United States
Environmental Protection
Agency
Office of Water
Office of Pesticides and
Toxic Substances
Fall 1990
&EPA National
Survey
Ethylene Dibromide (EDB)
H H
I I
H—C—C—H
I I
Br Br
Ethylene Dibromide
(EDB)
What is EDB?
How Does
EDB Behave
in Soil and
Ground
Water?
How Does
EDB Get into
Ground
Water?
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. Ethylene Dibromide (EDB) was one of
the pesticides detected in the Survey. This fact sheet provides a description of EDB,
its potential health effects, and guidance on both treating and preventing well
contamination.
Ethylene dibromide (EDB) is the common name of an insecticide which has
been sold under the discontinued trade names of Soilbrom, Dowfume, Bromofume,
KopFume, and Nephis. EDB was registered for use in 1948, in 1984, EPA canceled all
agricultural uses of the chemical. EDB was an insecticidal fumigant used for
controlling pests in stored products, for the treatment of fruits and vegetables, for spot
treatment of flour mills, and for soil treatment against certain insects and nematodes.
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 soil through adsorption (adherence) to soil
particles and undergo little movement in air or water. Pesticides may be transformed
by reaction with water, microorganisms, and exposure to sunlight. The likelihood that
EDB will migrate into ground water is influenced by its tendency to be transported
(move) from soil to air and water and to be transformed by these various processes,
as well as by the characteristics of the site, such as soil type, moisture, temperature,
and depth to ground water. EDB has a high potential to be transported, and a
medium potential to be transformed.
EDB migration into ground water could result from the underground injection of
EDB as a soil fumigant for agricultural applications. EDB could also reach ground
water from direct entry into a well through accidental chemical spills or improper
storage near a well. In addition, EDB was also used as an additive in leaded gasoline
and may have reached ground water due to leaking gasoline storage tanks.
WPS Ethylene Dibromide (EDB)
Printed on Recycled Paper
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Findings of
the National
Pesticide
Survey
What Health
Effects Might
be Caused by
EDS In
Drinking
Water?
How is Water
Treated to
Remove
Contami-
nants?
How Can
Water
Contamina-
tion be
Prevented?
Based on the results of the NFS, EPA estimates that EDB is present, at or
above the analytical detection level of 0.010 fjg/L used in the Survey, in about 19,200
(0.2%) rural domestic wells nationwide. Considering the precision of the Survey, EPA
estimates that this number could be as low as 160 or as high as 131,000. EDB is
measured in micrograms per liter (/L/g/L) which is equivalent to parts per billion (ppb).
EDB was sometimes detected at concentrations above EPA's proposed Maximum
Contaminant Level (MCL) of 0.05 jug/L EPA notified any well owners and operators
within 24 hours when detections were above the proposed MCL. EDB was not
detected in any CWS wells.
Non-Cancer Effects: A Lifetime Health Advisory Level for EDB in drinking water has
not been established by EPA. Consuming EDB, however, has been shown to result in
adverse health effects in animal studies, including damage to the liver, kidneys, and
testes (including effects on sperm), genetic mutations, and chromosomal damage.
Cancer Risk: EPA considers EDB a probable human carcinogen (cancer-causing
agent) because high doses to laboratory animals over the course of their lifetime
causes cancer. EPA estimates that if an individual consumes water containing EDB at
0.0004 pg/L over his or her entire lifetime, that person would theoretically have no
more than a 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 MCLs.
These regulatory standards set achievable levels of drinking water quality to protect
human health. The proposed MCL for EDB is 0.05 pg/L (May 22, 1989).
EDB can be detected in drinking water by a laboratory using an EPA method
such as #504. If EDB is detected at any level 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. If you receive your well
water from a community water system, and have concerns about the quality of your
well water, contact your State public water supply agency. 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 able to treat your well water to remove pesticides and other
contaminants. Treatment technologies that can remove EDB from water include
aeration, distillation (boiling), and activated carbon adsorption. However, these
treatment techniques are not necessarily appropriate or available in every situation.
Certain treatment methods are more suitable for large community water systems than
for individual domestic wells. Your State or County health officials should be able to
provide advice on the best approach to follow.
Several steps may be taken to prevent pesticides or nitrate from entering wells,
such as eliminating direct entry through the well wall, drilling a new well, or modifying
or reducing pesticide and fertilizer use.
Eliminate Direct Entry Through the Weil Wall
If pesticides or nitrate are present in well water, they may be entering the
ground water through the well itself rather than through the soil. If the well is old or
poorly constructed, or if there are visible cracks in the well casing, obtain expert
advice on whether or not improvements can be made to the well. In addition,
WPS Ethylene Dibromide (EDB)
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Why was the
National
Pesticide
Survey
Conducted?
Where to Go
for More
Information
investigate simple methods of capping the well or sealing it at the surface to prevent
entry. Do not conduct any mixing activities near the well if you use well water to mix
pesticides because a spill could lead to direct contamination of the well,
Drill a New Well
If the soil surrounding the well is the source of contamination, drilling a new or
deeper 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.
Learn More about Pesticide Use
If you use pesticides, whether for agricultural or home lawn and garden
purposes, you should consider attending training courses given by your State or
County agricultural department on how to reduce activities that can contaminate
ground water. You may find that you can eliminate or lessen the frequency or quantity
of your pesticide usage by choosing alternative methods of pest control.
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 NFS 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 Analytes
Quality Assurance/
Quality Control
Analytical Methods
Summary Results
Fact Sheet for each
detected analyte
Project Summary
Glossary
How EPA Will Use
The A/PS Results
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
401 M Street, SW Room NEG004
Washington, DC 20460
(202) 382-3587
Information on regulation of
pesticides in drinking
water
Information on health
effects and safe
handling of pesticides
Background documents
for Survey (available
for review)
NPS Ethylene Dibromide (EDB)
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National Technical Information Service (NTIS)
5285 Port Royal Road
Springfield, VA 22161
(703) 487-4650
Copies of the
NFS Phase I Report
(available 1991)
and
NFS Phase II 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.
Bibliography Meister Publications. Farm Chemicals Handbook. Ohio: Meister 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 1989.
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.
WPS Ethylene Dibromicle (EDB)
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