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Simazine (Princep) - Herbicide Profile 2/85

                                      simazine
      CHEMICAL name:      2-chloro-4,6-bis(ethylamino)-s-triazine (56)
      TRADE name(S):      Princep, Aquazine (58)
      FORMULATION(S):     Wettable powder (80%0, water dispersible granule
                          (90%; Caliber 90), liquifieds (4L), and granular
                          (4G).  Aquazine for algae control in ponds (56).
      TYPE:               Triazine herbicide
      BASIC PRODUCER(S):  Ciba-Geigy Corp.
                          Agricultural Divison
                          P.O. Box 11422
                          Greensboro, NC 27409
      STATUS:             General use
      PRINCIPAL USES:  Used for the control of most annual grasses and
      broadleaf weeds in corn, established alfalfa, established
      bermudagrass, cherries, peaches, citrus, caneberries, cranberries,
      grapes, apples, pears, certain nuts, asparagus, certain
      ornamental and tree nursery stock, and in turfgrass sod production.  At
      higher rates, it is used for nonselective weed control in industrial
      areas (56).  Simazine is also used for selective control of algae and
      submerged weeds in ponds.  It is approved for algae control in swimming
      pools, large aquaria, ornamental fish ponds, fountains, and
      recirculating water cooling towers (58).
                                   I.  EFFICACY
           Simazine applied preemergence to the weeds at dosage rates of 1 to
      4 lbs. active ingredient per acre has controlled the following:
      barnyardgrass              hempnettle               redroot pigweed
      beggar-ticks               jimsonweed               Shepherdspurse
      carpetweed                 knotwood                 smartweed
      catchfly                   kochia                   sowthistle, common
      chickweed, common          lambsquarters            stinkgrass
      cocklebur                  nightshade               stinkweed
      corn spurry                panicum, fall            velvetleaf
      crabgrass                  plantain                 water hemp
      downy bromegrass           puncture vine            white cockle
      Florida pusley             purslane                 wild buckwheat
      foxtail, green             quackgrass               wild mustard
      foxtail, yellow            quickweed                wild oats
      goosegrass                 ragweed, common          witchgrass
      groundsel                  ragweed, giant           yellow rocket (24f)
      Weeds controlled in alfalfa (for North and South Dakota, Minnesota,
      Wisconsin, Nebraska, Kansas, Iowa, Michigan, and New York):
      Downy brome (cheatgrass), henbit, wild mustard, chickweed, wild oats,
      Knawel (German moss), alyssum, pepper grass, tansey mustard, pigweed,
      speedwell, and seedlings of yellow rocket, white cockle, fanweed
      (pennycress), dandelion, Russian thistle, shepherdspurse, and kochia.
      Weeds not controlled:
           Princep will not control dodder and established perennial and
      biennial weeds such as dandelion, white cockle, quackgrass, cinquefoil,
      wild carrot, dock, and certain other weeds (24g).
                             II.  PHYSICAL PROPERTIES
      MOLECULAR FORMULA:  C7 H12 Cl N5 (62)
      MOLECULAR WEIGHT:   201.7 (62)
      PHYSICAL STATE:     Colorless crystalline powder (pure compound) (62)
      MELTING POINT:      225-227 C (decomp.) (pure compound) (62)
      VAPOR PRESSURE:     810 nPa at 20 C (pure compound) (62)
      SOLUBILITY:         5 mg/l water at 20 C (pure compound) (62)
                          III.  HEALTH HAZARD INFORMATION
      OSHA STANDARD:  NA
      NIOSH RECOMMENDED LIMIT:  NA
      ACGIH RECOMMENDED LIMIT:  NA
      TOXICOLOGY
           A.  ACUTE TOXICITY
               DERMAL:  LD50 = >10,200 mg/kg (rabbit, Princep 80W);
                          minimally irritating to the skin.  Studies with
                          rabbits have shown that irritation to the skin was
                          barely perceptible 24 hrs. after exposure
                          (Princep 80W) (24e).
                        LD50 = >3100 mg/kg (rat), non-irritant to skin
                          of rabbits (62).
               ORAL:    LD50 = >5000 mg tech./kg (rat) (62)
                        LD50 = >15,380 mg/kg (rat, Princep 80W); in studies
                          with rats, no animals died from a single swallowed
                          amount of 15,380 mg/kg (Princep 80W) (24e).
               INHALATION:  LC50 = >1.0 mg/l air - 4 hours (rat); no higher
                            concentrations were possible with this material;
                            no animals died during this study (Princep 80W)
                            (24e).
               EYES:  Slightly irritating on contact.  Studies with
                      rabbits have shown that some redness and swelling of
                      the eyelids occurred (Princep 80W) (24e).
           B.  SUBACUTE AND CHRONIC TOXICITY:

           In 2-yr. feeding trials NEL was: for rats 100 mg/kg diet (7 mg/kg
      daily); for dogs 150 mg/kg diet (5 mg/kg daily) (62).
                        IV.  ENVIRONMENTAL  CONSIDERATIONS
           Simazine is more highly adsorbed in muck or high clay soils than
      in low organic or low clay content soils.  The downward movement or
      vertical leaching of simazine occurs at a rather low rate of speed,
      probably due to the low water solubility of the compound and also
      adsorption to the soil particles.  Tests indicate that several months
      after application the greatest amount of simazine remaining in the soil
      is contained in the area near the soil surface.  The compound has
      little if any lateral movement in soils (24f).
           Microbial breakdown is one of several processes involved in the
      degradation of simazine.  In soils, microbial activity possibly
      accounts for decomposition of a significant amount of simazine.  Under
      normal climatic conditions, loss of simazine from soil by
      photodecomposition and/or volatilization is considered insignificant
      (58).
      Approximate Residual Period:  In regard to the soil residual activity
      of simazine, results to date suggest that most rotational crops can be
      planted and grown one year after an application of simazine at the
      dosage rate recommended for the soil type; tillage practices such as
      plowing and harrowing will reduce the possibility of adverse soil
      residual effects.  Adverse soil residual activity has been experienced
      mainly in areas of extremely low rainfall or where rainfall has been
      practically nonexistent following application of the compound.  Oats
      appear to be one of the most susceptible crops to the residual activity
      of Simazine (24f).
                      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:
           Some triazines are mildly irritating to skin,
      eyes, and upper respiratory tract.  Systemic toxicity is unlikely
      unless very large amounts have been ingested (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).
           INHALATION:  Remove from contaminated atmosphere.  If symptoms
      appear or person is unconscious, get medical attention (Princep 80W)
      (24e).
           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
      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:  Not a combustible product.  No hazardous decomposition
      products.  As in any fire, prevent human exposure to fire, smoke, fumes
      or products of combustion.  Evacuate nonessential personnel from the
      area.  Firefighters should wear impervious clothing such as gloves,
      hoods, suits and rubber boots.  Use of contaminated buildings, area and
      equipment must be prevented until they are properly decontaminated
      (Princep 80W) (24e).
      EXTINGUISHER TYPE:  Use standard organic chemical firefighting
      techniques in extinguishing fires involving this material - use water,
      dry chemicals, foam or carbon dioxide (Princep 80W) (24e).
                                VII.  COMPATIBILITY
           Compatible with most other pesticides and fertilizers when used at
      normal rates.  Noncorrosive under normal use conditions (58).
                            VIII.  PROTECTIVE MEASURES
      STORAGE AND HANDLING:  Keep this material out of the reach of children.
      Containers must be stored in a cool, dry, well ventilated area.  Store
      away from foodstuffs.  All food must be kept in a separate area away
      from the storage/use location.  Eating, drinking and smoking should be
      prevented in areas where there is a potential for exposure to this
      material (Princep 80W) (24e).
      PROTECTIVE CLOTHING:   Skin contact should be prevented through the use
      of rubber gloves and clothing consistent with good pesticide handling
      practice.  Eye contact should be avoided through the use of chemical
      safety glasses or goggles (Princep 80W) (24e).
                       IX.  PROCEDURES FOR SPILLS AND LEAKS
                     IN CASE OF EMERGENCY, CALL, DAY OR NIGHT
                                  (800) 424-9300
                      PESTICIDE TEAM SAFETY NETWORK/CHEMTREC
           Make sure all personnel involved in spill cleanup follow good
      industrial hygiene practices.
           Small spills can be handled routinely.  Sweep up the material and
      place in an appropriate chemical waste container.  Seal container and
      dispose of in an approved landfill.  Wash the spill area with a strong
      detergent and water.  Flush the spill area with water to remove any
      residue.
           Do not reuse container.  Destroy by burying in a safe place.
      Disposal of material, spill residues, wash water, and containers must
      be by methods consistent with local, state and federal health and
      environmental regulations (Princep 80W) (24e).
                               X.  LITERATURE CITED
      24e. Ciba-Geigy Corporation, Agricultural Division.  1982.  Safety
               data sheet:  Princep 80W.  Greensboro, NC.
      24f. Geigy Chemical Corporation.  1960.  Herbicide technical
               bulletin no. 60-1:  simazine herbicides for agricultural
               use.  Ardsley, NY.
      24g. Ciba-Geigy Corporation.  1973.  Information sheet:  Princep
               for weed control in alfalfa.  Greensboro, NC.
      25.  Morgan, D.P.  1982.  Recognition and management of pesticide
               poisonings, 3rd ed.  U.S. Environmental Protection Agency,
               Washington, DC.  120 pp.
      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.
      2/8/85