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Propachlor (Ramrod, Bexton) Herbicide Profile 2/85

                        CHEMICAL FACT SHEET FOR:
                                Propachlor
FACT SHEET NUMBER: 44
DATE ISSUED: FEBRUARY 11, 1985
               1. DESCRIPTION OF THE CHEMICAL
- Generic Name:  2-chloro-N-isopropylacetanilide (C11H14ClNO)
- Common Name:  propachlor
- Trade Names:  Ramrod, Bexton, and CP 31393
- EPA Shaughnessy Code:  019101
- Chemical Abstracts Service (CAS) Number:  1918-16-7
- Year of Initial Registration:  1965
- Pesticide Type:  Herbicide
- Chemical Family:  alpha-chloroacetamide
- U.S. Producer:  Monsanto Company
               2. USE PATTERNS AND FORMULATIONS
- Application sites:  Propachlor is registered for use as a preemergence
  herbicide on corn (all types), soybeans (seed only), grain sorghum
  (milo), green peas, pumpkins, cotton, and flax.  In corn, propachlor
  can also be applied as an early postemergence control.  Sorghum is the
  largest use site for propachlor, accounting for most uses of the wet-
  able powder formulation.  Corn is the second largest use site for
  propachlor, accounting for most uses of the granular formulation.
- Types of formulations:  Propachlor is available in granular, wettable
  powder, and flowable liquid concentrate formulations.
- Types and methods of applications:  Propachlor is applied as a pre-
  emergence broadcast spray or banded ground application, and only one
  application is allowed per year.
- Application rates:  3.0 to 6.0 lbs. a.i./A on crop sites.
- Usual carriers:  Attapulgite/montmorillonite clay and water.
                       3. SCIENCE FINDINGS
Chemical Characteristics
- Propachlor is a light tan solid at room temperature, and its molecular
  weight is 211.70.  The boiling point is 110 degrees C at 0.3 mm Hg.
  Propachlor is soluble in most organic solvents and in water (at 23
  degrees C) to 693 ppm.
Toxicological Characteristics
- Acute toxicology effects of propachlor are as follows:
  - Acute oral toxicity in rats:  1.80 g/kg body weight, Toxicity
    Category III.
  - Acute dermal toxicity in rabbits:  >20.0 g/kg body weight,
    Toxicity Category IV.
  - Skin irritation in rabbits:  slight irritant, Toxicity Category III.
  - Eye irritation in rabbits:  Corrosivity and corneal opacity not
    reversible within seven days, Toxicity Category I.
- Chronic toxicology effects of propachlor are as follows:
  - A teratology test in rats has shown that propachlor tested at the
    highest dose level (HDT) failed to induce teratogenic, fetotoxic,
    or maternal effects.  The HDT was 200 mg/kg/day.
- Major routes of human exposure:
  - Non-dietary exposure to propachlor by a farmer as an applicator
    during mixing, loading, spraying, and flagging is probable.
  - Exposure of humans to propachlor through contamination of ground-
    water and runoff contamination of surface water after heavy spring
    precipitation is probable.
  - The dietary exposure (mg/kg/day) to propachlor by the U.S. popula-
    tion from treated food crops is possible.
Physiological and Biochemical Behavioral Characteristics
- Absorption characteristics:  Propachlor is adsorbed mainly by
  germinating seedling shoots, secondarily by roots.
- Translocation:  Propachlor is translocated throughout the plant,
  mainly in the vegetative tissues.
- Mechanism of pesticidal action:  Propachlor is a strong inhibitor of
  cell elongation and protein synthesis.
- Metabolism in plants:  Metabolized rapidly in plants.
Environmental Characteristics
- Adsorption and leaching in basic soil types:  Propachlor is absorbed
  by soil colloids.
- Microbial breakdown:  Microbes are the primary factor in the break-
  down of propachlor in soils.
- Loss from photodecomposition and/or volatilization:  Low
- Average persistence at recommended rates:  Half-life of 4 to 6
  weeks; longer in soils high in organic matter.
Ecological Characteristics
- Avian acute oral toxicity:  91 mg/kg
- Avian 8-day dietary toxicity (Bobwhite quail):  >5,000 ppm
- Avian 8-day dietary toxicity (mallard duck):  >5,000 ppm
- 96-hour fish toxicity:  >1.40 ppm for bluegill sunfish (moderately
  toxic) and 0.17 ppm for rainbow trout (highly toxic).
- 48-hour aquatic invertebrate toxicity:  7.80 ppm (moderately toxic)
  for Daphnia magna
- Potential problem for endangered species:  The Office of Endangered
  Species (USDI) has determined that propachlor use on corn, sorghum,
  or soybeans may impact the following endangered species:  Slackwater
  darter, 11 freshwater mussels, Woundfin, and Salanograss.
Tolerance Assessment
- The Agency is unable to complete a full tolerance reassessment of
  propachlor because of certain residue chemistry data gaps.  The
  additional residue data requirements may cause specific tolerances
  to be revised in the future.
- The tolerances listed below have not been revised:
  Commodities                                  parts per million
  Beets sugar, roots                                   0.2
  Beets sugar, tops                                    1.0
  Cattle, fat                                          0.02
  Cattle meat by-products                              0.02
  Cattle meat                                          0.02
  Corn, forage                                         1.5
  Corn fresh (sweet) (K+CWHR)                          0.1
  Corn grain                                           0.1
  Cottonseed                                           0.1
  Eggs                                                 0.02
  Flax, seed                                           3.0
  Flax, straw                                         10.0
  Goats fat                                            0.02
  Goats meat by-products                               0.02
  Goats, meat                                          0.02
  Hogs, fat                                            0.02
  Hogs, meat by-products                               0.02
  Hogs, meat                                           0.02
  Horses, fat                                          0.02
  Horses meat by-products                              0.02
  Horses meat                                          0.02
  Milk                                                 0.02
  Peas pods removed                                    0.2
  Peas forage                                          1.5
  Poultry fat                                          0.02
  Poultry meat by-products                             0.02
  Poultry, meat                                        0.02
  Pumpkins                                             0.1
  Sheep. fat                                           0.02
  Sheep, meat by-products                              0.02
  Sheep, meat                                          0.02
  Sorghum, fodder                                      5.0
  Sorghum, forage                                      5.0
  Sorghum, grain (milo)                                0.25
- International tolerances:  Presently, there are no tolerances for
  residues of propachlor in Canada, Mexico, or in the Codex
  Alimentarius.
Problems Known to have Occurred with Use of Chemical
- The Pesticide Incident Monitoring System (PIMS) did not show any
  incidents involving uses of propachlor.
Summary Science Statement
- Propachlor is not acutely toxic by the oral and dermal routes of
  exposure.  However, primary eye irritation data on propachlor show
  corrosivity and corneal opacity not reversible within seven days in
  rabbits.  If propachlor came in contact with the eyes, it could
  cause irreversible eye injury to man.  Propachlor may also induce
  photosensitivity or photosensitization due to the presence of
  aniline in its composition.
- Propachlor is highly toxic to coldwater fish, highly to moderately
  toxic to warmwater fish, and highly to moderately toxic to fresh-
  water invertebrates.
            4.  SUMMARY OF REGULATORY POSITION AND RATIONALE
- Based on the review and evaluation of all available data and other
  relevant information on propachlor, the Agency has made the following
  determinations:
  - The available data are insufficient to show that any of the risk
    criteria listed in 162.11(a) of Title 40 of the U.S. Code of Federal
    Regulations have been met or exceeded for the uses of propachlor at
    the present time.
  - There are no valid long-term chronic toxicity data for propachlor.
    Studies indicate that propachlor is structurally similar to
    alachlor, which is oncogenic in laboratory rats and mice.  Data on
    propachlor show that it is corrosive to the eye, with corneal
    opacity irreversible after seven days.  Further, propachlor has been
    shown to be highly toxic to coldwater fish, highly to moderately
    toxic to warmwater fish, and highly to moderately toxic to fresh-
    water invertebrates.  In addition to the extensive subchronic and
    chronic toxicity data gaps, there are also residue chemistry and
    environmental fate data gaps.  Because the existing data are
    insufficient to show that any of the risk criteria have been met or
    exceeded, the Agency is not initiating a Special Review at this
    time.
  - The most appropriate regulatory action is to move quickly to fill
    the data gaps.  Then the Agency will make a determination as to the
    future registerability of the affected uses.
- Specific label warning statements:
  - Hazard information:  DANGER.  Corrosive, causes irreversible eye
    damage.  Harmful if swallowed or absorbed.  Do not get in eyes or
    on clothing.  Wear goggles, face shield, or safety glasses.
  - Protective clothing requirements:
    - Required clothing and equipment for mixing/loading and applying
      propachlor:
    - One-piece coveralls which have long sleeves and long pants
      constructed of laminated fabric as specified in the USDA/EPA
      Guide for Commercial Applicators.
    - Goggles, face shield, or safety glasses.
    - Liquid-proof hat such as a plastic hard hat with a plastic
      sweatband.
    - Heavy-duty liquid-proof rubber (neoprene) work gloves.
  - Any article worn while handling propachlor must be cleaned before
    reusing.  Clothing which has been drenched or has otherwise
    absorbed concentrated pesticide from any significant spill must be
    disposed of in a sanitary landfill, by incineration, or, if
    allowed by state and local authorities, by burning.  If burned,
    stay out of smoke.
  - Instead of clothing and equipment specific above, the applicator
    can use an enclosed tractor cab which provides a filtered air
    supply (as described by Taschenberg and Bourke, 1975).
- Prohibition on aerial application:  Do not apply with aerial
  equipment.
- Environmental hazard statements:
  - All manufacturing-use products (MUPs) intended for formulation
    into end-use products (EUPs) must bear the following statement:
    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.
  - The following environmental hazard statement must appear on all
    granular EUPs:  This pesticide is toxic to fish.  Do not apply
    directly to water.  Runoff from treated areas may be hazardous to
    aquatic organisms in neighboring areas.  Do not contaminate water
    by cleaning of equipment or disposal of wastes.  In case of
    spills, collect for use or properly dispose of granules.
  - The following environmental hazard statement must appear on all
    non-granular EUPs:  This pesticide is toxic to fish.  Do not
    apply directly to water.  Drift and runoff from treated areas may
    be hazardous to aquatic organisms in neighboring areas.  Do not
    contaminate water by cleaning of equipment or disposal of wastes.
    In case of spills, collect for proper disposal.
- Registrants must revise the labeling of MUPs and EUPs as specified
  in the Required Labeling section on products released for shipment
  as of September 1, 1985.
                     5.  SUMMARY OF MAJOR DATA GAPS
- The following toxicological studies are required:
  - An acute inhalation toxicity study in the rat.
  - A dermal sensitization study in the rabbit.*
  - A 90-day dermal study in the rabbit.
  - A 90-day inhalation study in the rat.
  - A 90-day feeding study in rodent and non-rodent.
  - A chronic toxicity study in rat and in dog is required by February,
    1987.
  - An oncogenicity study in rat and in mouse is required by February,
    1987.
  - A teratology study in the rabbit is required by April, 1985.**
  - A 2-generation reproduction study in the rat is required by
    February, 1987.
  - The following mutagenicity data are required by January, 1987:
    - In vitro mammalian cell point mutation [L5178Y (TK); or
      CHO(HGPRT) or V79(HGPRT)].
    - In vitro cytogenetic damage:  both chromosomal aberration and
      SCE (in CHD cells, or human lymphocytes, or other rodent/human
      cell line/strains).
    - In vitro/in vivo primary hepatocyte repair for UDS testing
      both in vivo and in vitro exposure of cells to alachlor.
    - In vivo cytogenetics test for chromosomal aberrations using
      bone marrow preparations of rats.
    - Dominant lethal test in rats or mice.
- A domestic animal safety study is required.
NOTE:  *A dermal sensitization study in guinea pigs (Acc. 255806,
December, 1984) has been received by the Agency, and it is being
reviewed.
       **A teratology study in rabbits (Acc. 255758,  November, 1984)
has been received by the Agency, and it is being reviewed.
- The following environmental fate data are required:
  - A hydrolysis/degradation study is required by July, 1985.
  - A photodegradation study in water is required by July, 1985.
  - A photodegradation study on Soil is required by July. 1985.
  - An additional metabolism test in aerobic soil is required by July,
    1986.
  - Additional data on mobility of degradates from aged propachlor are
    required by April, 1985.
  - Soil dissipation data are required by July, 1987.
  - An accumulation study in rotational crops (confined).
  - A flow-through/accumulation test in fish.
- The following ecological effects data are required:  An acute fresh-
  water fish toxicity test on a coldwater species may be required
  pending review of environmental fate data which will be submitted in
  1985, 1986, and 1987.
- The following product chemistry data are required:
  - A complete statement of composition.
  - A preliminary analysis.
  - A certification of limits.
  - Analytical methods for enforcement of limits.
  - The octanol/water partition coefficient.
  - The pH of the TGAI.
- The following residue chemistry data are required:
  - 14C ring labeled data with corn and sorghum up to the seed stage.
  - 14C ring labeled data on the nature of the residue in ruminants.
  - Metabolism data on propachlor in poultry.
  - Metabolism data on propachlor in non-ruminants (name/species).
  - A radiocarbon study in which samples are analyzed simultaneously by
    cold and hot analytical methodology for N-isopropylaniline moiety,
    including a comparison of the results.  (If other metabolites are
    found in or on plants and in animals, then an enforcement method to
    determine these residues would be required.)
  - Storage stability data on propachlor residues in plant and animal
    samples.
  - Residue data on the metabolites of propachlor in plants.
  - Residue data on the metabolites of propachlor in animals.
  - Residue data on the metabolites of propachlor in poultry and eggs.
  - A cow feeding study on propachlor.
  - Geographical representation of residue data are not adequate;
    therefore, additional field residue data are required.
  - Residue data on corn forage to support the application rate of 6 lb.
    a.i./A on soils with an organic matter content of more than 3%.
  - Additional residue data for corn fodder using the 20% granular
    formulation.
  - Residue data for corn grain using the 20% granular and 42% flowable
    liquid formulations.
  - Residue data for sweet corn using the flowable liquid concentrate
    (FlC).
  - Residue data for the oil and milling fractions from the processing
    of treated corn or sorghum grain.
  - Residue data in cotton forage are required. (But an acceptable
    alternative would be a restriction against the grazing of livestock
    on cotton forage.)
  - Residue data in flax seed hulls which are fed to livestock.
  - Residue data for peas using the flowable liquid concentrate.
  - Residue data for pumpkins using the 90-day preharvest or postharvest
    interval (PHI).
  - The feeding rate data in the sheep study must be clarified.
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.