540/FS-89-065
            United States                Office of Pesticides and Toxic Substances
            Environmental Protection         Office of Pesticide Programs (H7508C)
            Agency                    Washington, DC 20460
EPA    Pesticide
             Fact   Sheet
             Name of Chemical:    TERBACIL
             Reason  for Issuance:  REGISTRATION STANDARD  (SRR)
             Date  Issued:   August 1989
             Fact Sheet Number:  206

  1.   DESCRIPTION  OF CHEMICAL
      Generic Name:  3-tert-butyl-5-chloro-6-methyluracil
      Common Name:  Terbacil
      Trade and Other Names:   5-chloro-3-(l,1-dimethylethyl)-6-
                             methyl-2,4(lH,3H)-pyrimidinedione,
                             Sinbar  , DuPont Herbicide 732,  and
                             Geonter.
      EPA Shaughnessy Codes:   012701
      Chemical Abstracts Service (CAS) Number: 5902-51-2
      Year of Initial Registration:  1966
      Pesticide Type: Herbicide
      Chemical Family: Uracils
      U.S. Producers:  E.I. duPont de Nemours Company, Inc.
  2.   USE PATTERNS AND FORMULATIONS
      Application  sites: Terrestrial  food crops.
      Types and Methods of Application:  Tractor mounted spray
      boom to soil surfaces and small emerged weeds.  Aerial
      application.
      Application Rates:  0.4 tc 8.0  Ib active ingredient per  acre
      Annual Usage:  290,000 - 610,000 pouncs
      Types of Formulation:  Wettable Tr Mvde.:

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3.    SCIENCE FINDINGS

     Chemical Characteristics of the Technical Matericil

     Physical State:  Crystalline solid

     Color:   White

     Odor:   None

     Molecular Weight and Formula:   216.7

     Boiling Point:   Terbacil is a  solid at room temperature

     Vapor  Pressure:  4.7 x 10"7 mm  Hg at 29.5°C

     Density:  1.34

     Solubility in various solvents:  Water,  xylene,  and
                                      dimethylformamide

     Toxicology Characteristics

     -Acute Oral:  1082 mg/kg (rat)  Toxicity Category III
     -Acute Dermal:  >5000 mg/kg (rabbit) Toxicity Category III
     -Primary Dermal Irritation: No irritation demonstrated
     -Primary Eye Irritation:  slight eye irritation (conjunctiva)
     -Dermal Sensitization:  Not a  dermal sensitizer
     -Acute Inhalation: >4.4 mg/liter/4 hours (Toxicity Category III)
     -Subchronic dermal (21-day):  > 5000 mg/kg.  No toxic signs.
     -Subchronic Oral (90-day): No  Observed Effect Level (NOEL) of
      5 mg/kg/day.
     -Chronic Oral dog (2-year): NOEL of 1.25 mg/kg/day.
     -Oncogenicity:  Data Gap.
     -Teratogenicity (rat): Not teratogenic.  Maternal NOEL was 62.5
      mg/kg/day. Teratogenicity NOEL > 250 mg/kg/day.
     -Teratogenicity (rabbit):  Not  teratogenic.  Maternal and embryo-
      toxicity NOEL was 200 mg/kg/day. Teratogenicity NOEL was 600
      600 mg/kg/day  (highest dose tested).
     -Reproduction:  No observed effects with a NOEL of 62.5 mg/kg/day
      (highest dose  tested).
     -Mutagenicity:   Non-mutagenic  in assays tested.
     -Metabolism:  Data Gap.

     -Major route of exposure:   Dermal

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Physiological and Biochemical Characteristics

-Mechanism of Pesticidal Action:  Stops photosynthesis
-Metabolism and Persistence in Plants and Animals:  The
 available data are not adequate to assess the nature of
 terbacil in plants or in animals.

Environmental Characteristics

-Terbacil is stable to hydrolysis and photodegrades slowly in
 water.
-It has a potential to contaminate ground water particularly in
 areas with sandy soil surfaces.
-It leaches slower in fine textured soils and also in soils
 having higher organic contents.
-It does not accumulate to significant levels in bluegill
 sunfish.
-Residues resulting from multiple applications of terbacil
 persisted for 2 years following the final application.
-Preliminary data indicate that terbacil is extremely persistent
 with half-lives of 520 days aerobically and 178 days
 anaerobically.

Ecological Characteristics

-Avian acute toxicity:
     >2250 mg/kg (Quail).  Practically Non-toxic.
-Avian dietary toxicity:
     >5000 ppm (Mallard duck,). Practically Non-toxic.
-Freshwater fish acute toxicity:
    102.9 ppm  (Bluegill sunfish)  Practically Non toxic.
     46.2 ppm  (Rainbow trout)     Slightly Toxic
-Marine fish acute toxicity:  Data Gap
-Freshwater invertebrate toxicity:
     65 ppm (Daphnia). Slightly toxic.
-Marine invertebrate toxicity:
     >4.9 ppm  (Oyster). Moderately toxic
     49 ppm (Shrimp).   Slightly toxic

TOLERANCE ASSESSMENT

-Tolerances have been established for residues of Terbacil in a
 variety of raw agricultural commodities (Refer to 40 CFR
 180.209 for listing of tolerances). Terbacil's tolerances have
 been reassessed using the Tolerance Assessment System
 (TAS). The TAS chronic exposure analysis estimates average
 daily exposure for the overall U.S. population and each of
 the 22 populations subgroups and compares these estimates
 to the acceptable daily intake (ADI) calculated for
 terbacil.

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     The Theoretical Maximum Residue Contribution (TMRC)  for the
     overall U.S.  population is estimated to be 0.001594
     mg/kg/day,  which occupies approximately 12% of the ADI.  The
     two most highly exposed subgroups are non-nursing infants,
     less than 1 year old (TMRC= 0.008122 mg/kg/day or 62% of the
     ADI),  and children , 1- 6 years of age (TMRC= 0.004361
               or 34% of the ADI) .
4.    Summary of Regulatory Positions

     This review of terbacil is the second intensive evaluation of the
     compound.   In its original Registration Standard,  issued in
     1982 ,  the Agency summarized the available data supporting
     the registration of terbacil and concluded that additional
     data were needed to fully evaluate the pesticide.

     The Agency has since received and reviewed the data and has
     revised its scientific and regulatory conclusions  relative
     to these data.

     o Terbacil will not be placed in Special Review at this time.
     o The Agency will impose a ground water contamination advisory
     statement to reduce point source contamination.
     o The Agency is requiring the following testing on all terbacil
     end-use products: acute oral, acute dermal,  primary eye,
     primary skin, dermal sensitization, and acute inhalation if
     appropriate.
     o The Agency will not establish a reentry interval for terbacil
     beyond the minimum reentry interval (sprays have dried,
     dusts have settled and vapors have dispersed) .
     o The Agency will require updated worker safety and protective
     equipment statements for end-use products containing terbacil.
     o The Agency is requiring a rotational crop statement on all
     terbacil labels which may involve rotation to crops other
     than those currently registered (refer to section IV. D for
     specific wording) .  In addition residue data are required
     for representative crops from any crop group which could be
     rotated from alfalfa, sainfoin, and mint.
     o Existing Tolerances for Terbacil per se should be amended to
     include metabolites A,B, and C, as specified in 40 CFR
     180.209 (b) .
     o The Agency will revoke tolerances associated with the
     commodities sainfoin (hay) , sainfoin (forage) , and pears.
     o The Agency will revise the tolerance for residues in or on
     peaches to 0.2 ppm for combined residues of terbacil and its
     metabolites.

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o The Agency will impose a label restrictions against the feeding
and grazing of sugarcane forage and spent hay to livestock
or require the development and submission of data in support
of tolerances for residues in or on sugarcane forage and
spent hay.
o The Agency has determined that grasses grown for seed is a food
use.  Therefore, data depicting residues of terbacil in or
on members of the grass forage, fodder and hay group are
required.
o The Agency will not propose group tolerances for terbacil.
o The Agency will not grant any significant new food or feed uses
for terbacil until the required residue chemistry and
toxicology studies have been submitted and reviewed.
o The Agency has identified certain data that will receive
priority review when submitted;

Section 158.340 Toxicology
83-1 Chronic Oral Feeding (Rat)
83-2 Oncogenicity (Rat and Mouse)

Section 158.290 Environmental Fate
162-1 Aerobic Soil Metabolism
162-2 Anaerobic Soil Metabolism
163-1 Leaching Adsorption/Desorption
164-5 Soil, Long Term (field)

Section 158.490 Wildlife and Aquatic Organisms
72-3 Estuarine and Marine Testing (Fish)
122- Tier I Nontarget Area Phytotoxicity

Section 158.240 Residue Chemistry
171-4 Metabolism in Plants & Livestock

Required Unique Labeling

A. Groundwater Advisory Statements
B. Environmental Hazards Statement
D. Reentry Statement
E. Feeding and/or Grazing Restrictions
F. Rotational Crop Statement
Summary of Major Data Gaps

Toxicology
Environmental Fate/Exposure
Ecological Effects
Residue Chemistry
Product Chemistry
Timeframe Ranges

12-48 Months
12-48 Months
   24 Months
24-48 Months
12-24 Months

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  7.   CONTACT  PERSONS AT EPA
      Product Specific  Inquiries:
      Robert J. Taylor
      Product Manager  (25)
      Fungicide Herbicide  Branch
      Registration  Division  (H-7505C)
      Office of Pesticide  Programs
      Environmental Protection Agency
      401 M Street,  S.  W.
      Washington, D. C.  20460

      Office location and  telephone  number:
      Room 245, Crystal Mall  #2
      1921 Jefferson Davis Highway
      Arlington, VA 22202
       (703) 557-1800

      Reregistration Document Inquiries;
      Donna M. Williams
      Review Manager
      Reregistration Branch
      Special Review and Reregistration  Division  (H-7508C)
      Environmental Protection Agency
      401 M Street,  S.  W.
      Washington, D. C.  20460

      Office location and  telephone  number:
      Room 1124, Crystal Mall #2
      1921 Jefferson Davis Highway
      Arlington, VA 22202
       (703) 557-0639
DISCLAIMER:   The information in this Pesticide
Fact Sheet is a summary only and is not to be used
to satisfy data requirements for pesticide
registration and reregistration.  The complete
Registration Standard for the pesticide may be
obtained from the National Technical Information
Service.  Contact the Review Manager listed above
for further information.

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