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v>EPA Pesticide
Fact Sheet
Name of Chemical:
Reason for Issuance:
Date Issued: June 30/1985
Fact Sheet Number: 55
}. Description of the chemical:
Generic name: 2(ethylthlo)-4,6-bls(isopropylaralno)-s-trlazlne ,
Bnplnlcal formula: Cji^iN^S
Common name: Dipropetryn
Trade name: Sancap', Cototar* and GS-16068.
Chemical Abstracts Service (CAS) Registry number: 4147-51-7
Office of Pesticides Program's EPA Chemical Code Number:
104U01
Year of Initial registration: 1973
Pesticide type: Herbicide
Chemical family: S-trlazlne
U.S. producer: Clba-Gelgy Corporation
2. Use patterns and formulations;
Application sites: Dipropetryn Is registered for preemergence
control of pigweed and Russian thistle on cotton. In addi-
tion, dlpropetryn Is registered for use only on cotton
grown on the sandy soils In Oklahoma, Texas, Arizona and
New Mexico.
Type of formulation: Dipropetryn Is available In a wettable
powder formulation.
Types and methods of applications: Dipropetryn can be banded
or broadcast applied to the soil surface with ground equip-
ment or broadcast applied with aerial equipment as a
preeroergence spray.
Application rates: 1.2 to 2.0 Ibs a.l./A on crop sites.
Usual carriers: Water.
3. Science Findings:
Summary science statements:
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Dipropetryn is not acutely toxic by the oral-, dermal, and
eye irritation routes of exposure. The available data are
Insufficient to show that any of the risk criteria listed
in S 162.11(a) of Title 4O of the U.S.Code of Federal
Regulations have been met or exceeded for the uses of
dipropetryn at the present time. There are no valid
chronic toxicity and mutagenicity studies for dipropetryn.
There are also extensive residue chemistry and environmental
fate data gaps.
Available data Indicate that dipropetryn is slightly toxic
to birds and moderately toxic to fish and freshwater inverte-
brates. A detailed ecological hazard assessment cannot be
made until certain environmental chemistry data requirements
are fulfilled.
Chemical characteristics:
Dipropetryn is a solid at room temperature. Its molecular
weight is 255.1 0. The melting point is i0i4—i06°C. Dipro—
petryn is soluble in water ( at 20°C) to 16.0 ppm and
soluble in aromatic and chlorinated hydrocarbon solvents.
Toxicological characteristics:
Acute toxicity effects of dipropetryn are as follows:
Acute Oral Toxicity In rats: >2,197 mg/kg body weight,
Toxicity Category III
Acute Dermal Toxicity In rabbits: >10,000 mg/kg body
weight, Toxicity Category IV
Acute Inhalation Toxicity in rats: >320 mg/i (Il hour
exposure) Toxicity Category IV
Skin irritation in rabbits: Not an Irritant, Toxicity
Category IV
Eye irritation in rabbits: Not an irritant, Toxicity
Category IV.
Subacute toxicity effects on dipropetryn are as follows:
A 19—week rat feeding study and a 1Z —week dog feeding
study indicated effects on various organs at 1200 ppm
dosage (the Lowest Effect Level). The No Observable
Effect Level is i00 ppm.
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Chronic toxicological effects of dipropetryrT have not been
evaluated because there are no valid chronic toxicity
studies in both the rat and dog, oncogenicity studies
in both the rat and mouse, teratogenicity studies in
both the rat and rabbit, a two-generation reproduction
study in the rat; a general rat metabolism study; and
no mutagenicity tests (gene mutation in bacteria, gene
mutation in mammalian cells in culture, chromosomal
aberration analysis in mammalian cells in culture, or
DNA damage in mammalian cells in culture).
Major routes of human exposure:
Non—dietary exposure to dipropetryn by a farmer as an
applicator during mixing, loading, spraying and flagging
Is possible.
Physiological and biochemical behavioral characteristics:
Absorption characteristics: Dipropetryn appears to penetrate
foliage rapidly, minimizing removal from foliage by rain.
Translocatlon: Readily translocated through the xylem from
roots and foliage, accumulating in the apical meristerns
and leaf tips.
Mechanism of’ pesticidal action: Dipropetryn inhibits photo-
lysis of water in the photosynthetic process.
Metabolism in plants: In cotton, dipropetryn’s total resi-
dues are evenly distributed in the seed with crude oil
extracts containing less than the intact seed.
Environmental characteristics:
Adsorption and leaching in basic soil types: Dipropetryn
is more readily adsorbed on soils with high clay and
organic matter content. Dipropetryn and other alkylthio-
s—triazines are adsorbed to a greater extent than most
other commercial triazines.
Microbial breakdown: Soil microorganisms do appear to
play a significant role In degradation of dipropetryn.
Loss from photodecompositlon and/or volatilization: Slight
losses.
Average persistence at recommended rates: When used at re-
commended rates under normal environmental conditions,
dipropetryn’s residual activity is from 1 to 3 months.
Ecological characteristics:
Avian acute oral toxicity: >1,000 mg/kg.
96—hour fish toxicity): 3.130 ppm for bluegill sunfish
(moderately toxic), and 2.1 130 ppm for rainbow trout
(moderately toxic).
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Potential problem for endangered species:
The Agency has evaluated dipropetryn under the cotton
cluster/use patterns. Available data show a low order of
dipropetryn toxicity suggesting that the potential hazard
to endangered species is low.
Currently, there are no identifiable endangered plants
that would be affected by dipropetryn.
The Agency believes that the conventional labeling for
dipropetryn is adequate to properly inform the users on
how to protect any endangered species.
Tolerance assessments:
Data are not available for calculating the Acceptable Daily
Intake (ADI) for dipropetryn. -
The Agency is unable to complete a full tolerance reassessment
because the available dipropetryn toxicology and residue data
do not fully support the established tolerance listed below.
The metabolism of dipropetryn in animals and plants Is not fully
understood. Therefore, the Agency is requiring data on the meta-
bolism of dipropetryn and related metabolite(s) in crops and
animals. Additional long term rodent and nonroderit toxicological
studies are also required. The additional data will be used to
assess dietary exposure to dipropetryn and may lead to revisions
In the existing tolerance. The Agency will not grant any signi-
ficant pending or new tolerances for dipropetryn until the data
are submitted.
Commodities Parts per million
Cottonseeds 0.1
International Tolerances
Presently, there are no tolerances for residues of dipropetryn
in Canada, Mexico, or in the Codex Alimentarlus .
Problems known to have occurred with use:
The Pesticide Incident Monitoring System (PIMS) does not
Indicate any Incident involving agricultural uses of
dipropetryn.
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1• Summary of regulatory position and rationale :
Based on the review and evaluation of all available data and
other relevant information on dipropetryn the Agency has
made the following determinations:
The available data are insufficient to show that any of
the risk criteria listed in § 162.11(a) of Title 1 0 of the
U.S.Code of Federal Regulations have been met or exceeded
for the uses of dipropetryn at the present time.
The Agency has concerns about dipropetryn’s lack of chronic
toxicity data and Its use on a food and feed crop when it
Is structurally related to certain other s—triazlne pesti—
cideb vihich are known to be potential ground water contami-
nants and to cyanazine, a s—triazine pesticide that may be
regulated as a teratogen.
The Agency will not allow any significant new uses to be
established for dipropetryn until the toxicological, resi-
due chemistry, and ground water data deficiencies identi-
fied in the registration standard have been satisfied.
The Agency is imposing restrictions on rotational crops.
The extent of the restrictions will be reconsidered when
additional data are received.
Specific label precautionary statements:
Hazard Information
The human precautionary statements must appear on all
manufacturing—use products (MPs) labels as presribed in
1 0 CFR 162.10.
Environmental Hazard Statements
All MPs Intended for formulation into end-use products
(EPs) must bear the following statements:
“This pesticide is toxic to fish. Do not discharge
effluent containing this product directly into lakes,
streams, ponds, estuaries, oceans or public water8 un-
less this product Is specifically Identified and ad-
dressed in a National Pollutant Discharge Elimination
System (NPDES) permit. Do not discharge effluent con-
taining this product into sewer systems without pre-
viously not1fyir g the sewage treatment plant authority.
For guidance, contact your State Water Board or Regional
Office of the Environmental Protection Agency”.
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“Do not apply directly to water. Do not contaminate
water by cleaning of equipment or disposal of wastes.
In case of spills, cover or incorporate spills.”
Restrictions on Rotational Crops
“Do not plant food and feed crops in dipropetryn—treated
fields unless dipropetryn Is authorized for use on those
crops”.
5. Summary of major data gaps and due dates :
The following toxicological studies are recjuire :
A 90—day inhalation study (October 30, 1986),
Chronic toxicity studies and oncogenicity studies
(September 30, 1989),
Teratology studies (October 30, 1986),
A two generation reproduction study (October 30, 1988),
Mutagenicity data (April-July 1986), and
A general metabolism study (July 30, 1987).
The following environmental fate data are required:
A hydrolysis study (April 30, 1986),
Photodegradation studies in water and on soil (April
30, 1986),
Metabolism tests in aerobic soil and in anaerobic soil
(October 30, 1986),
A mobility test involving leaching and adsorption/desorp-
tion (July 30, 1986),
Accumulation studies on rotational crops (confined:
October 30, 1988 and field: September 30, 1989), and
An accumulation study in fIsh (July 30, 1986).
The following ecological effects data are required:
Two subacute dietary studies (AprIl 30, 1986), and
An acute freshwater invertebrate toxicity study (April
30, 1986).
Product chemistry data are required during 1986.
The following residue chemistry data are required:
Additional plant metabolism data ( July 30, 1987), and
Metabolism studies utilizing ruminants and chickens
(January 30, 1987).
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6. Contact Person at EPA :
Robert J.Taylor (703) 557—1800
Office of Pesticide Programs, EPA,
Registration Division (TS—767C)
Fungicide—Herbicide Branch
401 M Street., S.W.
Washington, DC 20460.
Telephone (703) 557—1800
DISCLAIMER: The Information presented in this Chemical Information
Fact Sheet 18 for Informational purposes only and may not be used
to fulfill data requirements for_pest .cide registration and
reregistration.
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