United States
Environmental Protection
Agency
Office of Water
Office of Pesticides and
Toxic Substances
Fall 1990
vvEPA National Pesticide Survey
Dinoseb
CH—CH2—CH3
Dinoseb
What is
Dinoseb?
How Does
Dinoseb
Behave in
Soil and
Ground
Water?
How Does
Dinoseb 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. Dinoseb was one of the pesticides
detected in the Survey. This fact sheet provides a description of dinoseb, its potential
health effects, and guidance on both treating and preventing well contamination.
Dinoseb (DNBP, Dinitro) is the common name of an herbicide which is a
member of the chemical family of dinitrophenols. Dinoseb was registered for use in
1948. It has been sold under the discontinued trade names of Premerge, Aretit, Ivosit,
Dynamyte, and Dinitro Weed Killer. Dinoseb is also a component of the discontinued
herbicide Premerge Plus. Dinoseb also has fungicidal and insecticidal properties. In
1986, EPA suspended the commercial use of Dinoseb. Dinoseb was used on
agricultural land to control seedling weeds and grasses. Dinoseb was also used in
fruit and nut orchards, grape vineyards, and mint, small grain, soybean, squash,
strawberry, bean, potato, corn, cotton, pea, pumpkin, certain forage crops, and for
controlling perennial weeds and grasses.
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
dinoseb 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. Dinoseb has a medium potential to be transported, and a
high potential to be transformed.
Dinoseb migration into ground water could result from the presence of dinoseb
in the soil due to agricultural applications of dinoseb on agricultural land. Dinoseb
could also reach ground water from direct entry into a well through accidental
chemical spills or improper storage near a well.
WPS Dinoseb
Printed on Recycled Paper
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Findings of
the National
Pesticide
Survey
What Health
Effects Might
be Caused by
Dinoseb 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 dinoseb is present, at or
above the analytical detection level of 1.3 /ug/L used in the Survey, in about 25 (0.03%)
CWS wells nationwide. Considering the precision of the Survey, EPA estimates that
this number could be as high as 870. Dinoseb is measured in micrograms per liter
(jjg/L) which is equivalent to parts per billion (ppb). Dinoseb was not detected at
concentrations above EPA's proposed Maximum Contaminant Level (MCL) and
drinking water Lifetime Health Advisory Level (HAL) of 7 pg/L. Dinoseb was not
detected in any rural domestic wells.
Non-Cancer Effects: Lifetime HALs are based on health effects that were found in
animals given high doses of the pesticides in laboratory studies. This level includes a
margin of safety. EPA has set a Lifetime Health Advisory Level for dinoseb in drinking
water at 7 /jg/L This level includes a margin of safety to protect human health and
should be regarded as a guideline. EPA believes that water containing dinoseb at or
below this level is acceptable for drinking every day over the course of one's lifetime,
and does not pose health concerns. Consuming dinoseb, however, at high levels well
above the Lifetime Health Advisory Level over a long period of time has been shown to
result in adverse health effects in animal studies, including changes in liver and thyroid
weights, reduced fertility, decreased sperm count, increased incidence of abnormal
sperm, reduced fetal weight and survival, and birth defects.
Cancer Risk: Data from laboratory studies are inadequate for EPA to determine if
dinoseb can increase the risk of cancer in humans.
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 dinoseb is 7 jug/L (proposed as of July 25,
1990).
Dinoseb can be detected in drinking water by a laboratory using an EPA
method such as #515.1. If dinoseb is detected in well water and confirmed by
retesting to be above 7 /jg/L, 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
systems 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 dinoseb from water include
activated carbon adsorption and ion exchange. However, these techniques are not
necessarily appropriate or available in every situation. 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 Well 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,
investigate simple methods of capping the well or sealing it at the surface to prevent
WPS Dinoseb
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Why was the
National
Pesticide
Survey
Conducted?
Where to Go
for More
Information
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 agriculture 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 NPS 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)
WPS Dinoseb
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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.
Weed Science Society of America. Herbicide Handbook of the Weed Science Society
of America. 5th ed. Illinois: Weed Science Society of America, 1983.
Worthing, Charles R., ed. The Pesticide Manual. 8th ed. Thornton Heath: The British
Crop Protection Council, 1987.
WPS Dinoseb
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