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siduron (Tupersan) Herbicide Profile 2/85

                                      siduron
      CHEMICAL NAME:      1-(2-Methylcyclohexyl)-3-phenylurea (56)
      TRADE NAME(S):      Tupersan (56)
      FORMULATION(S):     Wettable powder 50% for spray application; 70%
                          powder for manufacturing use.  Various granulars and
                          mixtures with fertilizer and/or insecticides
                          available from formulators (56).
      TYPE:               Substituted urea herbicide
      BASIC PRODUCER(S):  E.I. duPont de Nemours and Co., Inc.
                          Biochemicals Dept.
                          1007 Market St.
                          Wilmington, DE 19898
      STATUS:             General use
      PRINCIPAL USES:  Selectively controls certain germinating annual weed
      grasses such as crabgrass (smooth and hairy), foxtail and barnyardgrass,
      in newly seeded or established plantings of bluegrass, fescue, redtop,
      smooth brome, perennial ryegrass, orchardgrass, zoysia, and the following
      strains of bentgrass: PennCross, Seaside, Highland, Astoria, Nimisila,
      C-1, C-7, and C-19.  Should not be used on other bentgrass strains nor
      on bermudagrass (58).
      APPLICATION METHOD(S):  Applied as a preemergence treatment to bare soil
      as a final operation following spring seeding, or to new fall seedings
      or established turf in the spring just before expected emergence of
      annual weed grasses (58).
                                   I.  EFFICACY
           To be developed.
                             II.  PHYSICAL PROPERTIES
      MOLECULAR FORMULA:  C14 H20 N2 O (62)
      MOLECULAR WEIGHT:   232.3 (62)
      PHYSICAL STATE:     Colorless crystals (pure compound) (62);
                          light gray powder (Tupersan Weed Killer) (31o).
      ODOR:               Odorless (active ingredient) (31n)
      MELTING POINT:      133-138 C (pure compound) (62)
      VAPOR PRESSURE:     Negligible (Tupersan Weed Killer) (31o); <8 x 10-4
                          mmHg at 100 C (pure compound) (58).
      SOLUBILITY:         18 mg/l water at 25 C (pure compound) (62)
                          III.  HEALTH HAZARD INFORMATION
      OSHA STANDARD:  NA
      NIOSH RECOMMENDED LIMIT:  NA
      ACGIH RECOMMENDED LIMIT:  NA
      TOXICOLOGY
           A.  ACUTE TOXICITY
               DERMAL:  The maximum feasible dose (5500 mg/kg) applied to
      intact or abraded skin of rabbits caused no  sign of toxicity (62).
      A 10% suspension in dimethyl phthalate was not irritating to
      guinea pig skin.  A 25% suspension was mildly irritating, while a 40%
      suspension was moderately to strongly irritating.  It did not produce
      an allergic contact dermatitis (31n).
               ORAL:    LD50 = >7500 mg/kg (rat) (62)
           B.  SUBACUTE AND CHRONIC TOXICITY:
           In two-year feeding studies, the no-observable effect level for
      rats was 500 ppm; for dogs 2500 ppm (31n).
                        IV.  ENVIRONMENTAL  CONSIDERATIONS
           TLM (48 hours) for carp is 18 ppm
           TLM (48 hours) for Japanese goldfish is 10-40 ppm
           TLM (48 hours) for loach is 10-40 ppm
           TLM (48 hours) for tadpole is 10-40 ppm
           TLM (72 hours) for crawfish is >40 ppm
           TLM (3 hours) for water flea is >40 ppm
           LC50 (8 day dietary) for both mallard duckling and bobwhite quail
      greater than 10,000 ppm (31n).
           Siduron resists leaching, remains in the top layer of soil, and
      degrades at a moderate rate.  Half-life in soil is 4 to 5 months (31n).
           Adsorption of siduron increases as clay content and/or organic
      matter content of soil increases; clays of high exchange capacity
      adsorb more than those of low exchange capacity.  The amount adsorbed
      on Keyport silt loam in equilibrium with 1 ppm in soil solution at 22.5
      C is 2.5 ppm.  Siduron is very resistant to leaching.  Movement is least
      in soils high in clay and/or organic matter; greatest in sand.
           Microbes are the primary factor in the disappearence from soils.
      It has been demonstrated that certain soil microorganisms can
      utilize siduron as their sole carbon source.  Two bacterial and a
      single fungal species capable of metabolizing siduron have been
      isolated.  The bacterial species were tentatively identified as
      belonging to genus Pseudomonas, while the fungus was identified as
      belonging to the group of Fungi Imperfecti.
           After exposure in a thin film to full sunlight for 56 days,
      siduron caused injury to germinating crabgrass identical with that
      caused by a nonirradiated check sample.  Chemical analysis also
      verified that siduron was not decomposed by sunlight.
           In studies over a 3-year period in a temperate climate under an
      annual rainfall of about 45 inches, there has been no evidence of
      residual chemical in the soil after 1 year, even with applications much
      in excess of those required for weed control (58).
                      V.  EMERGENCY AND FIRST AID PROCEDURES
           The chemical information provided below has been condensed
      from original source documents, primarily from "Recognition and
      Management of Pesticide Poisonings", 3rd ed. by Donald P.  Morgan,
      which have been footnoted.  This information has been provided in
      this form for your convenience and general guidance only.  In
      specific cases, further consultation and reference may be required
      and is recommended.  This information is not intended as a sub-
      stitute for a more exhaustive review of the literature nor for the
      judgement of a physician or other trained professional.
           If poisoning is suspected, do not wait for symptoms to develop.
      Contact a physician, the nearest hospital, or the nearest Poison
      Control Center.
      KNOWN OR SUSPECTED ADVERSE EFFECTS:  Many substituted ureas are
      moderately irritating to skin, eyes, and mucous membranes (25).
           SKIN CONTACT:  Wash contaminated skin with soap and water (25).
           INGESTION:  Ingestions of small amounts (less than 10 mg/kg
      body weight) occurring less than an hour before treatment, are probably
      best treated by:  Syrup of Ipecac, followed by 1-2 glasses of water.
      Dose for adults and children over 12 years:  30 ml.  Dose for children
      under 12 years:  15 ml (25).
           EYE CONTACT:  Flush contaminated eyes with copious amounts of
      fresh water for 15 minutes (25).
      NOTES TO PHYSICIAN:
      INGESTIONS of LARGE amounts (more than 10 mg/kg) occurring less than an
      hour before treatment, should probably be treated by gastric lavage:
      A.   INTUBATE stomach and ASPIRATE contents.
      B.   LAVAGE stomach with slurry of ACTIVATED CHARCOAL IN 0.9% saline.
           Leave 30-50 gm activated charcoal in the stomach before
           withdrawing tube.
      C.   SODIUM SULFATE, 0.25 gm/kg in tap water, as a cathartic.
           CAUTION:  Hydrocarbons (kerosene, petroleum distillates) are
                     included in some formulations of these chemicals.
                     Ingestion of very LARGE AMOUNTS may cause CNS
                     depression.  In this case, IPECAC IS CONTRAINDICATED.
                     Also, gastric intubation incurs a risk of HYDROCARBON
                     PNEUMONITIS.  For this reason observe the following
                     precautions:
                     (1)  If the victim is unconscious or obtunded and
                          facilities are at hand, insert an ENDOTRACHEAL TUBE
                          (cuffed, if available) prior to gastric intubation.
                     (2)  Keep victim's HEAD BELOW LEVEL OF STOMACH during
                          intubation and lavage (Trendelenburg, or left
                          lateral decubitus, with head of table tipped
                          downward).  Keep victim's head turned to the left.
                     (3)  ASPIRATE PHARYNX as regularly as possible to remove
                          gagged or vomited stomach contents.
      INGESTIONS occurring MORE THAN an HOUR before treatment are probably
      best treated only by ACTIVATED CHARCOAL, 30-50 gm, and SODIUM or
      MAGNESIUM SULFATE, 0.25 gm/kg, as described above.
      There are no specific antidotes for these chemicals.  Because
      manifestations of toxicity do occasionally occur in peculiarly
      predisposed individuals, MAINTAIN CONTACT with victim for at least 72
      hours so that unexpected adverse effects can be treated promptly (25).
                        VI.  FIRE AND EXPLOSION INFORMATION
      GENERAL:  May be ignited by heat or open flame.  Fine dust dispersed in
      air (particularly in confined spaces) may ignite if exposed to high
      temperature ignition source.  These conditions are unlikely to occur in
      normal, outdoor use of this product (Tupersan Weed Killer) (31o).
      EXTINGUISHER TYPE:  On a small fire use dry chemical, CO2, foam or
      water spray.  If area is heavily exposed to fire and if conditions
      permit, let fire burn itself out since water may increase the
      contamination hazard.  If conditions do not permit, extinguish with
      water spray.  If conditions permit, cool containers with water if
      exposed to fire.  Wear self-contained breathing apparatus (31o).
                                VII.  COMPATIBILITY
           To be developed.
                            VIII.  PROTECTIVE MEASURES
      STORAGE AND HANDLING:  Store in a cool, dry place.  Do not contaminate
      water, food, or feed by storage or disposal.  Do not reuse container.
      Bury empty container or product that cannot be used in a safe place
      away from water supplies or dispose of by alternative procedures
      recommended by federal, state, or local authorities.  Open dumping is
      prohibited.  Avoid contact with skin, eyes, and clothing (56).
                       IX.  PROCEDURES FOR SPILLS AND LEAKS
                     IN CASE OF EMERGENCY, CALL, DAY OR NIGHT
                                  (800) 424-9300
                      PESTICIDE TEAM SAFETY NETWORK/CHEMTREC
           Clean up promptly.  Do not flush with water, pick up dry by
      sweeping or other effective means (Tupersan Weed Killer) (31o).
                               X.  LITERATURE CITED
      25.  Morgan, D.P.  1982.  Recognition and management of pesticide
               poisonings, 3rd ed.  U.S. Environmental Protection Agency,
               Washington, DC.  120 pp.
      31n. E. I. du Pont de Nemours and Co., Inc., Biochemicals Department.
               1979.  Technical data sheet:  siduron.  Wilmington, DE.
      31o. E. I. du Pont de Nemours and Co., Inc., Biochemicals Department.
               1977.  Material safety data sheet for Tupersan Weed Killer.
               Wilmington, DE.
      56.  Farm Chemicals Handbook, 70th ed.  1984.  R. T. Meister, G. L.
               Berg, C. Sine, S. Meister, and J. Poplyk, eds.  Meister
               Publishing Co., Willoughby, OH.
      58.  Weed Science Society of America, Herbicide Handbook Committee.
               1983.  Herbicide handbook of the weed science society of
               America, 5th ed.  Weed Science Society of America, Champaign,
               IL.  515 pp.
      62.  The Pesticide Manual:  A World Compendium, 7th ed.  1983.  C.R.
               Worthing, ed.  The British Crop Protection Council, Croydon,
               England.  695 pp.
      2/11/85