United States
Environmental Protection
Agency
Office of Water
Office of Pesticides and
Toxic Substances
Fall 1990
National Pesticide Survey
Chlordane
What Is
Cn/ordane?
How Does
Chlordane
Bertave In
Soil and
Ground
Water?
HotvDoet
C/i/ordane
Get into
Ground
Water?
ct
a
Chtordan*
(alpha toemcr)
The U.S. Environmental Protection Agency (EPA) has completed its five-year
National Survey of Pesticides in Drinking Water Wells (NPS), a study of the presence
of 127 pesticides, pesticide degradates, and nitrate in community water system (CWS)
wells and rural domestic drinking water wells. EPA analyzed for the two most
persistent isomers of chlordane - alpha and gamma chlordane. Isomers are
compounds that have the same molecular composition but different spatial
arrangements. This fact sheet provides a description of chlordane, its potential health
effects, and guidance on both treating and preventing well contamination.
Chlordane (Chlordan) is the common name of an insecticide which is a member
of the chemical family of chlorinated cydodienes. Chlordane was registered in 1948.
It has been sold under the trade name of Gold Crest C-100. Chlordane is no longer
distributed in the United States, but is still registered. Chlordane is used to control fire
ants around underground cables. Chlordane was formeny used to control termites in
homes and to control other insects such as ants, cutworms, and grasshoppers on a
variety of food crops.
The behavior of a pesticide after it is released to the environment is dependent
upon its movement in air, water, and soil as well as the rate at which it is transformed,
or broken down. Pesticides applied to crops or the soil surface may volatilize
(vaporize) to the atmosphere, be carried off by surface runoff, be carried to ground
water through leaching, or remain in the soi through adsorption (adherence) to soil
particles and undergo Uttie movement In air or water. Pesticides may be transformed
by reaction with water, microorganisms, and exposure to sunlight The likelihood that
cMortane wfl migrate into ground water is influenced by its tendency to be
tnneported (move) from soil to air and water and to be transformed by these various
procauaa. at wel at by the characteristics of the site, such as toil type, moisture.
temperature, and depth to ground water. Chlordane has a low potential to be
transported, and a low potential to be transformed.
Chlordane migration into ground water could ratut from the presence of
chlordane in the tofl due to agricultural and other applications of chlordane, such as
underground injection to control termites, on cropped and non-cropped land.
Chlordane could aJto reach ground water from direct entry into a wed through
accidental chemical tp«t or improper storage nearaweL
MPSCMordin*
-------
Findings of
the National
Pesticide
Survey
What Heart/}
Effects Might
be Caused by
Chlordane in
Drinking
Water?
How is Water
Treated to
Remove
Contami-
nants?
How Can
Water
Contamina-
tion be
Prevented?
Chlordane was not found in any official samples from CWS wells or rural
domestic drinking water wells at or above analytical detection levels used in the
Survey by EPA's contract laboratory. Chlordane was, however, detected by EPA's
quality assurance laboratory at much lower levels than the detection limit established
by the contract laboratory. Because EPA's quality assurance laboratory did not
analyze water samples collected from all wells, the results do not represent a
statistically valid sample of wells in the nation. A national estimate of CWS wells and
rural domestic wells containing Chlordane consequently cannot be prepared.
Non-Cancer Effects: A Lifetime Health Advisory Level for Chlordane in drinking water
has not been established by EPA. However, animal studies have indicated consuming
Chlordane results in liver damage and affects the central nervous system.
Cancer Risk: Chlordane is considered by EPA to be a probable human carcinogen
(cancer-causing agent). Chlordane causes cancer in laboratory animals that are given
high doses of the pesticide over the course of their lifetimes. EPA estimates that if an
individual consumes water containing Chlordane at 0.03 fjg/L over his or her entire
lifetime, that person would theoretically have about one-in-a million chance of
developing cancer as a direct result of drinking water containing this pesticide.
Standard: EPA sets enforceable standards for public water systems, called Maximum
Contaminant Levels (MCLs). These regulatory standards set achievable levels of
drinking water quality to protect human health. The proposed MCL for Chlordane is
2 pg/L (proposed as of May 22,1989).
Chlordane can be detected in drinking water by a laboratory using an EPA
method such as #508. If Chlordane is detected in well water and confirmed by
retesting, State or County health officials should be consulted. They may advise
periodic retesting to get an accurate overall picture of the water quality because
changes in seasonal precipitation and changes in pesticide use can cause variations
in the amount of chemicals found in water wells. They also may advise using an
alternative drinking water supply (bottled water is an example of a temporary
alternative), treating the water, or drilling a new or deeper well. Public water suppliers
are required to notify customers if the drinking water that they deliver contains a
contaminant that exceeds its MCL
You may also be abte to treat your well water to remove pesticides and other
contaminants. Treatment technologies that can remove Chlordane from water include
granular and powder activated carbon adsorption and possibly aeration. However,
these treatment technologies are not necessarily appropriate or available for every
situation. Certain treatment methods are more suitable for large community water
systems than tor individual domestic wells. State or County health officials should be
able to provide advice on the best approach to foHow.
Several steps may be taken to prevent pesticides or nitrate from entering wetts.
such as eliminating direct entry through the well wail or drilling a new wen.
Effmfnafe Dinct Entry Through (fie IVeff W*H
If pesticides or nitrate are present in wed water, they may be entering the
ground water through the well itself rather than through the soi. If the well is old or
poorly constructed, or tf there are visible cracks in the well casing, obtain expert
advice on whether or not improvements can be made to the wefl. In addition.
investigate simple methods of capping the wed or sealing it at the surface to prevent
entry.
NPS CMorcton*
-------
Why was the
National
Pesticide
Survey
Conducted?
Where to Go
for More
Information
Drill« New Will
If the soil surrounding the well is the source of contamination, drilling a new or
deeoer well may make sense if water can be drawn from a deeper, uncontaminated
aquifer. Unfortunately, it often is difficult to know the quality of the ground water
without drilling or extensive testing. Seek expert advice before you drill.
EPA conducted this Survey to determine the frequency and concentration of
pesticides, pesticide degradates, and nitrate in drinking water wells nationwide and to
examine the relationship between the presence of pesticides in drinking water wells
and patterns of pesticide use and ground-water vulnerability. The Survey sampled
566 community water system wells and 783 rural domestic wells for 127 pesticides,
pesticide degradates, and nitrate. The wells were selected as a representative
statistical sample to provide nationwide estimates of the presence of pesticides and
nitrate in drinking water wells, and are not meant to provide an assessment of
pesticide contamination at the local, County, or State level.
This fact sheet is part of a series of NPS outreach materials, fact sheets and
reports. The following additional fact sheets are available through EPA's Public
Information Center (401 M Street SW, Washington, DC 20460, (202) 382-2080):
Survey Design
Survey Anar/fes
Quality Assurance/
Qua/rry Control
An«/yt/c«/ Methods
Summery flesuft*
Fact Sneet for each
detected «ne/yte
Project Summery
G/osMry
How EPA Will Use
The NPS Aesufts
Additional information on the Survey and on pesticides in general can be
obtained from the following sources:
U.S. EPA Safe Drinking Water Hotline
1-800-426-4791 (In Washington. DC (202) 382-5533)
Monday-Friday, 8:30 am to 4:30 pm Eastern Time
National Pesticide Telecommunications Network
1-800-858-7378
24 hours a day
U.S. EPA Office of Pesticide Programs (OPP) Docket
Public Information Branch (H7506C)
401 M Street, SW
Washington, DC 20460
Telephone: (703) 557-2805
National Technical Information Service (NTJS)
5285 Port Royal Road
Springfield, VA 22161
(703) 487-4650
Information on regulation
of pesticides in drinking
water
Information on health
effects and safe
handling of pesticides
Background documents
for Survey (available
for review)
Copies of the
NPS Phase I Report
(available 1991)
and
NPS Phase H Report
(when available)
If you are concerned about the presence of pesticides and nitrate in your
private water well, contact your local or State health department Other experts in
your State environmental agency or agriculture and health departments may also be
helpful to you. If you receive your drinking water from a community water system and
have questions about your water quality, contact your local community water system
owner/operator or the State water supply agency.
NPS Ch/ortfene
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Bibliography Meister Publications. Farm Chemicals Handbook. Ohio: Metster Publications. 1990.
U.S. Environmental Protection Agency. Drinking Water Health Advisory: Pesticides.
Michigan: Lewis Publishers, 1989.
U.S. Environmental Protection Agency. Drinking Water Regulations and Health
Advisories. April, 1990.
U.S. Environmental Protection Agency. Health Advisory Summaries. January 1969.
U.S. Environmental Protection Agency. Pesticides in Drinking Water Wells. September
1989.
Worthing, Charles R., ed. The Pesticide Manual. 8th ed. Thornton Heath: The British
Crop Protection Council, 1987.
NPS Chlordtm
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