United States
Environment*! Protection
Agency
Office of Pesticides and Toxic Substances
Office of Pesticide Programs (TS-766C)
Washington. DC 20460
vvEPA
Pesticide
Fact Sheet
Name of Chemical:
Reason for Issuance: Registration Standard
Date Issued: June 24, 198?
Fact Sheet Number: 135
1. Description of Chemical
The following chemical is covered by this pesticide fact sheet:
Common name: Diphenamid
Chemical name: N,N-dimethyldiphenylacetamide
CAS Number: 957-51-7
OPP (Shaughnessy) Number: 036601
Empirical Formula: CjgHjyNO
Direnamid, Dymid, Enide®,
A-831010, L-34-314
Acetamide
Herbicide
Trade Names:
Chemical Family:
Pesticide Type:
Year of Initial
Registration:
Registrants of Technical
Products:
1964
Nor-AM Chemical Co.
2. Use Patterns And Formulations
Application Sites:
Methods of Application:
Application Rates:
Types of Formulations:
Field, bush, vine, vegetable crops,
fruit, citrus fruit, cotton, ornamental
plants, forestry and turf.
Primarily applied as broadcast or
banded spray by ground or aerial
equipment.
Terrestrial food crops: 2.0 to 9.0 lb. ,
active ingredient (ai)/acre,
Terrestrial non-food crops: 2.0 to 6.0
lb., ai/acre,
Ornamentals and forest trees 0.50 to
1.25 lb. , ai/acre.
90%, 80% & 50% (ai) wettable powder;
5% & 1.42% (ai) granular; 42.5% & 15.4%
(ai) flowable concentrates.
Usual Carrier:
Water
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3. Science Findings
Diphenamid related effects include increased liver weights and
slight histological changes in a chronic toxicity study in dogs.
Except for mild liver reactions in weanlings, this chemical
does not induce reproductive effects in rats. This pesticide
has shown low acute oral and dermal toxicity in test animals
and it is not an eye irritant. It is low in avian toxicity and
slightly to moderately toxic to fish and aquatic invertebrates.
Although the present data base for diphenamid does not indicate
major toxicological concerns, there are many toxicology data gaps:
including acute inhalation toxicity, primary dermal irritation,
dermal sensitization, subchronic dermal toxicity (21-day),
chronic toxicity (rat), oncogenicity in two species, teratology
in two species, mutagenicity and general metabolism studies.
In addition, the environmental fate, product chemistry, and the
metabolism in food crops, in ruminants and poultry for this
compound have not been characterized.
Chemical Characteristics :
Diphenainid is a white to off-white granular solid with a sweet
aromatic odor at room temperature. Its melting point is 133.8-
135.4° C, and its molecular weight is 239.3. Its water
solubility is 0.26 g/liter in water at 25°C.
Toxicological Characteristics :
Acute Oral: Toxicity Category III - 1,373 mg/kg (rats, both
sexes)
Acute Dermal: Toxicity Category III - > 6,320 mg/kg (rabbits,
both sexes)
Primary Eye Irritation: Toxicity Category IV - No irritation
with 0.1 ml solution (rabbits)
Chronic Toxicity:
In a 2-year dog feeding study, males and females were
offered diets containing 0, 120, 400, and 1200 ppm technical
diphenamid in the diet for 103 weeks. The only compound-
related effects included slightly increased liver weights and
a slightly increased incidence of portal macrophages and/or
fibroblasts in the livers of the dogs in the 400 and 1200 ppm
dose groups. The no-observed-effect level (NOEL) was determined
to be 120 ppm (3 mg/kg/day) in the diet.
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Human Exposure
Major routes of exposure: Applicators and mixer/loaders handling
this pesticide would be exposed primarily through skin contact
and inhalation.
Physiological & Biochemical Chracteristics :
Translocation: Diphenamid is absorbed by the roots and trans-
located through the roots, stem, and leaves.
Mechanism of pesticidal action: It inhibits growth in terminal
leaves and roots.
Metabolism & Persistence in Plants & Animals: The available
data are inadequate to evaluate the persistence of diphenamid
in plants and animals.
Environmental Chracteristics :
Available data are insufficient to fully assess the environmental
fate and potential exposure of humans and non-target organisms
to diphenamid. Additional data are required to characterize
the potential for diphenamid to reach ground water supplies.
Ecological Characteristics :
There is sufficient information to characterize technical
diphenamid as “slightly toxic” to freshwater invertebrates:
Daphnia inagna (LC 50 of 58.0 ppm). Formulations containing 50
technical were classified as very low in toxicity to avian
species: Bobwhite quail (LC 50 of 18,000 ppm) and Mallard duck
(LC 50 of 30,000 ppm), slightly toxic to warmwater fish: Bluegill
(LC 50 of 32.0 ppm) and moderately toxic to coidwater fish:
Rainbow trout (LC 50 of 1.2 ppm). In an acute contact study,
diphenainid was shown to be very low in toxicity to honey bees.
Endangered species
Since the registrant has voluntarily deleted the forestry use
pattern for diphenamid products, endangered species labeling
which would have been required under forestry uses will not
be required in this Standard.
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Tolerance Assessment
According to 40 CFR 180.230, tolerances for diphenarnid have been
approved for the raw agricultural commodities (RAC’s) listed
b e low.
Crop Tolerance(ppm)
Apples 0.10
Cattle, fat 0.05
Cattle, meat 0.05
Cattle, mbyp 0.05
Cottonseed 0.10
Cotton forage 0.20
Fruiting vegetables 0.10
Goat, fat 0.05
Goat, meat 0.05
Goat, mbyp 0.05
Hogs, fat 0.05
Hogs, meat 005
Hogs, rnbyp 0.05
Horses, fat 0.05
Horses, meat 0.05
Horses, mbyp 0.05
Milk 0.01
Okra 0.10
Peaches 0.10
Peanuts 0.10
Peanut, hay & forage 2.00
Peanut hulls 0.50
Potatoes 1 .00
Raspberries 1.00
Sheep, fat 0.05
Sheep, meat 0.05
Sheep, nibyp 0.05
Strawberries 1.00
Soybeans 0.10
Soybean, hay & forage 0.50
Sweet potatoes 0.10
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The Provisional Acceptable Daily Intake (PADI) for diphenamid is
based on the 103 week dog feeding study with a NOEL of 120 ppm
(3 mg/kg/day). Other toxicology data considered in suport of
these tolerances include a 3-generation rat reproduction study
indicating that reproductive performance was not affected at
dietary intake up to and including 30 mg/kg/day. Utilizing a
safety factor of 100, the PADI was calculated to be .03 mg/kg/day.
A Tolerance Assessment System (TAS) printout has recently been
completed which compares the PADI to the Theoretical Maximum
Residue Contribution (ThRC). The theoretical dietary exposure
expressed as a percentage of PADI utilized by the Theoretical
Maximum Residue Contribution (ThRC) ranged from 3.8% to 11.8% of
the PADI for various subgroups with 5.6% being the U.S. population
average.
Additional data are required for plant and animal metabolism,
analytical methods, and storage stability. Processing studies
are required for potatoes, soybeans, tomatoes, apples and peanuts.
Since the data required for individual commodities are dependent
on metabolism data, the Agency recommends that metabolism data
be obtained and submitted prior to any required residue data.
There is a Canadian tolerance of 1.0 ppm for diphenamid residues
in or on strawberries but no tolerances for residues of diphenamid
on the other raw agicultural commodities listed in 40 CFR 180.230.
There are no Mexican tolerances or Codex Maximum Residue Levels
for residues of diphenamid on the raw agicultural commodities
listed in 40 CFR 180.230.
Existing tolerances for soybean hay and forage; and peanut hay
are adequately supported by data. Therefore, the registrant may
propose removal of the grazing and feeding restrictions currently
in effect for diphenamid on soybeans and peanuts.
Reported Pesticide Incidences
The Pesticide Incident Monitoring System (PIMS) does not have
any incident involving diphenarnid at this time. Based upon data
from California, five incidences indicating skin or eye irritation
occurred from 1981 through 1985. Although four of the incidences
involved applicators and one involved a non-applicator, none of
these cases required hospitalization.
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4. Summary of Regulatory Positions & Rationale :
-- The Agency will not place diphenaxnid in Special Review be-
cause diphenamid does not exceed any of the risk criteria for
adverse effects in 40 CFR, Section 154.7. It does not pose a
risk of serious acute injury to humans, domestic animals or
avian species.
-- The Agency has determined that certain toxicological studies
are required to support the reregistration of diphenamid products:
acute inhalation, primary dermal irritation, dermal sensitization,
subchronic dermal toxicity (21-day), chronic toxicity in rats,
oncogenicity in two species, teratology in two species, mutageni-
city and metabolism studies.
-- The Agency has determined that present precautionary statements
for persons handling or applying diphenamid products are suffi-
cient for the labels of manufacturing-use and end-use products.
Available data indicate that diphenamid causes low oral (Category
IV) and dermal (Category III) toxicities in test animals and it
is not an eye irritant(Category IV). Therefore, the labeling
of these products contain statements that caution persons applying
or handling this compound, provide first aid instructions, and
require the use of precautionary measures to ensure safe handling
of the pesticide products.
-- The Agency will require the following environmental fate data
necessary to support the reregistration of diphenamid: photode-
gradation in water and soil, mobility (leaching & adsorptionf
desorption), mobility [ volatility (lab)], soil dissipation,
rotational crops (confined) and accumulation in fish studies.
-- The Agency has determined that certain groundwater data are
required. The necessary environmental fate data (aerobic and
anaerobic metabolism studies) are being repeated at the present
time. The Agency expects to receive these data by July 1987.
Until these data are received and found acceptable by the Agency,
data gaps for ground water exist.
-- The Agency has determined that reentry intervals for workers
are not required for diphenamid products. The low acute toxicity
of this chemical does not warrant significant concern about
exposure of workers reentering treated areas, according to the
criteria in 40 CFR Part 158.140.
--The Agency will require the following residue chemistry data
necessary to support the reregistration of diphenamid: plant and
animal metabolism, analytical methods, storage stability, and
processing studies for potatoes, soybeans, tomatoes, apples,
cottonseed and peanuts.
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-- The Agency has determined that grazing and feeding restrictions
for soybean hay and forage, and peanut hay are not required for
diphenamid products because existing tolerances for these corumo-
dities are adequately supported by residue chemistry data.
- -Since the registrant has voluntarily deleted the forestry use
patterns for diphenamid products, endangered species labeling
which would have been required under forestry uses will not be
required in this standard.
--This pesticide, when applied at recommended rates, does not
present unreasonable hazards to birds. Existing studies on
diphenamid indicate that its dietary toxicity to avian species
is very low.
5. Precautionary Statements
a. Manufacturing-Use Product Statements
All diphenaxnid products intended for formulation into
end-use products must bear the following statements:
“Do not discharge effluent containing this product into lakes,
streams, ponds, estuaries, oceans, or public water unless
this product is specifically identified and addressed in an
NPDES permit. Do not discharge effluent containing this
product into sewer systems without previously notifying the
sewage treatment plant authority. For guidance contact your
State Water Board or Regional Office of the EPA.”
b. End-Use Product Statements
The following precautionary statements must appear on the
following diphenarnid EP labels:
1. (Non-granular)
“Do not apply directly to water or wetlands (swamps, bogs,
marshes, and potholes). Do not contaminate water by
cleaning of equipment or disposal of wastes.”
2. (Granular)
“Cover, incorporate or collect granules spilled on the
soil surface. Do not contaminate water by cleaning of
equipment or disposal of wastes.”
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6. Summary of Major Data Gaps
The following data are required for this standard.
158.120 Product Chemistry data are required during 1988.
158.125 Residue Chemistry:
171-4 Nature of Residue (Plant & Animal
1etabol jam)
171-4 Residue Analytical Methods
171-4 Storage Stability
171-4 Residue Studies on Crops
171-4 Residue Studies on Processed
Food/Feed Commodities
158.135 Toxicology:
81-3 Acute Inhalation Toxicity (Rat)
81-5 Primary Dermal Irritation (Rabbit)
81-6 Dermal Sensitization (Guinea pig)
82-2 Subchronic Dermal (21-day)
83-1 Chronic Toxicity (Rat)
83-2 Oncogencity (Two species)
(Mouse) Ongoing Study*
(Rat)
83-3 Teratogenicity (Two species)
84-2 Mutagenicity
85-1 Metabolism
158.130 Environmental Fate
161-2 Photodegradation in Water
161-3 Photodegradation on Soil
162-1 Aerobic Soil Metabolism
162-2 Anaerobic Soil Metabolism
163-1 Mobility Studies (Leaching &
Adsorption! Desorption)
163-2 Mobility Studies (Volatility!
lab)
164—1 Soil Dissipation
165-1 Rotational Crops (Confined)
165-4 Accumulation in Fish
158.145 Wildlife and Aquatic Organisms
71-1 Avian Oral Toxicity
71-2 Avian Dietary Toxicity
(Two species)
72-1 Freshwater Fish Acute Toxicity
(Two psecies)
122-2 Aquatic Plant Growth
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7. Contact Person at EPA
Robert J. Taylor, P11-25
Office of Pesticide Programs, EPA
Registration Division (TS-767C)
401 M Street, S.W.
Washington, DC 20460
Phone (703) 557-1800
DISCLAIMER: The information presented in this Pesticide Fact Sheet
is for informational purposes only, and may not be used to fulfill
data requirements for pesticide registration or reregistration.
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