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demeton (Systox) Chemical Fact Sheet 2/85

                      CHEMICAL FACT SHEET FOR:
                                DEMETON

FACT SHEET NUMBER:  45

DATE ISSUED:  FEBRUARY 27, 1985

                    1. DESCRIPTION OF CHEMICAL

- Chemical Name: Mixture of 2 isomers consisting of: O,O-diethyl
  O-[2(ethylthio) ethyl] phosphorothioate and O,O-diethyl 5-[2
  (ethylthio) ethyl] phosphorothioate.

- Common Names:  demeton-O + demeton-S, mercaptophos, and mercaptophos
  teolevy (USSR)
- Trade Name:  Systox
- EPA Shaughnessy No.:  057601
- Chemical Abstracts Service (CAS) Number:  8065-48-3
- Year of Initial Registration:  July 15, 1955
- Pesticide Type:  Systemic acaricide/insecticide
- Chemical Family:  Organophosphate
- U.S. Producer:  Mobay Chemical Corporation


                 2. USE PATTERNS AND FORMULATIONS

- Application sites:  vegetable, field, orchard, and ornamental
  (including greenhouse)
- Types of formulations:  liquid and granular
- Types/methods of application:  ground or air
- Efficacy review results, where conducted:  N/A


                       3. SCIENCE FINDINGS

Chemical characteristics

- Light brown liquid; odor characteristic of sulfur compounds; soluble
  in most organic solvents; subject to hydrolysis under alkaline
  conditions; molecular weight 258.32.

Toxicological Characteristics

- Toxicity Category I by dermal route of exposure (14 mg/kg for male
  rats and 8.2 mg/kg for female rats; Toxicity Category I by the oral
  route of exposure (6.2 mg/kg for male rats and 2.5 mg/kg for female
  rats); positive in mutagenicity studies in vitro in cells; data
  gaps exist in the area of neurotoxicity, chronic toxicity, oncogeni-
  city, teratogenicity, and reproduction. A gene mutation assay in
  mammalian cells in culture and a chromosome aberration assay in
  vivo are required to be performed to assess the mutagenic potential
  of demeton.

Physiological and Biochemical Behavioral Characteristics

- Readily absorbed and translocated by plants; cholinesterase inhibitor.

Environmental Characteristics

- No data are available to assess the environmental fate of demeton; no
  data are available to assess demeton's potential for contaminating
  groundwater.

Ecological Characteristics

- Highly toxic to birds (7.19 mg/kg for mallard duck and 8.21 mg/kg for
  pheasant); highly toxic to fish (0.1 ppm for bluegill sunfish and 0.6
  ppm for rainbow trout); very highly toxic to freshwater invertebrates
  (0.014 ppm for Daphnia pulex); special tests to monitor the resi-
  dues of demeton on avian feed items and aquatic sites are required;
  interim labeling to protect endangered species to be imposed in time
  for the 1986 growing season if the generic (cluster) analysis has not
  been completed.

Tolerance Assessments

- Refer to the attached table for the list of current tolerances
  established for demeton; available data are not sufficient to conduct
  a full tolerance assessment.


            4. SUMMARY OF REGULATORY POSITION AND RATIONALE

- Use classification: All end-use products containing demeton shall
  continue to be classified for restricted use.
- Formulation or geographical restrictions: None
- Unique warning statements required on labels: end-use (EP) products
  require the use of protective clothing, rubber gloves, rubber
  overshoes, and goggles; reentry of 48 hours; and a crop rotation
  restriction.


                    5. SUMMARY OF MAJOR DATA GAPS

Toxicology:

  82-1    90-day feeding, rodent, non-rodent            June, 1986
          90-day feeding, rat, thiol sulfoxide          January, 1986
  82-2    21-day dermal toxicity, rabbit                August, 1985
  81-7    Delayed neurotoxicity, hen                    August, 1985
  83-1    Chronic toxicity                              March, 1985
  83-2    Oncogenicity                                  December, 1987
  83-3    Teratogenicity                                December, 1985
  83-4    Reproduction                                  December, 1987
  84-2    Gene mutation assay in mammalian cells        August, 1985
            in culture
          Chromosome aberration assay in vivo           August, 1985
  85-1    General metabolism                            March, 1986

Environmental Safety:

  70-1    Special test - monitoring of residues on     September, 1986
            avian feed items
  70-1    Special test - monitoring of residues in     September, 1986
            aquatic sites
  70-3    Acute toxicity to estuarine and marine       September, 1986
            organisms

Environmental Fate:

  161-1   Hydrolysis                                   March, 1985
  161-2   Photodegradation in water                    March, 1985
  161-3   Photodegradation in soil                     March, 1985
  161-4   Photodegradation in air                      August, 1985
  162-1   Aerobic soil metabolism                      June, 1986
  162-2   Anaerobic soil metabolism                    June, 1986
  162-3   Anaerobic aquatic metabolism                 June, 1986
  163-1   Leaching and adsorption/desorption           March, 1985
  163-2   Volatility (lab)                             August, 1985
  164-1   Soil dissipation                             June, 1986
  164-3   Forestry                                     March, 1987
  165-1   Rotational crops (confined)                  March, 1987
  165-2   Rotational crops (field)                     March, 1988
  165-4   Accumulation in fish                         February, 1988
  132-1   Reentry data                                 March, 1988
  201.1   Droplet size spectrum testing and drift      February, 1987
            field evaluation

Residue Chemistry:

  171-4 Residues in livestock                          February, 1987
  171-4 Residues analytical method                     February, 1987
  171-4 Storage stability                              February, 1987
  171-4 Residue data on crops                          February, 1987

Product Chemistry:

  61-2    Description of beginning materials and       March, 1985/
            manufacturing process                      August, 1985
  61-3    Discussion of the formation of impurities        -do-
  62-1    Preliminary analysis                         March, 1985/
                                                       August, 1985
  62-2    Certification of ingredient limits               -do-
  62-3    Analytical methods to verify certified limits    -do-
  63-     Physical/chemical properties                     -do-

                      6. CONTACT PERSON AT EPA

William H. Miller (PM-16)
Insecticide-Rodenticide Branch (TS-767)
U.S. Environmental Protection Agency
401 M Street N.W.
Washington, DC 20460
(703)557-2600

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.