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perfluidone (Destun) Herbicide Profile 9/85

             CHEMICAL FACT SHEET FOR  PERFLUIDONE
FACT SHEET NUMBER: 74
DATE ISSUED: SEPTEMBER 30, 1985
                    1. DESCRIPTION OF THE CHEMICAL
- Generic Name: 1,1,1-trifluoro-N-[2-methyl-4-(phenylsulfonyl)phenyl]-
  methanesulfonamide
- Empirical Formula:  C14H12F3N04S2
- Common Name:  perfluidone
- Trade Name:  Destun
- EPA Shaughnessy Code:  108001
- Chemical Abstracts Service (CAS) Number:  37924-13-2
- Year of Initial Registration:  1976
- Pesticide Type:  herbicide
- Chemical Family:  sulfonamide
- U.S. Producer:  3M Company
                 2. USE PATTERNS AND FORMULATIONS
- Application sites:  Perfluidone is registered for control of nutsedge
  species, certain grasses, and broadleaf weeds in flue-cured tobacco.
- Type of formulation:  Perfluidone is available in a wettable powder
  formulation.
- Types and methods of application: Perfluidone is banded or broadcast
  applied to the soil surface with ground equipment as a preemergence
  spray .
- Application rates:  1.5 lbs. a.i./A on crop sites. 
- Usual carriers: Water.
                       3. SCIENCE FINDINGS
Chemical Characteristics
- Perfluidone is a solid at room temperature and is odorless. Its
  molecular weight is 379.40. The melting point is 143-145 degrees C.
  Perfluidone is soluble in water (at 20 C) to 60.0 ug/ml and soluble in
  aromatic and chlorinated hydrocarbon solvents.
Toxicological Characteristics
- Acute toxicology effects of perfluidone are as follows:
  - Acute dermal toxicity in rabbits: >4,000 mg/kg body weight,
    Toxicity Category III.
  - Skin irritation in rabbits:  Not an irritant, Toxicity Category IV.
  - Eye irritation in rabbits: Moderate eye irritant, Toxicity
    Category II.
- Subchronic toxicology effects of perfluidone are as follows:
  - A 90-day dog feeding study showed liver disorders (hepatic lesions,
    hepatocyte vacuolation, hyaline degeneration, and biliary stasis) at
    the two highest dose levels (400 and 800 ppm).
- Chronic toxicology effects on perfluidone have not been evaluated,
  because there are no valid teratogenicity studies in either the rat or
  rabbit, and no mutagenicity tests.
- Major routes of human exposure: Non-dietary exposure of applicators to
  perfluidone during mixing, loading, spraying, and flagging is
  probable.
Physiological and Biochemical Behavioral Characteristics
- Translocation: Perfluidone is mobile in the xylem, but is of limited
  mobility in the phloem. - Mechanism of pesticidal action: Perfluidone
  inhibits photosystem I of the photosynthetic process.
Environmental Characteristics
- Adsorption and leaching in basic soil types: Perfluidone will leach
  through wet, neutral or slightly alkaline soils, with a tendency
  toward greater leaching in soils having low clay and organic matter. 
  Leaching occurs to a lesser extent in acidic soil.
- Microbial breakdown:  Soil microorganisms play a significant role in
  the degradation of perfluidone in the soil. 
- Loss from photodecomposition and/or volatilization: Photodecomposition
  and/or volatilization play an important role in the degradation of
  perfluidone on or in soil.
- Average persistence at recommended rates:  When used at recommended
  rates under normal environmental conditions, the half-life of
  perfluidone in the soil is approximately one month.
Ecological Characteristics
- 96-hour toxicity:  147.5 ppm for bluegill sunfish (practically
  nontoxic), and 17.0 ppm for rainbow trout (slightly toxic).
- Potential problem for endangered species: Perfluidone was reviewed by
  the Agency under the endangered species cotton cluster, but it did not
  exceed any trigger. On flue-cured tobacco, if the maximum rate of 1.5
  pounds a.i./acre was applied to 6 inches of water the resulting
  residues (0.754 ppm) would be less than 0.900 ppm (1/20 of the LC50 of
  the most sensitive fish). Therefore, perfluidone's use on tobacco is
  not expected to adversely affect the endangered species, and no
  endangered species label statements are required.
Tolerance Assessment
- The Agency is not conducting a tolerance reassessment on perfluidone,
  because the only use is on flue-cured tobacco.  This use is a nonfood
  and non-feed use which does not require a tolerance.  Therefore, the
  Agency will not require residue chemistry data on the metabolism of
  perfluidone and related metabolite(s) in crops and animals.
Problems Known to Have Occurred with Use
- Since perfluidone has never been commercially manufactured or sold in
  the United States, it has not been identified in the Pesticide
  Incident Monitoring System (PIMS), nor implicated in any incident.
Summary Science Statement
- Perfluidone is not acutely toxic by the dermal and ocular routes of
  exposure. A 90-day dog feeding study showed liver disorders (hepatic
  lesions, hepatocyte vacuolation, hyaline degeneration, and biliary
  stasis) at the two highest dose levels (400 and 800 ppm).
- The available data are insufficient to show that any of the risk
  criteria listed in Section 162.11(a) of Title 40 of the U.S. Code of
  Federal Regulations have been met or exceeded for the uses of
  perfluidone at the present time. There are no valid mutagenicity and
  teratogenicity studies for perfluidone. There are also residue
  chemistry and environmental fate data gaps.
- Perfluidone is slightly toxic to freshwater fish species. Studies
  regarding freshwater invertebrates are not acceptable, and there are
  no marine/estuarine data. A detailed ecological hazard assessment
  cannot be made until certain environmental chemistry data requirements
  have been met.
             4.  SUMMARY OF REGULATORY POSITION AND RATIONALE
- Based on the review and evaluation of all available data and other
  relevant information on perfluidone, the Agency has made the following
  determinations:
  - The available data are insufficient to indicate that any of the risk
    criteria listed in Section 162.11(a) of Title 40 of the U.S. Code of
    Federal Regulations have been met or exceeded for the uses of
    perfluidone at the present time.
  - Perfluidone is not acutely toxic by the dermal and ocular routes of
    exposure. A 90-day dog feeding study showed liver disorders
    (hepatic lesions, hepatocyte vacuolation, hyaline degeneration, and
    biliary stasis) at the two highest dose levels (400 and 800 ppm).
  - The absence of other toxicological data prevents the Agency from
    determining the acute, subacute, and chronic effects of perfluidone.
    Given the lack of data, the most appropriate action is to move
    quickly to fill the data gaps. When data are submitted and reviewed,
    the Agency will determine the registrability of the affected use
    pattern. - The data base supporting the perfluidone tolerance on
    cottonseed (0.01 ppm) has been reviewed and found to be inadequate.
    However, the data tables in the perfluidone registration standard
    will not include these data gaps attributable to the tolerance on
    cottonseed: Section 158.135 Toxicology - Subchronic Testing (82-4),
    Chronic Testing (83-1, 83-2, 83-3), Special Testing (85-1); Section
    158.125 Residue Chemistry - Livestock (171-4), Animal Residues 
    (171-4), Cottonseed (171-4), and Meat/Milk/Poultry/Eggs (171-4).
    Instead, the Agency will issue a Proposed Rule to revoke the
    perfluidone tolerance on cottonseed. If there is no response to
    support the tolerance, the Agency will issue a Notice of Tolerance
    Revocation.
- End-use product (EP) labels will be required to bear a revised
  environmental hazard statement.
- EP labels will be required to bear a rotational crop restriction.
- EP labels will be required to bear a protective clothing statement for
  mixers, loaders, and applicators.
- Manufacturing-use product (MP) labels will be required to bear a
  statement regarding discharge to bodies of water and sewer systems.
- The Agency will not require a groundwater advisory statement at this
  time. If additional data indicate that perfluidone may cause
  groundwater concerns. the Agency may reconsider this decision.
- No endangered species label statements are required.
- The Agency is not requiring a reentry interval for the registered
  use of perfluidone.
- Specific label warning statements:
  - Hazard Information:  The human hazard statements must appear on all
    EP labels as prescribed in 40 CFR 162.10. - Environmental Hazard
    Statements: All MP's intended for formulation into EP's must bear
    the following statements: Do not discharge effluent containing this
    product directly into lakes, streams, ponds, estuaries, oceans, or
    public waters unless this product is specifically identified and
    addressed in a National Pollutant Discharge Elimination System
    (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 Environmental Protection Agency. 
- End-use Product Statements:
  - The following environmental hazard statement must appear on all EP
    products: Do not apply directly to water or wetlands. Do not
    contaminate water by cleaning of equipment or disposal of wastes.
  - The following rotational crop restriction statement must appear on
    all EP products: Limitations: Replant only tobacco in DESTUN
    herbicide-treated soil during the year of application and the
    following crop year.
  - The following protective clothing statement must appear on all
    EP products:  During mixing/loading or application, wear gloves
    impermeable to perfluidone.  When handling the concentrated product,
    wear a dust mask and chemical-resistant apron in addition to the
    gloves.  Wash hands thoroughly with soap and water after handling
    and before eating, urinating, or smoking,  Remove and wash clothing
    before reuse.  Clothing should be laundered separately from
    household articles.  Replace gloves frequently.  Used gloves and
    clothing which has been drenched or heavily contaminated should be
    disposed of in accordance with state or local regulations.
                     5.  SUMMARY OF MAJOR DATA GAPS
- The toxicological studies are required on the following dates:
  - An acute oral toxicity study, June 30, 1986.
  - An acute inhalation toxicity study, June 30, 1986. 
  - A dermal sensitization study, June 30, 1986.
  - A 21-day dermal toxicity study, September 30, 1986.
  - Two teratogenicity studies, December 30, 1986.
  - Mutagenicity studies, June-September, 1986.
- The environmental fate data are required on the following dates:
  - A hydrolysis study, June 30, 1986.
  - A photodegradation study, June 30, 1986.
  - An aerobic soil study, December 30, 1987.
  - A mobility/leaching study, September 30, 1986.
  - A dissipation/soil study, December 30, 1987.
- The ecological effects data are required on the following dates:
  - An acute avian oral toxicity study, June 30, 1986.
  - Two avian subacute dietary toxicity studies, June 30, 1986.
  - Two freshwater fish toxicity studies, June 30, 1986.
  - An acute freshwater invertebrate toxicity study, June 30, 1986.
- Product chemistry data are required during 1986.
                       6.  CONTACT PERSON AT EPA
Robert J. Taylor
Office of Pesticide Programs
Registration Division (TS-767C)
Fungicide-Herbicide Branch
401 M Street S.W.
Washington, DC  20460
703/557-1800
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.