected to study and evaluation
both quantitatively and qualitatively. In addition the section on water pollution
describes the qualitative influence of municipal and industrial wastes on Florida's