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pirimiphos-methyl (Actellic) Chemical Fact Sheet 6/85

                       CHEMICAL FACT SHEET FOR:
                                 ACTELLIC

FACT SHEET NUMBER: 59

DATE ISSUED:   JUNE 30, 1985


                    1.   DESCRIPTION OF CHEMICAL

- Generic Name:  0-[2-(diethylamino)-6-methyl-4-pyrimidinyl]0,0-
  dimethylphosphorothioate
- Common Name:  pirimiphos-methyl
- Trade Name:  Actellic
- EPA Shaughnessy Code:  108102
- Chemical Abstracts Service (CAS) Number:  29232-93-7
- Year of Initial Registration:  1984
- Pesticide Type:  Insecticide
- Chemical Family:  organophosphate
- U.S. and Foreign Producers:  ICI Americas, Inc., Imperial Chemical
  Industries, PLC., United Kingdom


                  2.  USE PATTERNS AND FORMULATIONS

- Application sites:  Stored grain products -- corn, rice, wheat, and
  grain sorghum intended for export only.
- Types of formulations:  emulsifiable concentrate
- Types and methods of application:  sprays
- Application rates:  0.006 to 0.015 lbs. a.i./l,000 lbs. of grain
- Usual carriers:  petroleum solvents


                         3.  SCIENCE FINDINGS

Chemical Characteristics

- Physical state:  liquid
- Color:  amber
- Odor:  putrid -- a typical organophosphorothioate odor.  Odorless when
  pure.
- Molecular weight:  305
- Melting point:  15-18 degrees C
- Boiling point:  Decomposes above 100 degrees C
- Vapor pressure:  1.1 x 10(-4) tor at 30 degrees C
- Flash point:  not reported
- Solubility in various solvents:  Solubility in water is 5 ppm at
  30 degrees C.  Miscible in all proportions with methanol, ethanol,
  chloroform, acetone, benzene, toluene, and xylene.


Toxicological Characteristics

- Acute oral LD50:  2050 mg/kg, Toxicity Category III
- Acute dermal LD50:  1505 mg/kg, Toxicity Category II
- Primary dermal irritation:  No irritation, Toxicity Category III
- Primary eye irritation:  Corneal opacity persisted to 14 days.
  Toxicity Category III.
- Skin sensitization:  Not a sensitizer.
- Acute inhalation:  Uncharacterized.  The use pattern precludes
  inhalation exposure.
- Neurotoxicity:  Not an acute delayed neurotoxic agent at doses up
  to 10 mg/kg/day for 90 doses.
- Oncogenicity:  Not shown to be an oncogen in rat or mouse studies
  at dose levels up to 300 and 500 ppm (highest dose tested),
  respectively.
- Teratogenicity:  The Agency has determined that this chemical is not
  teratogenic at levels up to 16 mg/kg/day; however, an additional
  study in a second species (rats) is still required.
- Reproduction, 3-generation:  Two studies adequately demonstrate that
  pirimiphos-methyl does not produce reproductive effects.  No effects
  were demonstrated at dose levels up to 100 ppm.
- Metabolism:  The studies suggest that pirimiphos-methyl is rapidly
  excreted, and no evidence of bioaccumulation was noted.
- Mutagenicity:  This chemical has been determined to be non-mutagenic
  in all three required studies.


Physiological and Biochemical Behavioral Characteristics

- Mechanism of pesticidal action:  An insecticide which is active by
  contact, ingestion, and vapor action, and causes phosphorylation of
  the acetylcholinesterase enzyme of tissues, allowing accumulation
  of acetylcholine at cholinergic neuro-effector junctions (muscarinic
  effects), and at skeletal muscle myoneural junctions and autonomic
  ganglia.  Poisoning also impairs the central nervous system function.
- Symptoms of poisoning include:  Headache, dizziness, extreme
  weakness, ataxia, tiny pupils, twitching, tremor, nausea, slow
  heartbeat, pulmonary edema, and sweating.  Continual absorption at
  intermediate dosages may cause influenza-like illness which includes
  symptoms like weakness, anorexia, and malaise.
- Metabolism and persistence in plants and animals:  The metabolism of
  pirimiphos-methyl in plants and animals is not, at this time,
  adequately understood in order to establish a tolerance for grain
  crops.


Environmental Characteristics

- Uncharacterized.  This use pattern precludes exposure to the
  environment.


Ecological Characteristics

- Avian oral:  mallard duck, 76.6 mg/kg
               ring-necked pheasant, 17.7 mg/kg.
- Avian dietary:  mallard duck, 633 ppm
                  bobwhite quail, 207 ppm.
- Freshwater fish:  coldwater fish (rainbow trout), 0.40 ppm
                    warmwater fish (bluegill sunfish), 2.9 ppm.
- Acute freshwater invertebrates:  Daphnia, 0.21 ppb

Tolerance Assessment

- No domestic tolerances exist for this chemical.  Tolerances for small
  grains have been proposed to support domestic consumption of treated
  grains.  There is an established tolerance of 5 ppm for imported
  kiwifruit.


Summary Science Statement

- Pirimiphos-methyl is an organophosphorothioate compound with
  moderate acute toxicity.  This chemical has demonstrated adverse
  chronic effects.  It is also a moderate toxicant to wildlife
  species; however, the registered use precludes exposure to wildlife.
- This chemical is toxic to fish and other wildlife.  The proposed
  use precludes any impact on endangered species.
- In case of a significant chemical spill, call 1-800-426-9300
  (CHEMTREC).


                 5.  SUMMARY OF MAJOR DATA GAPS

- A second mammalian species (rat) teratology study.


                      6.  CONTACT PERSON AT EPA

Jay S. Ellenberger
Product Manager (12)
Insecticide-Rodenticide Branch
Registration Division (TS-767C)
Office of Pesticide Programs
Environmental Protection Agency
401 M Street S.W.
Washington, DC  20460

Office location and telephone number:
Room 202  Crystal Mall #2
1921 Jefferson Davis Highway
Arlington, VA  22202
(703) 557-2386


DISCLAIMER:  THE INFORMATION PRESENTED IN THIS CHEMICAL INFORMATION FACT 
SHEET IS FOR INFORMATIONAL PURPOSES ONLY AND NOT TO BE USED TO FULFILL 
DATA REQUIREMENTS FOR PESTICIDE REGISTRATION AND REREGISTRATION.