 |
 |
 |
 |
 |
 |
|
|||
 |
 |
 |
|||||||
| Copyright © 2012. National Academy of Sciences. All rights reserved. Terms of Use and Privacy Statement |
Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 23
The Extent of
Groundwater Contamination
in the United States
1
VERONICA I. PYE and JOCELYN KELLEY
The Academy of Natural Sciences of Philadelphia
The mobility of our society and the distribution of industry and
agriculture depend on an available supply of clean water; never-
theless instances of groundwater contamination have been found
in most sections of the country (Kerns, 1977; U.S. Environ-
mental Protection Agency (U. S. EPA), 1980a]. For the purpose
of this chapter, groundwater contamination will be defined as
the addition of elements, compounds, and/or pathogens to water
that alter its composition.
One of the major difficulties with groundwater contamination
is that it occurs underground, out of sight. The pollution sources
are not easily observed nor are their effects often seen until
damage has occurred. There are no obvious warning signals
such as fish kills, discoloration, or stench that typically are early
indicators of surface-water pollution. Where contamination af-
fects pumping wells, some indications may occur, although
many commonly found contaminants are both colorless and
odorless and occur in low concentrations. The tangible effects
of groundwater contamination usually come to light long after
the incident causing the contamination has occurred. This long
lag time is a major problem.
Groundwater can be contaminated by a variety of com-
pounds, both of natural origin and man-made. Contamination
due to man has occurred for centuries, but industrialization,
urbanization, and increased population have greatly aggravated
the problem in some areas.
A contaminant usually enters the groundwater system from
the land surface, percolating down through the aerated soil and
unsaturated (vadose) zone. The root zone may extend 2 or 3 ft
into the soil, and many reductive and oxidative biological pro-
cesses take place in this zone that may degrade or biologically
change the contaminants. Plant uptake can remove certain heavy
metals; microbial fixation and other biological processes can
23
also remove a fraction of the contaminants the size of the
fraction being dependent on the nature of the contaminant.
Deeper below the root zone, which consists mainly of humus
and weathered rocks, there is a reduction in such biological
processes. Attenuation may occur by surface adsorption, cat-
ions in the contaminant being attracted to the negative charge
on clay particles. Soils have a cation exchange capacity. Other
contaminants may be removed by complexing with insoluble
organic matter, which gives rise to complexed humic acids.
Microbial action may influence redox potentials and cause the
release of inorganic ions during decomposition (Braids, 1981).
The susceptibility of different contaminants to differential at-
tenuation varies.
Once in the aquifer, a contaminant will move with the
groundwater at a rate varying between a fraction of an inch to
a few feet per day, forming, under certain idealized conditions,
an elliptical plume of contamination with well-defined bound-
aries. This dispersion process causes a spreading of the solute
in a longitudinal flow direction and also transverse to the flow
path (Chapter 2; Freeze and Cherry, 1979~; thus the plume
will widen and thicken as it travels. Attenuation of the con-
taminants in the aquifer may take place through dilution, vol-
atilization, mechanical filtration, precipitation, buffering, neu-
tralization, and ion exchange. Diffusion and dispersion will
bring contaminants into contact with material that may retard
their progress; thus attenuation may vary with the time and
distance traveled. Unless the plume is blocked it will usually
reach points of groundwater discharge such as streams, wet-
lands, lakes, and tidal waters (Miller, 1981~. The shape of the
plume will vary according to the continuity and duration of the
source of contamination. Dispersion tends to dilute the con-
taminants; however, concentrations of contaminants are typi-
OCR for page 24
24
cally much higher in groundwater than in surface water (Miller,
1981).
Groundwater is a major natural resource in the United States
and is often more easily available than surface water. Between
40 and 50 percent of the population depends on groundwater
as its primary source of drinking water (U. S. Water Resources
Council, 1978a; U.S. EPA, 1977~. Groundwater delivered by
community systems supplies 29 percent of the population, and
a further 19 percent has its own domestic wells. About 95
percent of the rural population is dependent on groundwater
for drinking purposes. Approximately 75 percent of American
cities derive all or some of their supplies from groundwater
(Leopold, 1974~. The states vary in their dependence on
groundwater. Approximately 92 percent of New Mexico's pop-
ulation uses groundwater for drinking water as compared with
30 percent of Maryland s population (U.S. EPA, 1977~. West
of the Mississippi, in the area where irrigated agriculture is
prevalent, the states depend heavily on groundwater, whereas
the humid eastern portions of the country are less dependent.
In 1980 the fresh groundwater withdrawals for the United States
totaled 88.5 billion gallons per day, of which 68 percent was
used for agricultural irrigation (U.S. Geological Survey Water
Information Service, unpublished data).
SOURCES OF GROUNDWATER
CONTAM INATION
There are three main ways in which the chemical composition
of groundwater may be changed. The first is due to natural
processes. Mineralization can result from leaching, especially
in arid areas. Evapotranspiration can further concentrate salts
in the remaining water. In the arid southwest and southcentral
areas of the United States, natural leaching has been identified
as the most prevalent source of contamination (Fuhriman and
Barton, 1971; Scalf et al., 1973~. Chlorides, sulfates, nitrates,
fluoride, and iron commonly occur in localized deposits, and
their concentration in groundwater may exceed U.S. EPA
standards. Arsenic and radioactivity from uranium ore also may
cause local problems.
The second category of sources of contamination is that due
to man's waste-disposal practices. The 1977 Report to Congress
on waste-disposal practices and their effects on groundwater
(U.S. EPA, 1977) provided estimates of the sources and the
extent of groundwater contamination. At the time the report
was compiled, definitive data on waste-disposal practices often
were not available, and indeed this is frequently the case today.
Implementation of the Resource Conservation and Recovery
Act of 1976 would be expected to affect waste-disposal prac-
tices, but such recent data or estimates are not available. Sources
of contamination involve all aspects of our lives, including man-
ufacturing and service industries, agriculture, and government.
It is estimated that over 30,000 chemicals are now being used
and distributed through the environment and that an additional
1000 are being added each year (Weimar, 1980~. Besides the
1977 Report to Congress, a report by the Environmental As-
sessment Council of The Academy of Natural Sciences of Phil-
VERONICA I. PYE and JOCELYN KELLY
adelphia (Pye et al., 1983) assessed the various sources of
groundwater contamination. Contaminant sources from waste-
disposal practices include individual sewage-disposal systems;
land disposal of solid wastes; collection, treatment, and disposal
of municipal wastewater; industrial and other wastewater im-
poundments; land spreading of sludge; brine disposal associ-
ated with the petroleum industry; disposal of mine wastes;
deep-well disposal of liquid wastes; disposal of animal feedlot
waste; and disposal of high- and low-level radioactive wastes
resulting from a variety of activities. All of these potential sources
of contamination are direct effects resulting in natural and syn-
thetic substances entering the groundwater because of human
activities (Matthess, 1982~.
The third category of sources is also the direct result of
human activities but is unrelated to waste-disposal practices.
It includes accidental spills and leaks, agricultural activities,
mining, highway de-icing salts, atmospheric contaminants and
acid rain, surface water, improperly planned groundwater de-
velopment leading to saltwater intrusion, and improper well
construction and maintenance.
Groundwater pollution problems and their sources have been
the object of numerous studies. An incomplete, but illustrative,
listing would include Fuhriman and Barton (1971), Scalf et al.
(1973), Miller et al. (1974), van der Leeden et al. (1975), Keeley
(1976), Miller et al. (1977), U.S. EPA (1978a, 1978b, 1980a),
U.S. General Accounting Office (1978, 19807; U.S. Water Re-
sources Council (1978a, 1978b, 1978c), Jackson (1980), and Pye
et al. (1983~.
SEVERITY OF GROUNDWATER
CONTAMINATION
In determining the overall magnitude of the national problem,
defining severity poses some difficulty. The definition may be
approached in several ways.
· If the contaminants in the groundwater exceed the interim
standards set for drinking water, then the problem could be
said to be severe, depending on the extent to which the con-
tamination exceeds the standard, if the intended use is for
drinking water. If the groundwater was not intended for drink-
ing, then the problem need not be severe. It should be noted
that the interim standards do not cover the many synthetic
chemicals that can often be found in water. (See proposed
rulemaking for volatile synthetic organic chemicals published
in the Federal Register, March 4, 1982.)
· The number of persons affected by contamination might
be taken into account. Thus the contamination of an aquifer in
the vicinity of a municipal well field would be of more concern
than contamination occurring in an isolated, sparsely populated
area.
· In terms of a single aquifer, the severity of contamination
may be related to the percentage of the aquifer contaminated
by point or nonpoint sources.
· Nationwide, the severity of the problem may be indicated
by the percentage of the available groundwater that is affected.
OCR for page 25
The Extent of Groundwater Contamination
· A different measure of severity might be obtained if the
volume of known and suspected contaminated plumes of
groundwater is expressed as a percentage of the nationwide
groundwater reserves.
· The degree of hazard posed by the contaminants varies
according to the volume discharged, toxicity, persistence, and
concentration and would be affected by how the contaminants
move in the aquifer.
Thus severity could depend on one or a combination of the
following parameters: concentration, persistence, and toxicity
of the contaminants; the number of people affected if the con-
taminated aquifer is a source of drinking water; and the per-
centage of the available groundwater (both locally and region-
ally) affected by such contamination. Interwoven with each of
these factors would be the economic cost of finding an alter-
native source of water if the contamination renders the ground-
water unfit for its previous or future uses or if treatment of the
water before use is not possible.
Many of the data required for these methods of assessing
severity of contamination in quantitative terms simply are not
available. The U. S. EPA (1980b) in the appendixes to the plan-
ning workshops to develop recommendations for a groundwater
protection strategy accurately summarized the sort of infor-
mation that is available from existing reports and studies, namely
documentation of a large number of contamination incidents,
identification of important sources of contamination, deter-
mination of the mechanisms of contamination, in-depth studies
of some contamination incidents, and surveys of the number
of certain contamination sources nationwide. The U.S. EPA
(1980a) recognized the usefulness of conducting a nationwide
survey at randomly selected sites to obtain an estimate of con-
tamination but ruled out this possibility because of the expense
of drilling and water sampling and the long time required.
Instead the U. S. EPA adopted a second approach of estimating
the number of sources of contamination and the amount of
contamination per source. The agency obtained an order-of-
magnitude estimate of the extent of the problem and utilized
existing information, both qualitative and quantitative. Such
assessments serve a useful purpose but only when their in-
herent flaws are kept in mind. Using information and estimates
for only two sources of contamination landfills and surface
impoundments and whether they are sited over usable aqui-
fers, the length of time they have been operating, and the
volume of available groundwater in storage, the U.S. EPA
(1980b) estimated that between 0.1 and 0.4 percent of the
usable "surface" aquifers are contaminated by industrial im-
poundments and landfill sites. The U.S. EPA cautioned that
this is a nationwide estimate and that the two types of disposal
sites used are usually found in areas of significant industrial
and domestic water use and that the problem could be exac-
erbated by the area's dependence on groundwater. The U.S.
EPA, although considering landfills and impoundments to be
the most important sources, also evaluated secondary sources
such as subsurface disposal systems (septic tanks) and petro-
leum exploration and mining and concluded that such sources
had contaminated about 1 percent and 0.1 percent, respec-
25
lively, of the nation's usable aquifers. The U.S. EPA (1980b)
therefore concluded that at present nearly 1 percent by area
of the usable "surface" aquifers in the United States may be
contaminated by these four activities and that the areas of
contamination will increase with time. It did not include an
estimate of the percentage of available groundwater contami-
nated by man's activities unrelated to waste disposal.
Lehr (1982) recently completed another independent esti-
mate, assuming a total of 200,000 point sources. Using faster
rates of contaminant spread over a longer period of time, Lehr
considered this to be a "worst-case" estimate. He arrived at a
range of between 0.2 and 2 percent. He concluded by stating
that no matter how liberal or conservative the estimate, the
fraction of polluted groundwater is small. This raises the ques-
tion of how to determine the salience of the problem. Should
contamination of 1-2 percent of our usable "surface" aquifers
be considered a minor or a serious problem? Obviously, for
those immediately affected, it is a serious problem. Also there
are many regions where the contamination could exceed 2
percent as the contamination is not uniform geographically.
Lehr (1982) optimistically predicted that the initiation of new
sources of pollution from waste disposal could be eliminated
in 10 yr by careful siting and facility design and operation and
that by taking these steps 98 percent of our available ground-
water could remain unpolluted. However, this does not mean
that existing sources will not continue to produce contamina-
tion.
Little information is readily available concerning the size of
the population affected by well closings due to groundwater
contamination. There are well-documented cases of well clos-
ings in South Brunswick, New Jersey (Geraghty and Miller,
Inc., 1979~; New Castle County, Delaware (Frick and Shaffer,
undated); and Long Island, New York, and California (Council
on Environmental Quality, 1981~. About 3 million people have
been affected by well closings, both municipal and domestic,
in these four states alone. Thus at present it is difficult to make
useful judgments on the severity of groundwater contamination
based on the number of people affected.
The types of chemicals that emanate from anthropogenic
sources of contamination are varied. They range from simple
inorganic ions such as nitrate (from septic tanks, feedlots, and
fertilizer use>, chlorides (from highway de-icing salt, saltwater
intrusion, certain industrial processes), radioactive materials
and heavy-metal ions (e.g., chromium from plating works) to
complex organic compounds resulting from manufacturing and
industrial activities and some of which are found in household
cleaning fluids. The chemical composition of wastes deposited
in landfills or surface impoundments is often known. Never-
theless when the constituents of such wastes interact, new
compounds may be formed that would not appear on the orig-
inal waste content inventory. Many industrial waste-disposal
practices involve stabilization of waste, thereby rendering it
less chemically active, but leachate production may still alter
some of these chemicals. The degradation of contaminants by
microbial organisms in the soils also changes the chemical com-
position, thus making it almost impossible to predict precisely
what contaminants reach the aquifer.
OCR for page 26
26
REGIONAL ASSESSMENTS OF GROUNDWATER
CONTAMINANTS IN THE UNITED STATES
In the 1970s the U.S. OPT ^~i~i^~1 fifth '-=i^~1 O~e
~ ~ ~ ~ ~V1111111~1~11~ 11 V ~ 1 ~~AVI1~1 "~O—
~ ~ ~ . .^
ment reports. They summarized the geology, major aquifers,
natural groundwater quality, and major pollution problems for
each region. The reports were completed for Arizona, Califor-
nia, Nevada, and Utah (Fuhriman and Barton, 1971), the south-
central states (Scarf et al., 1973), the Northeast (Miller et al.,
1974), the Northwest (van der Leeden et al., 1975), and the
Southeast (Miller et al., 1977~. Three additional reports were
to have covered Alaska and Hawaii, the Great Lakes area, and
the northcentral region, but these were not completed. The
findings for the principal sources of contamination in the five
VERONICA I. PYE and JOCELYN KELLY
regions are shown in Table 1.1. The assessment of the relative
importance of the sources of contamination may have changed
recently owing to a greater knowledge of the occurrence of
toxic organic chemicals in groundwater. Nevertheless, at the
time the U.S. EPA reports were completed, contamination
resulting from natural processes unrelated to man's activities
was considered to be of most concern in the arid southcentral
and southwestern states. The extensive irrigation that trans-
formed parts of the Southwest into a major crop-producing area
was considered to have caused problems from irrigation return
flow. Such problems would involve an increase in nitrate con-
centrations from fertilizer use, an increase in pesticide content,
and leaching of salts. The slow rate of recharge of many of the
aquifers in this area, coupled with extensive groundwater with-
TABLE 1.1 Sources of Groundwater Pollution throughout the United States and Their Prevalence in Each Regiona
Source Northeast Northwest Southeast Southcentral Southwest
Natural Pollution
Mineralization from soluble aquifers
Water from fault zones, volcanic origin
Evapotranspiration of native vegetation
Aquifer interchange
Groundwater Development
Connate water withdrawal
Overpumping/land subsidence
Underground storage/artificial recharge 4
Water wells
Saltwater encroachment
Agricultural Activities
Dryland farming
Animal wastes, feedlots
Crop residues, dead animals
Pesticide residues
Irrigation return flow
Fertilization
1
4
3
4
4
4
4
4
3
3
2
2
16
2
1
4
3
2
2
2
3
3
4
1
4
4
1
2
Mining Activities 2 2 3 2
Waste Disposal
Septic tanks/cesspools 1 1 2 2 1
Land disposal, municipal and 3 2 2
industrial wastes
Landfills 1 3 1
Surface impoundments 2 1 3
Radioactive waste disposal 3
Injection wells 2 4 2
Disposal of oil-f~eld brines 1 1
Miscellaneous
Accidental spills 2 3 1 3 2
Urban runoff 3
Highway de-icing salts 1 4 4
Seepage from polluted surface waters 3 4 3
Buried pipelines and storage tanks 1
Abandoned oil and test wells 1
Petroleum exploration and development 3 4
aNortheast includes NY, NJ, PA, MD, DE, and New England; southeast: AL, FL, GA, MS, NC, SC; northwest: CO, ID, MT, OR, WA, WY;
southwest: AZ, CA, NV, UT; southeentral: AR, LA, NM, OK, TX. Reports not completed for Great Lakes and North Central regions, AK, and
HI.
Numbers indicate degree of contamination: 1, high; 2, medium high; 3, medium low; 4, low.
OCR for page 27
The Extent of Groundwater Contamination
drawals, has led to groundwater overdrafting and associated
changes in groundwater quality and increased pumping costs.
The southcentral region, the most important area for petroleum
production, had a major problem with oil-field brines contam-
inating groundwater. Because of their sheer numbers and den-
sity, individual septic tank systems were considered the main
cause for concern in the Northwest, Northeast, and Southeast.
Contamination from septic tanks would result in elevated levels
of nitrate. More recently, widespread use of septic tank clean-
ers containing decreasing agents such as trichloroethylene has
resulted in groundwater contamination by synthetic organic
chemicals (Council on Environmental Quality, 19811. The U. S.
EPA assessments further identified the importance in the
Northeast and the Southeast of problems associated with in-
dustrial development, namely leakage from buried pipelines
and storage tanks and landfills and impoundments. Most of the
U.S. EPA assessments were completed before the attendant
publicity of Love Canal and the Valley of the Drums had made
public the potential threat of such dump sites and thus spurred
further investigations. All the reports were completed before
the U. S. EPA's Surface Impoundment Assessment (U. S. EPA,
1978a) made available the number of such potential sources of
contamination.
Keeley (1976) concluded from the U.S. EPA regional as-
sessments that problems indigenous in one area may not occur
in another but that several sources of groundwater contami-
nation occur at a high or moderate degree of severity in each
area studied. He noted that the four pollutants most commonly
reported were chlorides, nitrates, heavy metals, and hydro-
carbons but that this may merely be a reflection of the moni-
toring practices. Sampling for organic chemicals is not routine
and is usually expensive, although these chemicals are almost
always associated with municipal and industrial wastes. Keeley
(1976) also made the point that the rank-ordered problems in
the five regions were not selected on the basis of statistical
information as such information was not available. The prior-
ities were established empirically on the basis of the experience
of the authorities and individuals who had worked in the five
regions.
STATE SUMMARIES OF KNOWN INCIDENCES
OF CONTAMINATION
Recent federally mandated surveys under the Safe Drinking
Water Act have produced more information concerning the
number of potential sites where groundwater contamination
might occur (U.S. EPA, 1978b). In addition, many individual
states have recently undertaken inventories of their ground-
water contamination case histories. However, no systematic
national sampling survey has been carried out, a necessary step
for making an accurate appraisal and quantitative evaluation of
the extent of contamination.
The Environmental Assessment Council (Pye et al., 1983)
conducted a survey in 1981-1982 of groundwater contamination
incidents to investigate further whether additional information,
collected over the last few years, could cast more light on
groundwater problems in terms of severity and patterns of
occurrence. Data were collected on known incidents of con-
27
lamination from all the states by contacting each state and
requesting information on case histories of contamination if it
was available. The information received varied in usefulness,
some states having completed inventories and others having
just started or still in the process of documentation. Several
states were chosen to serve as examples in the report partly
because they had the most information about case histories of
groundwater contamination and because oftheir differing levels
of industrialization, agricultural activity, population density,
dependence on groundwater, and climatic conditions. The states
chosen were Arizona, California, Connecticut, Florida, Idaho,
Illinois, Nebraska, New Jersey, New Mexico, and South Car-
olina.
For the purpose of this assessment, the contaminants were
divided by source rather than constituents as these were not
always specified. Sources included industrial and manufactur-
ing waste products, petroleum products, landfill leachate, chlo-
rides, and organic wastes. Industrial and manufacturing prod-
ucts and wastes may be liquid or solid. Wood processing plants
were included in this category. Where the wastes were spec-
ified as petroleum or its derivatives the case histories were
included under that category. Petroleum products included
home heating oil, aircraft fuel, and gasoline. Landfill leachate
would be derived from solid, semisolid, or liquid waste of either
municipal or industrial origin. Chlorides were usually desig-
nated as originating from highway de-icing salts, agricultural
return flow, oil field brines, and/or saltwater intrusion. Organic
wastes included those, for example, derived from plant, animal,
or human wastes and those from feedlots, dairy barns, fruit
and vegetable processing plants, and sewage.
The discovery of groundwater contamination is not an end
in itself, and there are many remedial actions, direct and in-
direct, that can be taken to alleviate or reduce the problem,
even though these are often costly. Direct remedial actions
include actual cleanup of a contaminated site by soil removal,
pumping and treating contaminated water, or artificially re-
charging a contaminated aquifer; preventing further spreading
of contamination by building artificial barriers; and eliminating
sources of contamination by removing the contaminants or clos-
ing dumping sites. Indirect remedial actions include monitor-
ing, providing new water supplies, taking legal action, and
installing filtering mechanisms to keep contaminants out of the
water supply.
It should be emphasized that the case histories used in this
survey only indicate the potential magnitude of the problem
rather than the actual magnitude. Because the information deals
only with specific incidents, it usually only provides an indi-
cation of the range and importance of point sources but not of
all nonpoint sources. Where point sources were documented
and known to be of importance, an analysis of them is also
given.
Arizona
Arizona uses 4800 million gallons per day (mad) of groundwater,
which is 61 percent of its total water use (Fuhriman and Barton,
1971~. The state is divided into five groundwater basins: the
Upper and Lower Santa Cruz, White Mountain, Salt River
OCR for page 28
28
Valley, and Upper Salt River Basins (Arizona Division of En-
vironmental Health Services, 1979~. The Upper and Lower
Santa Cruz Basins and the Salt River Y alley all comprise an
area known as the Basin and Range Lowlands Province, where
the two major population centers of Arizona are located Tuc-
son and Phoenix. This area uses the most groundwater in the
state and has the highest potential for contamination.
Few cases of groundwater contamination are known to have
occurred a total of 23 incidents (Arizona Division of Envi-
ronmental Health Services, 1979; Hadeed, 1979; Lemmon,
1980; Robertson, 1975; Schmidt, 1972; U.S. EPA, 19811. All
of them threatened or affected the water supplies. The most
common source of contamination was industrial wastes (7 cases)
closely followed by landfill leachate (6 cases) and human and
animal wastes (6 cases). Each of the incidents involving human
and animal wastes led to outbreaks of disease. The incidents
were discovered, for the most part, by investigation, and in
only 6 of the cases was some sort of remedial action taken.
California
California uses more groundwater than any state in the na-
tion approximately 13,390 mad (California Department of
Water Resources, 1975~. Groundwater supplies about 40 per-
cent of the state's water needs. The largest groundwater res-
ervoir underlies the Central Valley Region, which occupies 10
percent of California's land area and includes the San Joaquin
Valley (Thomas and Phoenix, 1976~.
Overall groundwater quality is considered good and bene-
ficial for all uses (California Department of Water Resources,
1975~. There is no readily accessible complete inventory of case
histories of groundwater contamination available in California,
but some information on general and persistent contamination
problems in the state will be summarized. The data often do
not refer to specific cases of contamination but to generalized
occurrences.
Six general statewide groundwater problems of present or
potential concern have been identified (California State Water
Resources Control Board and Regional Water Quality Control
Boards, 1980~:
1. Increasing nitrate concentrations from various sources are
a current problem in some areas and a potential problem in
other areas. Animal wastes are one potential source of nitrate
contamination. In 1968, beef plus dairy cattle numbered almost
1,900,000 head, most being fed on the open range (Fuhriman
and Barton, 1971~. Poultry numbered 260 million, and the hog
population was 150,000 head.
2. Groundwater overdrafting has resulted in seawater intru-
sion of the 262 coastal groundwater basins (Fuhriman and Bar-
ton, 1971), mineralization due to recirculation or percolation
of used, and induced connate water migration. In the Los
Angeles area, three barriers have been constructed against
seawater encroachment. Overdrafting has also resulted in land
subsidence, which has been most severe in the San [oaquin
Valley, where subsidence in excess of 20 feet has occurred in
some areas (Fuhriman and Barton, 1971~.
VERONICA I. EYE and JOCELYN KELLY
3. Lack of officially designated hazardous-waste dump sites
has resulted in illegal dumping. Many rubbish sites are not up
to regulation. Fuhriman and Barton (1971) identified 207 legal
sites with inadequate control over surface drainage.
4. Percolation ponds for handling industrial and military wastes
are often inadequate for the types of wastes being disposed.
Oil-field brines and brines from water softener regeneration
plants are particularly troublesome (California Department of
Water Resources, 1975~.
5. Crop dusting operations have resulted in numerous sources
of pesticides having potential to reach groundwater.
6. The design of proper monitoring wells may be the biggest
roadblock to the process of establishing waste-discharge re-
quirements.
Connecticut
Connecticut uses little groundwater to meet its freshwater
needs 116 mad representing 8.2 percent of its total water
use (Handman et al., 1979~. Nearly one third of the ground-
water used (34.2 mad) goes for public and municipal supply;
the rural domestic or private well supply comes entirely from
groundwater, about 49.0 mad; 30.8 mad is used by industry.
The remaining 1.2 mad is used for livestock, irrigation, and
miscellaneous uses.
Connecticut provided details of 64 cases of groundwater con-
tamination (Miller et al., 1974; Lindorff and Cartwright, 1977;
Handman et al., 1979; Handman and gingham, 1980; U.S.
Congressional Research Service, 1980; U.S. EPA, 1981), 37
(58 percent) of which affected the water supplies. In addition,
Rolston et al. (1979) mapped 450 wells known to have produced
contaminated water, and Miller et al. (1974) reported that "sev-
eral dozen" wells were contaminated by saltwater intrusion in
the Long Island Sound area. The main reported or known
contamination problem stems from industrial or manufacturing
products and wastes, which account for 44 percent of the cases.
The primary means of detection was by well contamination.
No remedial action was reported for over 70 percent of the
cases.
Florida
Florida is a major user of groundwater, requiring more than
3000 mad in 1975 representing 18 percent of its total water
use. In 1970, groundwater use was 760 mad for public water
supply, 180 mad for rural uses, 1300 mad for irrigation, and
710 mad for industrial uses (Miller et al., 1977~.
Florida recently completed an inventory of its known cases
of groundwater contamination, and 92 cases were reported
(Miller et al., 1977; Florida Department of Environmental Reg-
ulation, 1980, 1981a, 1981b; U.S. EPA, 1981~. Of these, 63
percent affected or threatened water supplies. In fact, 50 per-
cent of the cases were discovered via contamination of wells.
The most important sources of groundwater contamination are
chlorides from saltwater intrusion and agricultural return flow
and industrial/manufacturing products or wastes, which ac-
counted for a total of 72 percent of the cases. Of all the cases,
OCR for page 29
The Extent of Groundwater Contamination
29
only 35 percent of them have had any kind of remedial action Fifty-eight cases of contaminated groundwater have been
applied. At the time these date were supplied, Florida was still documented for Illinois (Walker, 1969; Lindorff and Cart-
in the documentation phase of assessing its reported incidents
of groundwater contamination.
Idaho
In 1975, Idaho used 5600 mad of groundwater, representing
31 percent of the total water used in that state (Lehr, 1981~.
Fourteen percent of the total groundwater used in Idaho goes
to irrigation (van der Leeden et al., 1975~.
There are relatively few documented case histories of
groundwater contamination in Idaho (van der Leeden et al.,
1975; Lindorff and Cartwright, 1977; U.S. EPA, 1978a, 1981)
but several potential sources of contamination to be concerned
about. At the Idaho National Engineering Laboratory (INEL),
located in the eastern part of the Snake River Plain, liquid-
waste-disposal practices are constantly monitored, and, as of
1975, only strontium-90 has exceeded the maximum standard
for drinking water (van der Leeden et al., 1975~. The majority
of radionuclides disposed of at INEL have short half-lives and
are of no consequence. Mining is another potential source of
contamination. Large-scale mining goes on for silver, lead,
zinc, sand and gravel, and stone. There are 11 abandoned coal
mines, 1749 abandoned metal mines, and 208 abandoned non-
metal mines. The extensive agricultural industry in Idaho pre-
sents several potential contamination hazards. Fertilizers and
pesticides are used in large quantities. Dieldrin, now banned
but once used heavily for the control of Weiss worm in potatoes,
still persists in the soil. In 1973, there were 563 feedlots mostly
located along the Snake River. There are at least 5000 domestic
and agricultural waste-disposal wells all located in the Snake
River Plain. A few cases of serious contamination from waste-
disposal wells have resulted because of the high permeability
of the aquifer. Of the 29 known incidents, the majority (14 or
48 percent) are due to contamination from human and animal
organic wastes. Industrial and radioactive wastes combined ac-
count for 24 percent of the cases. Of the incidents, 62 percent
actually affected the water supplies and 34 percent threatened
them. Thirty-one percent of the contamination incidents re-
sulted in or posed the threat of outbreaks of disease. The means
of detection was usually by well contamination or by investi-
gation. In 55 percent of the cases no mention was made of any
remedial action that has been taken.
Illinois
In Illinois, groundwater is the freshwater source for approxi-
mately 1600 public water-supply systems and the principal
source for industry, agriculture, and almost all private water-
supply systems in the state (Gibb and O'Hearn, 1980~. The
state used about 1000 mad of groundwater in 1978, which
accounted for about 8 percent of total freshwater use. In 1970,
38 percent of the entire state population and 82 percent of the
rural population were dependent on groundwater as a drinking
source (Piskin et al., 1980~.
~ 7 ~
wright, 1977; Piskin et al., 1980; U.S. Congressional Research
Service, 1980; U.S. EPA, 1981~. Of the known incidents of
groundwater contamination, 44 of them (76 percent) affected
or threatened the water supplies. The most prevalent source
of contamination is from animal and human wastes (20 cases or
34 percent) followed by industrial waste and landfill leachate
(21 and 28 percent, respectively>. Groundwater from shallow
wells often has large concentrations of nitrate. Eighty-one per-
cent of the dug water wells, less than 50 feet deep, contained
in excess of the standard of 10 mg/L of NO3-N2, as opposed to
34 percent of the deeper drilled wells in Washington County
(National Research Council, 1977~. All the incidents involving
contamination from animal or human wastes affected or threat-
ened the water supplies. The majority of incidents (45 or 78
percent) were detected by well contamination, investigation,
and outbreaks of illness. Illinois has a good record for applying
remedial actions, as 66 percent of the incidents have received
some sort of action.
There are no documented cases of groundwater contami-
nation from waste-injection wells, but they are potential haz-
ardous sources of contamination (Ford et al., 1981~. In Illinois,
there are 9 Class I wells (the deepest variety, injecting below
the deepest underground source of drinking water) and 17,167
Class II wells, which are oil- and gas-related, enhanced-recov-
ery, brine-injection, and liquid-hydrocarbon storage wells.
Nebraska
This predominantly agricultural state uses nearly twice as much
groundwater as Florida, 5900 mad or 68 percent of its total
water supply (Lehr, 1981~. Most of this is supplied by the
extensive Ogallala Aquifer, which underlies parts of Texas, New
Mexico, Oklahoma, Kansas, Colorado, Nebraska, Wyoming,
and South Dakota. Of the 35 incidents of contamination from
point sources, 34 percent threatened or affected the water
supplies (Engberg and Spalding, 1978; Spalding et al., 1978a,
1978b, 1979; Exner and Spalding, 1979; Gormley and Spalding,
1979; Junk et al., 1980; Nebraska Department of Environ-
mental Control, 1980a, 1980b, 1981; Spalding and Exner, 1980;
University of Nebraska, 1980; U.S. EPA, 1981~. Incidents in-
volving pesticides and fertilizers accounted for 43 percent of
the cases, but these compounds are also involved in nonpoint-
source contamination. The second most prevalent sources of
contamination are plant, animal, and human wastes, accounting
for 31 percent. Most of the incidents were discovered following
investigation, and in 74 percent of the cases no remedial action
was reported.
Various surveys in Nebraska sampled 4350 wells and found
that 700 contained NO3-N2 contamination in excess of the
standard of 10 mg/L. Studies showed that of the contaminated
wells 575 (82 percent) were contaminated by nonpoint sources
such as nitrogen fertilizer contained in irrigation return flow.
Septic tanks, barnyards and feedlots, and point sources ac-
counted for the remaining 18 percent.
OCR for page 30
30
New Jersey
New Jersey, one of the most densely populated regions in the
United States, has more than 16,000 potable wells (Tucker,
1981~. Sixteen percent of the drinking water is derived from
underground sources. In the southern half of the state, more
than 90 percent of the population receives its drinking supply
from groundwater. In 1976 it was estimated that 406 mad of
groundwater went to public supply, 75 mad to rural supply,
118 mad to industry, and 53 mad to irrigation—a total of 652
mad or 54 percent of the total freshwater supply used in New
Jersey.
In 1981 New Jersey completed an extensive sampling of its
groundwater aquifers for toxic chemical contamination and, in
addition, compiled a comprehensive inventory of groundwater
contamination cases 374 incidents (New Jersey Department
of Environmental Protection, 19817. The aquifer samples for
chemical analysis were collected from a random sampling of
wells throughout the state a sampling, however, designed to
cover all the different areas. Where problems were found,
additional investigations of potential sites of contamination in
the same area were conducted. The contamination inventory
lists all known groundwater pollution in the state but may be
incomplete owing to the occurrence of new cases. The most
numerous incidents are those involving industrial wastes and
petroleum products, which accounted for 40 and 39 percent of
the cases, respectively. Pesticides account for few of the cases,
even though New Jersey is both an industrial and agricultural
state. In 41 percent of the cases some form of remedial action
has been taken; in 48 percent, remedial action is being con-
sidered or a monitoring program has been started.
New Mexico
Groundwater provided 49 percent of New Mexico's water in
1970; 85 percent of the groundwater withdrawals were used
for irrigation (S calf et al., 19737. In 1975, groundwater usage
increased slightly, accounting for 50 percent of the total water
usage or 1600 mad.
Groundwater quality is threatened by overpumping in the
eastern part of the state; mining for uranium, copper, molyb-
denum, and potash in various areas throughout the state; and
oil production in the northeastern and southwestern parts of
the state.
There have been 105 reported incidents of groundwater con-
tamination in New Mexico (New Mexico Environmental Im-
provement Division, 1980; U.S. EPA, 1981~. Most are cases
of chloride contamination from oil-field brines (40 cases). Of
these cases, 36 affected water supplies. Animal and human
wastes accounted for 31 cases, 28 of which resulted in contam-
inated drinking water supplies. Mine wastes also accounted for
14 incidents. Only 6 percent of the total reported incidents
caused adverse public health effects. The majority of incidents
were discovered by contamination of well water. Fewer than
30 percent of the cases of groundwater contamination men-
tioned that any remedial action had been taken.
VERONICA I. PYE and JOCELYN KELLY
South Carolina
In 1970, 61 percent of the total population of South Carolina
relied on groundwater for their drinking water supply (Scarf et
al., 1973), and groundwater accounted for 23 percent of the
total water usage from all sources. Lehr (1975>, however, showed
that in 1975 only 3 percent of the total use was attributable to
groundwater. Total groundwater usage in 1975 was 200 mad.
There are 89 known cases of groundwater contamination (South
Carolina Department of Health and Environmental Control,
1980, 1981~. Petroleum products are involved in the majority
of incidents, 43 cases (48 percent), of which 88 percent affected
the water supply. Contamination by industrial wastes ac-
counted for 28 of the incidents (31 percent), of which half
threatened or affected the water supply. More than half the
cases were detected by well contamination. For the majority
of incidents (89 percent) remedial action was under consider-
ation, monitoring had been started, or no remedial action was
mentioned.
SUMMARY AND CONCLUSIONS
The summaries of groundwater pollution sources completed
by the U.S. EPA (Table 1.1) and the Environmental Assess-
ment Council (EAC) (Table 1.2) show that contamination prob-
lems from several sources have been reported from all parts of
the United States and that the problems vary from one region
to another, depending on climate, population density, intensity
of industrial and agricultural activities, and the hydrogeology
of the region. A comprehensive national survey might well
uncover other important sources of contamination or different
frequencies of the same sources. Neither the U.S. EPA nor
the EAC summaries can be considered complete as they do
not result from comprehensive national surveys. It is difficult
to estimate severity from these summaries as there is no es-
tablished method for doing so. Essentially the information con-
tained in the EAC state summaries presents a"best-case" sce-
nario; the situation can only change as new cases of contamination
are discovered.
The important sources of contamination identified in the
EAC state summaries (Table 1.2) differ somewhat in order of
importance from those identified by the U.S. EPA summaries
(Table 1.1) partly because the EAC summarized information
from individual states whereas the U. S. EPA did regional sum-
maries and because the methods of assessment were different.
The U.S. EPA summaries are empirical assessments relying
on the expertise of professionals who had worked in the regions
studied If. W. Keeley, Kerr Environmental Research Labo-
ratory, personal communication, 19821. Data for the EAC state
summaries were based on anecdotal reports of case histories
supplied by state agencies, and the categories for types of con-
taminants are fewer and broader than those in the U.S. EPA
surveys.
Some generalizations can be made from the combined results
of the two surveys. It is clear that human and sometimes animal
wastes are a high-priority source of contamination throughout
OCR for page 31
The Extent of Groundwater Contamination
31
TABLE 1.2 Most Frequently Reported Sources of Groundwater Contamination in the Ten States Reviewed by the Environmental
Assessment Councila
% For Which
Total Number Remedial
Natural of Known % Affecting Actions
Groundwater Quality of Most Frequently Reported Contamination or Threatening Have Been
Use, mgdb Groundwaterc Sources of Contamination Incidents Water Supply Undertaken
.
Arizona
Connecticut 1 16
4800 Generally good;
mineralization
problems
13400-19000 Good
Good to excellent
Florida 3000 Generally good
Idaho
5600 Good
Illinois 1000 Generally good
Nebraska 5900 Generally good
New Jersey 790 Generally good
New Mexico 1500
South Carolina 200
Fair to good;
mineralization
problems
Suitable for most
uses
1. Industrial wastes
2. Landfill leachate
3. Human and animal wastes
. Saltwater intrusion
2. Nitrates from agricultural
practices
3. Brines and other industrial
and military wastes
1. Industrial wastes
2. Petroleum products
3. Human and animal wastes
1. Chlorides from saltwater
intrusion and agricultural
return flow
2. Industrial wastes
3. Human and animal wastes
1. Human and animal wastes 29 97 45
2. Industrial wastes
3. Radioactive wastes
1. Human and animal wastes 58 76 70
2. Landfill leachate
3. Industrial wastes
1. Irrigation and agriculture
2. Human and animal wastes
3. Industrial wastes
1. Industrial wastes
2. Petroleum products
3. Human and animal wastes
1. Oil-field brines
2. Human and animal wastes
3. Mine wastes
1. Petroleum products
2. Industrial wastes
3. Human and animal wastes
23 100 26
Not known Not known Not known
64 59 30
92 63 39
35 34 26
374 50 41
105 83 29
89 74 45
aPye et al. (1983).
Leer (1981).
Ivan der Leeden et al. (1975), Miller et al. (1974, 1977), Fuhriman and Barton (1971), and Scalf et al. (1973)
the country. In the EAC survey, human and animal wastes are
among the top three contaminants in every state surveyed
except California (for which individual cases were not avail-
able). Human wastes are ranked as highest-priority contami-
nants in three of the regions surveyed by the U.S. EPA
Northeast, Northwest, and Southwest. They are of medium-
high priority in the southeastern and southcentral regions. In-
dustrial wastes are also common and high-priority contaminants
in most regions of the country. In the Northeast, both surveys
show industrial waste disposal as the biggest source of ground-
water contamination. In the southeastern (Florida, South Car-
olina) and northwestern (Idaho) states surveyed by EAC, in-
dustrial wastes are the second most prevalent contaminants of
groundwater, which concurs with the U. S. EPA regional sur-
vey. And in the northcentral states (Illinois, Nebraska), where
agricultural activities are important, industrial wastes are ranked
third in reported frequency of contamination. In the south-
western (Arizona, California) and southcentral (New Mexico)
states, disposal of oil-field brines accounts for a high percentage
of industry-related contamination. Land disposal of general in-
dustrial wastes is of secondary importance.
Beyond industrial wastes and human and animal wastes, the
sources of contamination vary considerably from one region of
the country to another depending on the intensive activities of
a particular state (e.g., mining, agriculture, industry) and the
geographic and geologic location of the state (some coastal states
have severe problems with saltwater intrusion into ground-
water; states located in snowbelts have problems with chloride
OCR for page 32
32
contamination from road salts; states having soluble aquifers
have problems with mineralization). The major sources of con-
tamination are nearly all induced by human activity, apart from
naturally poor quality water caused by dissolution of natural
compounds in the strata through which groundwater flows.
Although contamination of groundwater has occurred
throughout the United States, and is likely to continue to some
extent in the future, we are still in a position to make choices
on how best to use, manage, and protect this valuable resource.
REFERENCES
Arizona Division of Environmental Health Services (1979). Arizona
Surface Impoundment Assessment Ground Water Contamination
Cases, 47 pp.
Braids, O. C. (1981). Behavior of contaminants in the subsurface, in
Seminar on the Fundamentals of Ground Water Quality Protection,
presented by Geraghty and Miller, Inc., and American Ecology
Services, Inc., Cherry Hill, N.J., October 5-6.
California Department of Water Resources (1975). California's ground
water, California Department of Water Resources Bulletin 118.
California State Water Resources Control Board and Regional Water
Quality Control Boards (1980). Water Quality/Water Rights: 1978-
80 Report.
Council on Environmental Quality (1981). Contamination of Ground
Water by Toxic Organic Chemicals, Washington, D.C., 85 pp.
Engberg, R., and R. F. Spalding (1978). Ground water quality atlas
of Nebraska, Resource Atlas No. 3, University of Nebraska Lin-
coln, 39 pp.
Exner, M. E., and R. F. Spalding (1979). Evolution of contaminated
ground water in Holt County, Nebraska, Water Resour. Res. 15,
139-147.
Florida Department of Environmental Regulation (1980). Florida Sur-
face Impoundment Assessment: Final Report, Tallahassee, Fla., 298
PP
Florida Department of Environmental Regulation (1981a). Hazardous
Waste Inventory, Tallahassee, Fla., 59 pp.
Florida Department of Environmental Regulation (1981b). Summary
of Known Cases of Ground Water Contamination in Florida, Tal-
lahassee, Fla., 12 pp.
Ford, M., R. Piskin, M. Hagele, R. Strom, and J. Dickman (1981).
Inventory and Preliminary Assessment of Class I and Class 11 In-
jection Wells in Illinois, State of Illinois Environmental Protection
Agency, Div. of Land/Noise Pollution Control, 111 pp.
Frick, D., and L. Shaffer (undated). Assessment of the availability,
utilization, and contamination of water resources in New Castle County,
Delaware, Department of Public Works, Office of Water and Sewer
Management, New Castle County, Delaware (for U.S. EPA Office
of Solid Waste Management Programs, Contract No. WA-6-99-2061-
J), 215 pp.
Freeze, R. A., and J. A. Cherry (1979). Ground Water, Prentice-Hall,
Inc., Englewood Cliffs, N.J., 604 pp.
Fuhriman, D. K., and J. R. Barton (1971). Ground water pollution in
Arizona, California, Nevada, and Utah (Report #1600ERU for the
Office of Research and Monitoring, U.S. EPA), 249 pp.
Geraghty and Miller, Inc. (1979). Investigations of Ground Water Con-
tamination in South Brunswick Township, N.J., Geraghty and Miller,
Inc., Syosset, N.Y., 49 pp.
Gibb, J. P., and M. O'Hearn (1980). Illinois ground water quality data
summary, prepared by Illinois State Water Survey (for the Illinois
VERONICA I. EYE and JOCELYN KELLY
Environmental Protection Agency, Contract No. 1-47-26-84-353-00),
60 pp.
Gormley, J. R., and R. F. Spalding (1979). Sources and concentrations
of NO3-nitrogen in ground water of the Central Platte region, Ne-
braska, Ground Water 17, 291-300.
Hadeed, S. J. (1979). DBCP Well Sampling Program for Yuma County,
Arizona (7 June-26 July 1979), Arizona Dept. of Health Services,
Phoenix, Ariz., 33 pp.
Handman, E. H., and J. W. gingham (1980) Effects of Selected Sources
of Contamination on Ground Water Quality at Seven Sites in Con-
necticut, U.S. Geol. Surv. Open File Rep. 76-1596, 63 pp.
Handman, E. H., I. G. Grossman, J. W. gingham, and J. L. Rolston
(1979). Major Sources of Ground Water Contamination in Con-
necticut, U.S. Geol. Surv. Open File Rep. 79-1069, 59 pp.
Jackson, R. E., ed. (1980). Aquifer contamination and protection, Proj-
ect 8.3 of the International Hydrological Programme, UNESCO,
Paris, France, 440 pp.
Junk, G. A., R. F. Spalding, and J. J. Richard (1980). Areal, vertical,
and temporal differences in ground water chemistry, II. Organic
constituents, J. Environ. Qual. 9, 479-483.
Keeley, J. W. (1976). Ground water pollution problems in the United
States, in Proceedings of a Water Research Conference, "Ground
Water Quality, Measurement, Prediction and Protection."
Kerns, W. R., ed. (1977). Public policy on ground water protection,
in Proceedings of a National Conference, April 13-16, Virginia Po-
lytechnic Institute and State University, Blacksburg, Va.
Lehr, J. H. (1975). Ground water pollution problems and solutions,
water pollution control in low density areas, in Proceedings of a
Rural Environmental Engineering Conference, W. J. Jewell and R.
Swan, eds., University Press of New England, Hanover, N.H.
Lehr, J. H (1981). Groundwater in the eighties, Water and Engineering
Management 123(3), 30-33.
Lehr, J. H. (1982). How much ground water have we really polluted?
(editorial), Ground Water Monitoring Rev. (Winter), 4-5.
Lemmon, J. (1980). Drums along the Salt, in Proceedings of the Arizona
Section of the American Water Resources Association Symposium
on Water Quality Monitoring and Management, Tucson, Ariz., pp.
7-12.
Lindorff, D. E., and K. Cartwright (1977). Ground water contami-
nation: problems and remedial actions, Environ. Geol. Notes II 81,
Illinois State Geological Survey, 58 pp.
Leopold, L. B. (1974). Water: A Primer, W. H. Freeman, San Fran-
CiSCO, Calif., 172 pp.
Matthess, G. (1982). The Properties of Ground Water, John Wiley,
New York, 406 pp.
Miller, D. W. (1981). Basic elements of ground water contamination,
in Seminar on the Fundamentals of Ground Water Quality Protec-
tion, Geraghty and Miller, Inc., and American Ecology Services,
Inc., Cherry Hill, N.J.
Miller, D. W., F. A. DeLuca, and T. L. Tessier (1974). Ground water
contamination in the northeast states, EPA 660/2-74-056, U.S. EPA,
Office of Research and Development, Washington, D.C., 328 pp.
Miller, J. C., P. S. Hackenberry, and F. A. DeLuca (1977). Ground
water pollution problems in the southeastern United States, EPA
600/3-77-012, U.S. EPA, Office of Research and Development,
Washington, D.C., 361 pp.
National Research Council (1977). Drinking, Water and Health, Vol.
1, Safe Drinking Water Committee, National Academy of Sciences,
Washington, D.C., 939 pp.
Nebraska Department of Environmental Control (1980a). Water Qual-
ity Report [Pursuant to Section 305(b) of the Clean Water Act],
Lincoln, Neb., 303 pp.
Nebraska Department of Environmental Control (1980b). Final Report:
Nebraska Surface Impoundment Assessment, Lincoln, Neb., 72 pp.
OCR for page 33
The Extent of Groundwater Contamination
Nebraska Department of Environmental Control (1981). An Investi-
~,ation of the Causes of Nitrate Contamination in the Ground Water
of the Lower Big Nemaha Drainage Basin, Lincoln, Neb., 8 pp.
New Jersey Department of Environmental Protection (1981). Ground
Water Pollution Index, 1975-June 1981, Trenton, N.J., 55 pp.
New Mexico Environmental Improvement Division (1980). New Mex-
ico Surface Impoundment Assessment, Santa Fe, N. M ., 157 pp.
Piskin, R., L. Kissinger, M. Ford, S. Colantino, and J. Lesnak (1980).
Inventory and Assessment of Surface Impoundments in Illinois, I1-
linois Environmental Protection Agency, Division of Land/Noise
Pollution, 160 pp.
Pye, V. I., R. Patrick, and J. Quarles (1983). Groundwater Contam-
ination in the United States, University of Pennsylvania Press, Phil-
adelphia.
Robertson, F. N. (1975). Hexavalent chromium in the ground water
in Paradise Valley, Arizona, Ground Water 13, 516-527.
Rolston, J. L., I. G. Grossman, R. S. Potterton, and E. H. Handman
(1979). Places in Connecticut where ground water is known to have
deteriorated in quality, U.S. Geol. Surv. Misc. Field Studies Map,
MF-981-b.
Scalf, M. R., J. W. Keeley, and C. J. LaFevers (1973). Ground water
pollution in the south central states, EPA-R2-73-268, U.S. EPA,
Washington, D.C., 181 pp.
Schmidt, K. D. (1972). Ground water contamination in the Cortaro
area, Pima County, Arizona, in Hydrology and Water Resources in
Arizona and the Southwest, American Water Resources Association
and the Hydrology Section of the Arizona Academy of Sciences,
Prescott, Ariz.
South Carolina Department of Health and Environmental Control (1980).
Inventory of Ground Water Contamination Cases in South Carolina,
58 pp.
South Carolina Department of Health and Environmental Control (1981).
Inventory of Known Ground Water Contamination Cases and Gen-
eralized Delineation of Five Ground Water Recharge Areas in South
Carolina, 122 pp.
Spalding, R. F., and M. E. Exner (1980). Areal, vertical and temporal
differences in ground water chemistry, I. Inorganic constitutents, J.
Environ. Qual. 9, 466-479.
Spalding, R. F., J. R. Gormley, B. H. Curtiss, and M. E. Exner
(1978a). Non-point nitrate contamination of ground water in Merrick
County, Nebraska, Ground Water 16, 86-95.
Spalding, R. F., G. A. Junk, and J. J. Richards (1978b). Pesticides in
ground water beneath irrigated farmland in Nebraska, Pesticides
Monitoring J. 14(2), 70-73.
Spalding, R. F., M. E. Exner, J. J. Sullivan, and P. A. Lyon (1979).
Chemical seepage from a tail water recovery pit to adjacent ground
water, J. Environ. Qual. 8, 374-383.
Thomas, H. E., and D. A. Phoenix (1976). Summary appraisals of the
nation's ground water resources California region, in'U.S. Geol.
Surv. Prof. Pap. 813-E.
Tucker, R. K. (1981). Groundwater Quality in New Jersey: An Inves-
tigation of Toxic Contaminants, New Jersey Department of Envi-
33
ronmental Protection, Office of Cancer and Toxic Substances Re-
search.
U.S. Congressional Research Service (1980). Resource Losses from
Surface Water, Ground Water and Atmospheric Contamination: A
Catalog, prepared for U. S. Senate Committee on Environment and
Public Works, Washington, D.C., 246 pp.
U.S. Environmental Protection Agency (1977). Waste disposal prac-
tices and their effects on ground water, Report to Congress, Wash-
ington, D.C., 512 pp.
U.S. Environmental Protection Agency (1978a). Executive summary:
surface impoundments and their effects on ground water in the
United States a preliminary survey, EPA-570/9-78-005, U. S. EPA,
Washington, D.C., 30 pp.
U. S. Environmental Protection Agency (1978b). Surface impound-
ments and their effects on ground water quality in the U.S. a
preliminary survey, EPA/9-78-004, Washington, D.C., 275 pp.
U.S. Environmental Protection Agency (1980a). Ground water pro-
tection, U.S. Environmental Protection Agency Water Quality Man-
ag,ement Report, Washington, D. C., 36 pp.
U.S. Environmental Protection Agency (1980b). Planning Workshops
to Develop Recommendations for a Ground Water Protection Strat-
egy, Appendixes, Washington, D.C., 171 pp.
U.S. Environmental Protection Agency (1981). Computer printout of
disease outbreaks attributed to ground water between 1948 and 1980,
Cincinnati, Ohio.
U.S. General Accounting Office (1978). Waste disposal practices a
threat to health and the nation's water supply, CED-78-120, Wash-
ington, D.C., 34 pp.
U.S. General Accounting Office (1980). Ground water overdrafting
must be controlled, a report to Congress of the United States by the
Comptroller General, CED-80-96, Washington, D.C., 52 pp.
U. S. Water Resources Council (1978a). The Nation's Water Resources,
1975-2000, Second National Water Assessment, Vol. 1: Summary,
86 pp.
U. S. Water Resources Council (1978b). The Nation's Water Resources,
1975-2000, Second National Water Assessment, Vol. 2: Water Quan-
tity, Quality and Related Land Considerations, 618 pp.
U. S. Water Resources Council (1978c). The Nation's Water Resources,
1975-2000, Vol. 3: Analytical Data Survey, 89 pp.
University of Nebraska (1980). Maps of ground water nitrate-nitrogen
concentrations, reconnaissance sampling of the National Uranium
Resource Evaluation program, Nebraska Conservation and Survey
Division, Institute of Agriculture and Natural Resources, Lincoln,
Neb.
van der Leeden, F., L. A. Cerrillo, and D. A. Miller (1975). Ground
water problems in the northwestern United States, U.S. Environ-
mental Protection Agency, Office of Research and Development,
EPA-660/3-75-018, Washington, D. C., 361 pp.
Walker, W. H. (1969). Illinois ground water pollution, J. Am. Water
Well Assoc. 61(1), 31-40.
Weimar, R. A. (1980~. Prevent ground water contamination before it's
too late, Water and Wastes Eng. 30-33, 63.
OCR for page 34
Representative terms from entire chapter:
groundwater contamination
