United States
Environmental Protection
Agency
Emergency and
Remedial Response
(5204G)
9283.1-11
EPA540-K-96-008
PB96-963310
December 1996
EPA Ground Water
Cleanup at
Superf und Sites
6raiy(Pitl2J)
77 West Jackson Boulevard, 12th Floor
Chicago, IL 60604-3590
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GROUND WATER CLEANUP
AT SUPERFUND SITES
Introduction
Over 80 percent of the most serious hazardous waste sites in the U.S. have ad-
versely impacted the quality of nearby ground water (the water present underground
in tiny spaces in rocks and soil). Just as the ground water cleanup process is com-
plex, so are the issues behind the methods and techniques EPA uses to determine
the best approach for each site. This brochure explains some of the approaches EPA
uses to clean up ground water contamination and, most importantly, offers informa-
tion on how citizens can help reduce and prevent ground water contamination.
What is Superfund?
Responding to public concern about abandoned hazardous waste sites across the
nation, Congress passed the Comprehensive Environmental Response, Compensa-
tion, and Liability Act (CERCLA), also known as Superfund. Enacted in 1980,
Superfund directs the U.S. Environmental Protection Agency (EPA) to administer the
Superfund Program in cooperation with state and tribal governments. The program
is designed to:
• Locate, study, and clean up the most serious hazardous waste sites in the
nation (known as Superfund sites)
• Respond to chemical accidents and spills
• Pay for cleanup when parties who own or control a site cannot be found or
cannot afford to pay. (Money for Superfund cleanups comes mostly from taxes
on industries that make hazardous chemicals or petroleum products.)
Protecting and cleaning up contaminated ground water are two of the main concerns
of the Superfund Program. Over 80 percent of Superfund sites have ground water
that is contaminated to some degree.
What is Ground Water?
Ground water is the water present underground in the tiny spaces in rocks and soil.
Underground areas where ground water accumulates in large amounts are called
aquifers. Aquifers are layers of rock or soil that can store and supply enough water to
wells and springs to be economically useful. Most ground water moves slowly —
usually no more than a few feet a day. Ground water in aquifers will eventually
discharge to or be replenished by springs, rivers, wells, precipitation, lakes, wet-
lands, and the oceans as part of the Earth's water cycle.
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Who Uses Ground Water?
Ground water accounts for over 95 percent of the nation's available fresh water
resources, and is the drinking water source for half the people in this country. Many
households, towns, cities, farms, and industries use ground water every day, or
depend on lakes and rivers that receive part of their water supplies from ground
water. Ground water wells near Superfund sites supply public and private drinking
water wells, irrigation, and other agricultural needs, and commercial and industrial
businesses. Ground water quality is very important.
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What is Hazardous Waste?
More than 70,000 chemicals are used regularly around the world. Improper use and
disposal can have harmful effects on humans, plants, and animals. But even when
used properly, many chemicals still have the potential to harm human health and the
environment. When these hazardous substances are thrown away, they can become
hazardous waste. Hazardous wastes are most often a by-product of a manufacturing
process, but there are many sources, including wastes we throw away at home.
Regardless of the source, unless we dispose of hazardous waste properly, it can cre-
ate health risks for people and damage the environment. When hazardous waste is
released into the air, water, or on the land it can spread, contaminating a broad area
and exposing more people to health risks. Proper management and control can greatly
reduce the dangers of hazardous waste. Improper management and disposal of haz-
ardous waste in the past created the hazardous waste sites that are now in the Superfund
program.
How Does Hazardous Waste Affect Ground Water?
Hazardous wastes from a variety of sources have contaminated the ground water at
many Superfund sites. Typically rainfall seeps through the soil, comes in contact with
buried waste or other sources of contamination, picks up chemicals, and carries them
into the ground water. Some pollutants spread quickly, contaminating ground water
several miles from the site.
Polluted ground water may affect drinking water, surface waters, and the people, plants,
and animals near the site. Often the first clue that ground water is contaminated is
when pollutants from a nearby site are found in local drinking water or monitoring
wells. If left unchecked, ground water contamination can continue to spread, increas-
ing the cost of future cleanup, reducing useful water resources, and potentially affect-
ing more people.
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Contaminated Ground Water
Bedrock
What Does Superfund Do About Contaminated Ground
Water?
The Superfund Program strives to restore ground water to beneficial use and pre-
vent any further human exposure to contaminants. This is done by removing or
containing the source of the contamination and cleaning up the affected ground
water. Since many aquifers are a current or potential source of drinking water, most
Superfund site cleanups try to ensure that ground water quality meets federal and
state drinking water standards.
Experience has shown that this cleanup process can take anywhere from several
years to many decades, depending on the conditions at the site. Sometimes, how-
ever, depending on the type of contamination, the ground water cannot be restored.
When this happens, the ground water is prevented from moving to uncontaminated
areas. At every site, the Superfund Program acts to protect human health and the
environment from the effects of hazardous waste contamination.
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Why Can Ground Water Cleanup Take So Long?
Once ground water is contaminated, making it clean enough to drink can be extremely
difficult for several reasons:
• Aquifers are complex structures. Aquifers can contain cracked and
fractured rocks and other geological variations. These variations can act
as nooks and crannies that hold contaminants or create additional path-
ways for contaminants to follow. This makes removing contaminants
difficult.
• Not all contaminants behave in the same way. Different contaminants
behave differently in ground water. This makes them hard to locate and
remove, complicating cleanup. Some do not mix with or dissolve readily
in water. Some are heavier than water and sink to the bottom of an
aquifer, such as dry-cleaning solvents. Other contaminants are lighter
than water and float on top, such as petroleum products like jet fuel and
gasoline.
• Locating the contamination can be difficult. The ability of technology
to find contaminants in ground water is limited. Samples from ground
water wells do not always provide enough information about the extent of
ground water contamination. Other devices for detecting contaminants
and identifying variations in the underground rock and soil can also help,
but only to a certain degree.
• Technology has limitations. Treatment technologies are limited in their
ability to clean up an aquifer, even if the location of the contaminants is
known. Frequently, ground water is cleaned by pumping it to the surface
for treatment. After contaminants have been removed, the water is dis-
charged back into the ground or to a stream or river. Even then, some
contamination remains in the aquifer, which can continue to contaminate
the ground water. Contaminants that cannot be pumped to the surface
with the water must be treated underground, making cleanup more diffi-
cult, expensive, and time consuming.
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What We Have Learned About Ground Water Cleanup
Ground water treatment systems are in place and working well at hundreds of
Superfund sites. The diagram below shows a common ground water cleanup tech-
nology called "pump-and-treat." Here, wells are installed to pump contaminated
ground water to the surface for treatment. As contaminants are removed, the clean
ground water is discharged back into the ground or to a stream or river. Sometimes
pump-and-treat is used with other methods to remove contaminants. These tech-
nologies generally prevent contaminants from spreading beyond the site.
Due to the complexity of aquifers and the types of contamination, not all ground
water can be restored to a safe drinking quality. In particular, contamination by
common solvents and oily waste pose a common, major hurdle for Superfund ground
water cleanups. In such cases, current strategies rely on reducing and containing
ground water contamination. As we gain a better understanding of site characteris-
tics and the nature of ground water contamination, we can clean up more ground
water to meet drinking water standards and contain only the most difficult problems.
Pumping and Treating Contaminated Ground Water
Extract
Contaminated
Water
Aquifer
Bedrock
Reinject
Clean
Water
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Despite the challenges, ground water has been and is being restored for beneficial
uses, including drinking water. Advances in scientific and technical knowledge have
made ground water cleanup faster and more effective. For example:
Progress has been made in techniques used to study Superfund sites.
This includes the development of new sampling and testing devices that
make studies of ground water faster and cheaper. A thorough study is
important in determining the extent of contamination, and in designing the
plan for how a site will be cleaned up.
Knowledge of how contaminants move in ground water has advanced,
helping to predict where contamination might move and who might be
exposed. This knowledge is crucial in designing the cleanup.
There is better understanding of the limits of available cleanup technolo-
gies. For example, it is now easier to predict which portions of an aquifer
can be cleaned up to drinking water standards using pump-and-treat tech-
nology, and which portions must be contained or addressed by another
treatment method.
In some cases, microscopic organisms that live underground can digest
or break down harmful contaminants into harmless elements. This pro-
cess is called "bioremediation." By adding nutrients or oxygen, this pro-
cess can be enhanced and used to clean up contaminated ground water.
Bioremediation relies mostly on nature, involves minimal construction or
disturbance, and is comparatively inexpensive. It has been studied at
many Superfund sites and is formally a part of the cleanup remedy at
some sites.
Use of soaps, solutions, steam, and hot water to remove contaminants
from aquifers has improved. These and other innovative technologies
can increase the effectiveness of a pump-and-treat cleanup.
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WHAT YOU CAN DO!
There are many things you can do to gain a basic understanding of ground water as
a resource and to support efforts to protect ground water quality in your community.
Prevent Ground Water Contamination
The difficulty and costs of cleanups are proof that every effort should be made to
prevent ground water from becoming contaminated. Here are some steps you can
take to protect your ground water.
Ask public works personnel in your local government for information on how to
handle and reduce the use of household chemicals. Investigate whether there is a
program in your area to collect household hazardous wastes, such as solvents,
used paint cans, used motor oil, and pesticides and fertilizers. These programs are
helping to prevent the chemicals we use in our homes from getting into our ground
water! For more information about household hazardous waste, call EPA's RCRA/
UST, Superfund, & EPCRA Hotline at (800) 424-9346.
Report spills, suspicious dumping, or other signs of contamination to your local
health board, state environmental department, or EPA Regional Office. Accidents,
spills and other releases can also be reported to the National Response Center
Hotline at (800) 424-8802.
Keep Informed
Citizens can get information about ground water in their communities by contacting:
• Local water authority or other local natural resource authorities
• Service agencies, such as the County Cooperative Extension Service, and the
Soil and Water Conservation District
• Civic and environmental organizations
• Universities and colleges
• Trade associations of environmental engineers or well drillers.
The local telephone directory or elected officials can help you find information on:
• Where your community gets its drinking water and what state, tribal, or local
efforts are being made to protect water quality
• What possible sources of ground water contamination are in your area and
what government or community programs are in place to monitor these
sources
• Whether your community's water well has been tested in the past year
• Where your solid waste goes, and how ground water is protected there.
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For information about releases of toxic chemicals in your area, call the RCRA/UST,
Superfund, & EPCRA Hotline at (800)424-9346.
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Get Involved
Ask and read about any Superfund sites or other hazardous waste sites in your area.
Attend public meetings, and offer any information you have regarding the history, natural
features, or community activity related to the site. Participate in community work
groups about the site, and give your comments and concerns to state and federal
government staff. Local groups may apply for an EPA Technical Assistance Grant
(TAG) to get independent expert advice on cleanup plans at Superfund sites. In addi-
tion, state and local governments often seek input from citizens and community groups
when developing plans for managing ground water resources.
For further information about the Superfund Program, call EPA's RCRA/UST, Superfund
& EPCRA Hotline at (800)424-9346. To speak to the EPA Community Involvement
Coordinator or a ground water specialist in your EPA Regional Office, contact:
EPA Regional Offices
Beotan
Region 1
Region 2
Region 3
Region 4
Region 5
(617) 565-3420
(212) 637-3000
(215) 566-5000
(404) 562-8357
(312) 353-2000
Region 6 (214) 665-6444
Region 7 (913)551-7000
Region 8 (303) 312-6312
Region 9 (415)744-1305
Region 10 (206) 553-1200
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GROUND WATER is A VITAL RESOURCE
As of 1990, over half of the people in the United States get
their drinking water from ground water (more than 140 mil-
lion people).
Across the country, 95% of rural households and 35% of
urban households use ground water as their drinking water
source.
In the United States, 34 of the largest 100 cities rely com-
pletely or partially on ground water as their source of water.
New Mexico, Mississippi, and Florida rely on ground water
for 90% or more of their drinking water supply.
From 1970 to 1990, seven states or territories more than
doubled their use of ground water for public water supply:
Alaska, Arizona, California, Florida, Kentucky, Missouri, and
Puerto Rico.
More than one-third of the water used in agriculture is
ground water. In Arkansas, Nebraska, Colorado, and Kan-
sas, more than 90% of ground water withdrawals are for
agricultural activities.
As many as 91% of Superfund sites have one or more oper-
able wells within a one-mile radius.
Contamination from Superfund sites has already shut down
supply wells in 344 communities.
There is a threat of ground water contamination at 500 other
Superfund sites where wells are located nearby, but are as
yet unaffected.
Contaminated ground water at Superfund sites discharges
into other water resources: 62% to surface water, 38% to
drinking water aquifers, and 19% to ecologically sensitive
areas.
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Printed on recycled paper
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