United States Offio* of Pe«tWde» and Toxic
Environmental Protection office of PactleMe Programs (TS-766C)
Agency Washington. DC 20460
Pesticide
Fact Sheet
Name of Chemical: ETHOPROP
Reason for Issuance: Registration Standard Arnendment-
n«*« !«.«..«^. Classification for restricted use
Date Issued: 2/1/35
Fact Sheet Number: 3.1
1. Description of chemical;
Generic name: 0-ethyl S,S-dipropyl phosphorodithioate
Common name: ethoprop
Trade name: Mocap*
EPA Shaughnessy code: 041101
Chemical Abstracts Service (CAS) number: 13194-84-4
Year of initial registration: 1967
Pesticide type: soil insecticide-nematicide
Chemical family: organophosphate
U.S. and foreign producers: Rhone-Poulene, Inc.
2. Use patterns and formulations;
Application sites: registered for use on a variety of
tropical fruits, vegetables, ornamentals, field crops,
commercial turf, and home lawns.
Types of formulations: granulars, emulsifiable concentrates.
Types and methods of application: applied as a soil in-
corporated, broadcast, or band treatment, as a root dip
treatment for citrus and certain ornamentals. Ethoprop
formulations are commonly applied by using ground equip-
ment and are incorporated into the soil immediately
after application with the use of cultivating equipment
and/or by irrigation. Also, spray equipment (i.e.,
backpack sprayers) and watering cans may be used for
application.
Application rates: vary according to formulation and crop.
Usual carriers: Confidential Business Information
3. Science findings:
Summary science statement:
Adequate studies are available to assess the acute toxi-
cological hazards of technical ethoprop. No toxicological
hazards of concern were identified. Available studies
indicate that ethoprop is very toxic to birds, marine/
estuarine crustaceans and fish species. It is moderately
toxic to coldwater fish species and moderately toxic to
honeybees.
Although a full tolerance and risk assessment cannot be
completed due to a number of data gaps, there is no evidence
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fact suggest that current tolerances are likely to expose
the public to unreasonable adverse effects.
Chemical characteristics :
Ethoprop is a clear yellow—tinted liquid with a strong
mercaptan odor. The empirical formula is C 8 H 19 0 2 PS 2
and the molecular weight is 242.307. The boiling point
is 86—91°C at 0.2 mmHg. Ethoprop is soluble in water to
750 ppm and soluble in most organic solvents.
Toxicological characteristics :
Currently available toxicology studies on ethoprop are as
follows:
— Oral LD 50 in rats: 56.2 mg/kg for males and 30.2 ink/kg
for females.
— Dermal LD5o in rabbits: 23.7 ui/kg
— Primary dermal irritation: Unknown since death prevented
manifestation of a skin irritation response.
— Primary eye irritation: Unknown since all rabbits
died within 1 hr of administration. Substance is
too toxic to determine an eye irritation potential.
— Inhalation LC 50 : 0.123 mg/liter
— Acute delayed neurotoxicity: Hens treated with ethoprop
were not shown to produce signs of delayed neurotoxicity.
— Teratology in rats: Maternal NOEL l.6 mg/kg; terata
NOEL=l.6 ink/kg
— 90—day dog feeding study: Systemic NOEL=lOO ppm at
the highest dose tested; cholinesterase NOEL=l ppm.
Adequate studies are available to assess the acute toxi-
cological effects of technical ethoprop. No toxicological
hazards of concern have been identified in the studies re-
viewed for the Standard.
Physiological and biochemical behavioral characteristics :
Metabolism and persistence in plants and animals: ethoprop
in bean and corn plants is metabolized by hydrolysis
following uptake from the soil. The metabolites identi-
fied are ethyl propyl sulfide, propyl disulfide, ethyl
propyl sulfoxide and water soluble high—boiling phosphoric
acids and/or their salts. The only residue of toxi-
cological concern is the parent compound.
There are no data to indicate how ethoprop is metabolized
or excreted by animals. In one feeding study in which
dogs were fed unlabeled ethoprop for 21 days at rates
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Ethop op
fact sheet
up to 2.3 ppm of their diet, no detectable residues
(i.e. >0.01 ppm) were found in their tissues. Because
feed items with established negligible residue tolerances
(<0.02 ppm) are expected to have little, if any, ethoprop
residues, it is concluded that the metabolism in animals,
although not completely known, is at this time sufficiently
detailed.
Environmental characteristics :
Ethoprop is not expected to contaminate drinking water
supplies. It degrades fairly rapidly with half—lives of
3—56 days in soil. Increase in soil temperature tends to
increase the dissipation rate. However, ethoprop is very
mobile in sandy soil and has a potential for contaminating
groundwater in areas of sandy soil with a high water table.
Because of this, soil dissipation study monitoring may,
depending on the leaching data, have to be conducted at a
depth greater than 6 inches.
Ecological characteristics :
Based on studies available to assess hazards to wildlife
and aquatic organisms, ethoprop is characterized as very
highly toxic to birds, marine/estuarine crustaceans, and
marine/estuarine fish species. It is moderately to highly
toxic to coidwater fish species and moderately toxic to
honey bees.
Results of currently available studies are as follows:
— avian oral LD 50 : ranges from 4.21 — 61 mg/kg.
— avian dietary LC 50 : ranges from 33 — 118 ppm in
upland gamebirds and 287 — 550 ppm in waterfowl.
— fish LC 50 : ranges from 1.02 mg/i — 1.85 mg/i in
rainbow trout.
— aquatic invertebrate LC 50 : ranges from 13 ugh —
25.3 ugh.
Tolerance assessment :
Tolerances are established for negligible residues of the
insecticide nematicide ethoprop in or on the following raw
agricultural commodities: bananas, cabbage, corn—grain,
corn fodder and forage, cucumbers, fresh corn including
sweet corn (kernels plus cob with husk removed), lima
beans, lima bean forage, peanuts, peanut hay, pineapples,
pineapple fodder and forage, soybeans, soybean forage and
hay, sugarcane, sugarcane fodder and forage, and sweet
potatoes at 0.02 parts per million. These tolerances are
published in 40 CFR 180.262. There are no international
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pg. 4 revised 2/85
Ethoprop 4
fact sheet
tolerances nor Codex Maximum Residue Limits (MRLs) for
residues of ethoprop.
Tolerances for most raw agricultural commodities (with
the exception of potatoes and tobacco) are supported by
currently available residue data. However, the Agency is
unable to complete a tolerance reassessment because of
residue chemistry and toxicology data gaps.
A provisional acceptable daily intake (PADI) is calculated
to be 0.000075 mg/kg/day, the provisional maximum permiss-
ible daily intake (PMDI) is 0.0045 mg/day and the theo-
retical maximum residue concentration (TMRC) is 0.0052
mg/day for a 1.5 kg diet. The percent of the PADI utilized
is 115.02%. Although the PADI has been exceeded, it is
concluded that exceeding the PADI does not necessarily in
and of itself represent an immediate hazard to the public.
The actual levels of residues to which the public is
exposed are likely to be considerable less than this
theoretical maximum would indicate for some of the following
reasons:
— Not every crop for which a tolerance has been estab—
lished has been treated with the pesticide.
— Most treated crops have residue levels which are
below the established tolerance level.
— Processing or time to market often result in further
residue reductions.
— Preparing food for consumption often results in
residue reductions.
— Not all crops contributing to the TMRC (PADI) are
likely to be consumed by an individual.
— Market basket surveys conducted by FDA indicate that
little if any real pesticide residues of organophos—
phates actually remain in/on finished foods.
After review of the requested toxicology data, the ADI will
be reevaluated.
4. Summary of regulatory position and rationale :
The Restricted Use’ classification for all ethoprop
emulsifiable concentrate formulations containing 40% and
greater will continue. Granular end—use products con-
taining 10% or more ethoprop with disulfoton 5% and greater
are classified for ‘Restricted Use”. All other granular
and/or fertilizer end—use products containing ethoprop are
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Etboprop
fact sheet
also classified “gestricted—Use”, however, registrants of
these products have the option of accepting the restricted-
use classification, or submitting data to show that the
the product does not warrant this restriction. All
such products released for shipment on September 1,
1985, or thereafter, must be labeled for restricted use.
Similarly, all such products which are in channels ot
trade on or after September 1, 1986 must bear restricted
use labeling.
Although the Agency is unable to complete a tolerance
reassessment because of certain residue chemistry and
toxicology data gaps, the Agency concludes that no change
in present tolerances are indicated at this time.
Further, although the provisional acceptable daily intake
has been exceeded, future requests for tolerances will
not be automatically rejected on this basis.
No federal or state reentry intervals have been
established for ethoprop. There is no need to establish
any reentry intervals, since the practice of soil incor-
poration is expected to minimize exposure during reentry
operations. This is also true for turf areas where the
pesticide is watered—in.
The Agency has identified a potential aviari adverse effect
concern. Based on acceptable subacute dietary studies,
it is calculated that the expected residues on avian
food—stuffs following a single application of ethoprop at
a rate of 6 pounds a.i. per acre (maximum registered corn
rate) exceed the subacute dietary LC 50 level in avian
species. In order to determine whether significant
evidence relating to this adverse effect would raise
prudent concerns of unreasonable adverse risk to man or
the environment, the Agency is requiring additional
avian field testing data.
The following additional human hazard statement must
appear on all manufacturing—use product labels:
“Poisonous if absorbed through the eye.
Do not get in eyes.”
Although a full tolerance reassessment and risk assessment
cannot be completed, there is no evidence to suggest that
current tolerances are likely to expose the public to
unreasonable adverse effects.
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Etbprop 6
fact sheet
5. Summary of major data gaps :
— 90—day feeding; rodent, non—rodent
— 21-day dermal
— chronic toxicity; 2 species
— oncogenicity study; 2 species
— teratogenicity; 1 species
— reproduction; 2 species
— mutagenicity testing; gene mutation, chromosomal
aberration, other mechanisms of mutagenicity
— general metabolism
hydrolysis study
— photodegradation study; in water
— aerobic and anaerobic soil study
— leaching and adsorption/desorption study
— field soil dissipation study
— accumulation studies; rotational crops and fish
— data on residues in potatoes and tobacco
— 2 acute field studies,
— freshwater fish LC 50
— acute LCSO freshwater invertebrates
All studies are to be submitted to the Agency by June, 1986.
6. Contact Person at EPA
William H. Miller
Product Manager (16)
Registration Division (TS—767C)
Insecticide—Rodenticide Branch
Environmental Protection Agency
Washington, DC 20460
Tel. No. (703) 557—2600
Disclaimer: The information presented in this Chemical
Information Fact Sheet is for informational purposes only
and may not be used to fulfill data requirements for
pesticide registration and reregistration.
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