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                  Environmental Protection
                                  Office of Wa:er
                                  Office of Pestooes anc
                                  Toxic SuDsts.-.ces
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 c/EPA     National  Pesticide  Survey

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     The U.S. Environmental Protection Agency (EPA) has completed rts 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.  Simazine was one of the pesticides
detected in the Survey. This fact sheet provides a description of simazine. its potential
hearth effects, and guidance on both treating and preventing well contamination.

     Simazine is the common name of an herbicide which is a  member of the
chemical ramify of triazines.  Simazine was registered for use in the late 1960s. It has
been sold under the trade names of Aquazine, Princep, Gesatop, Weedex, Drexel
Simazine and the discontinued trade names of Framed and Simadex.  Simazine is also
a component of otner herbicides such as Amizine, Pramitol 5PS, Simazol, Simazat,
and Remtal. Simazine is used to control broadleaf and grass weeds in com, citrus,
deciduous fruits and nuts, olives, pineapple, established alfalfa, and perennial grasses
grown for seed or pasture, turf grasses grown for sod, ornamentals, nursery plantings,
Christmas tree plantations, sugarcane, asparagus, and artichokes.  It is also used as a
nonselective herbicide for vegetation control in non-agricultural land and for selective
control of algae and submerged weeds in ponds. It is approved for algae control in
swimming pools, large aquaria, ornamental fish ponds, fountains, and recirculating
water cooling towers.

     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 teaching, 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
simazine 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.  Simazine has a medium potential to be transported, and
a low potential to be transformed.
NPS Slmuin*

How Does
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      Simazine migration into ground water could result from the presence of sirr.azir.c
in the soil due to agricultural and other applications.  Non-agricultural applications of
simazine include use on golf courses.  Simazine could also reach ground water from
direct entry into a well through accidental chemical spills or improper storage near a

      Based on the results of the NPS, EPA estimates that simazine Is present, at or
above the analytical detection level of 0.38 yg/L used in the Survey, in about 1,080
(1.1%) CWS wells and 25,100 (0.2%) rural domestic wells nationwide.  Considering the
precision of the Survey, EPA estimates that the number of CWS wells could be as low
as 350 or as high as 2,540, whereas the number of rural domestic wells could be as
low as 590  or as high as 141,000.  Simazine is measured in micrograms per liter
(^g/L) which is equivalent to pans per billion (ppb).  Simazine was not detected at
concentrations above EPA's drinking water Lifetime Health Advisory Level (HAL) and
proposed Maximum Contaminant Level (MCL) of 1 .0 ^g/L  Other studies, however,
indicate concentrations above the HAL and MCL

Non-Cancer Effects:  EPA has set a Lifetime Health Advisory Level tor simazine in
drinking water at 1 ^g/L.  EPA believes that water containing simazine at or below this
level is acceptable for drinking every day over the course of one's lifetime, and does
not pose any health concerns. 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.  Consuming simazine, however, at high levels well above
the Lifetime Health Advisory Level over a long period of time has been shown to result
in adverse hearth effects in animal studies, including tremors, damage to the testes,
kidneys, liver, and thyroid, disturbances in sperm production, and gene mutations.

Cancer Ri$k:  EPA currently considers Simazine to be a possible human carcinogen
(cancer-causing agent). EPA estimates that if an individual consumes water
containing simazine at 0.3 ug/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 regulations set achievable levels of drinking water quality  to protect human
health. The proposed MCL for simazine is 1 vg/L (Jury 25, 1990).
      Simazine can be detected in drinking water by a laboratory using an EPA
method such as #507.  If simazine is detected in well water and confirmed by
retesting to be above 1 pg/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
suppliers are required to notify customers if the drinking water that they deliver
contains a contaminant that exceed its MCL

      You may also be able to treat your well water to remove  pesticides and other
contaminants.  Treatment technologies that can  remove simazine from water include
granular and powder activated carbon adsorption.  Other technologies such as ion
exchange, reverse osmosis, ozone oxidation, and ultraviolet irradiation are in the
experimental stages for this pesticide and 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. State or County health officials
should be able to provide advice on the best approach to follow.

How Can
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      Several steps may be taken to prevent pesticides or nitrate from entering weiis,
such as eliminating direct entry through the well wall, drilling a new well, or modifying
or reducing pesticide and fertilizer use.

Eliminate Diract Entry Through tha 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
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 Will

      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 Pastlclda 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 also find that you can 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 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).
                  Survty Datlgn

                  Survay Anatytat

                  Quality Assurance/
                  Quality Control
                            Analytical Met/tods

                            Summary Ratultt

                            Fact Sh*ef for aach
                            defected anaryta
Project Summary


How EPA Will Use
Tha NPS A*sufts
                        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
                                                   Information on regulation of
                                                   pesticides in drinking
NPS S/maz/n*

                  National Pesticide Telecommunications Network
                  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 (NT1S)
                  528S Port Roy«i "oad
                  Springfield,  VA 22161
                  (703) 487-4650
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)
NPS 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.  K 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 Hearth
                  Advisories. April, 1990.

                  U.S* Environmental Protection Agency.  Hearth Advisory Summaries. January 1989.

                  U.S. Environmental Protection Agency.  Pesticides in Drinking Water Wells, September

                  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.
                                                                                       NPS S/mju/ne