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Atrazine - Herbicide Profile 3/90

                                      atrazine
      CHEMICAL name:      2-chloro-4-ethylamino-6-isopropyl
                          amino-1,3,5-triazine (56)
      TRADE name(S):      AAtrex, Atranex (56)
      FORMULATION(S):  Atranex 50% and 80% wettable powder, 4 lb/gal

      flowable, 4L liquid.  Griffex 4L contains 4 pound flowable atrazine.
      Drexel Atrazine 4L, Drexel Atrazine 5L (contains 5 pounds of flowable
      atrazine/gal).  Drexel Atrazine 80W, and Drexel Atrazine 90 DF.  Farmco
      Atrazine flowable contains 500 g/l.  FBC Atrazine 80.  AAtrex:  80%
      wettable powder, 90% water dispersible granule, and liquified 4L (56).
      TYPE:               Triazine herbicide
      BASIC PRODUCER(S):  Shell Chemical Company
                          Agricultural Chemicals
                          One Shell Plaza
                          P.O. Box 3871
                          Houston, TX 77001
      STATUS:             Restricted-use as of 9/1/90
In late 1988, an atrazine management program was proposed to the
U.S. Environmental Protection Agency (EPA) by CIBA-GEIGY and
other registrants (producers) of the herbicide. We are pleased to tell
you that on January 26, 1990, the EPA announced the approval of
the program (with modifications).
Adoption of the management program means that several voluntary
exposure reduction measures will be adopted through changes in the
labels of all atrazine products registered by the EPA.
The resulting benefits will be: a reduction in potential exposure to
the herbicide by farmers and farm workers, a reduction in the
potential for infiltration of the herbicide into groundwater and
surface water, and a general reduction of the volume of the product
released into the environment.
Revised labeling is to be adopted by September 1, 1990, for atrazine
(along with all atrazine-containing products) to be sold for the 1991
use season. There is no requirement that stocks of products
remaining in channels of trade be relabeled. Atrazine-containing
products will become Restricted Use Pesticides (for use only by
certified applicators or persons under their direct supervision)
because of groundwater concerns. Exempt from this would be lawn
care products containing 2% atrazine or less in the formulation.
In announcing acceptance of the program, the EPA said "We
commend the technical manufacturers for their consideration of the
need to reduce exposure to atrazine. The label amendments designed
to reduce groundwater contamination may certainly reduce the
point-source problem. In addition, restriction to use by certified
applicators has the potential to reduce the risk of groundwater
contamination due to mixing/loading, application, and disposal."
The label revisions (in addition to the restricted use classification)
included the following:
1 Users must wear long-sleeve shirts and long pants (or equivalent),
chemical resistant gloves, and water-proofed boots. In addition,
persons involved in mixing and loading operations are required to
use chemical resistant rubber or neoprene gloves and a face shield or
goggles.
2 Groundwater contamination may be reduced by diking and flooring
of permanent liquid bulk storage sites with an impermeable
material.
3 This product may not be mixed/loaded or used within 50 feet of all
wells, including abandoned wells, drainage wells and sink holes.
4 Postemergence applications to corn and sorghum must be made
before the crops reach 12 inches in height.
5 The maximum application rate for corn and sorghum is three
pounds of active ingredient per acre per calendar year. Applications
of the product for quackgrass suppression in corn and sorghum are
restricted to spring application only. No fall applications are
permitted.
6 Applications for industrial weed control in noncrop areas may not
exceed a combined maximum of 10 pounds of active ingredient per
acre per calendar year.
7 Do not apply this product through any type of irrigation system.
The use changes adopted by the EPA are similar to those already
implemented under atrazine management programs in Wisconsin
and Iowa.
Also, the September will include the deletion of the uses on
pineapples, proso millet and rangeland.
revised labeling that will be sent to the EPA in
1990 will not only reflect the above revisions, but
will include the deletion of the uses on pineapples,
proso millet and rangeland.
      PRINCIPAL USES:  Atrazine is a widely used selective herbicide for
      control of broadleaf and grassy weeds in corn, sorghum,
      sugarcane, macadamia orchards, and turf grass sod.  It is
      used also in some areas for selective weed control in conifer
      reforestation and Christmas tree plantations as well as for nonselective
      control of vegetation in chemical fallow.  Atrazine also is used as a
      nonselective herbicide for vegetation control in noncrop land.  Sugar-
      beets, tobacco, oats, and many vegetable crops are very sensitive to
      atrazine (56).
      APPLICATION METHOD(S):  Depending upon the crop or intended use,
      atrazine sprays may be applied preplant, preemergence, or postemergence,
      but before weed seedlings are more than 3.8 cm (1.5 inches) high with
      few exceptions.  These exceptions include postemergent application for
      yellow nutsedge and Canada thistle control.  Preemergence use is
      generally the preferred method of application where it can be used.
      Under dry conditions, a shallow incorporation may increase the degree of
      weed control.  A single lay-by cultivation is sometimes useful to
      prevent relatively tolerant late season grasses from developing.  Aerial
      applications have been very successful, especially when wet weather
      prevents the use of ground equipment and in cases where rough terrain
      such as in conifer reforestation makes ground application impractical.
      A liquified formulation containing 0.48 kg/l (4 lb ai/gal) has been
      developed and is registered for weed control in conifers, corn,
      chemical fallow, rangeland, sugarcane, and sorghum.  A 90% water
      dispersible granular formulation has been registered bearing the full
      AAtrex label.  Future registration of the 4L formulation is planned on
      other crops.  Postemergent application of the wettable powder, the
      water dispersible granule or liquified formulation of atrazine is usually
      made in combination with a nonphytotoxic crop oil, crop oil concentrate
      or surfactant.  These additions enhance the uptake of atrazine and hence
      its activity (58).  May be applied to corn in solution with liquid
      nitrogen (8b).
                                   I.  EFFICACY
      Important Weeds Controlled:
           1. Crop areas - Barnyardgrass, mustards, chickweed, cocklebur,
      crabgrass, downy brome, foxtail, jimsonweed, lambsquarters, nutgrass,
      quackgrass, purslane, ragweed, velvetleaf, wild oats, and many others.
           2. Total vegetation control - The above weeds plus bindweed, dock,
      horsetail, milkweed, mullein, orchardgrass, plantain, quackgrass,
      leafy spurge, Canada thistle, and many others (8b).
           Moisture activates the chemical.  Usually considered more toxic
      than the other triazines.  Will not control Johnsongrass or Bermudagrass.
      Corn completely metabolizes it, not being injured.  Effective on most
      annual broadleaves for about three months.  Resembles simazine, but is
      faster acting under low rainfall conditions. Proven and used in all
      climates (8b).
                             II.  PHYSICAL PROPERTIES
      MOLECULAR FORMULA:  C8 H14 Cl N5 (62)
      MOLECULAR WEIGHT:   215.7 (62)
      PHYSICAL STATE:     Colorless powder (pure compound) (62)
      MELTING POINT:      175-177 C (pure compound) (62); 173-175 C (pure
                          chemical) (58).
      VAPOR PRESSURE:     3.0 x 10-7 mmHg at 20 C (pure compound) (58)
      SOLUBILITY:         30 mg/l water at 20 C (pure compound) (62)
                          III.  HEALTH HAZARD INFORMATION
      OSHA STANDARD:  NA
      NIOSH RECOMMENDED LIMIT:  NA
      ACGIH RECOMMENDED LIMIT:  TWA (Time Weighted Average) = 5 mg/m3 (15c)
      TOXICOLOGY
           A.  ACUTE TOXICITY
               DERMAL:  LD50 = >3100 mg/kg (rat, technical material);
                          >10,200 mg/kg, mild skin irritation (rabbit,
                          AAtrex 4L); 9300 mg/kg, minimal skin
                          irritation (rabbit, AAtrex 80W); >10,200
                          mg/kg, minimal skin irritation (rabbit, AAtrex
                          Nine-O) (56).
               ORAL:    LD50 = 1869 mg/kg (rat, technical material); 3800
                          mg/kg (rat, AAtrex 4L); 5100 mg/kg (rat, AAtrex
                          80W); 1600 mg/kg (rat, AAtrex Nine-O) (56).
               INHALATION:  LC50 = >6.8 mg/l for 4 hours (rat, AAtrex 4L);
                              >2 mg/l for 4 hours (rat, AAtrex 80W);
                              5.2 mg/l for 4 hours (rat, AAtrex Nine-O) (56).
               EYES:    Non-irritating (rabbit, technical material); mild
                        eye irritation (rabbit, AAtrex 4L, AAtrex 80W);
                        minimal eye irritation (rabbit, AAtrex Nine-O) (56).
           B.  SUBACUTE AND CHRONIC TOXICITY:
           No observable ill effects were detected in cattle, dogs, horses or
      rats fed a diet which included more than 25 ppm atrazine over extended
      periods (58).
           Two-year feeding studies in which male and female rats were given
      daily dosages of atrazine at various levels, showed no gross or
      microscopic signs of toxicity due to ingestion of levels as high as 100
      ppm in the total diet (58).
                        IV.  ENVIRONMENTAL  CONSIDERATIONS
      Behavior In or On Soils
      1.  Adsorption and leaching characteristics in basic soil types:
            Atrazine is more readily adsorbed on muck or clay soils than on
            soils of low clay and organic matter content.  The downward
            movement or leaching is limited by its adsorption to certain soil
            constituents.  Adsorption is not irreversible and desorption often
            occurs readily, depending on such factors as temperature,
            moisture, and pH.  Atrazine normally is not found below the upper
            foot of soil in detectable quantities, even after years of
            continuous use.
      2.  Microbial breakdown:  Microbial activity possibly accounts for
            decomposition of a significant portion of atrazine in the soil.  A
            range of soil microorganisms can utilize it as a source of energy
            and nitrogen.  The effect of atrazine on these and other organisms
            appears to be small.
      3.  Loss from photodecomposition and/or volatilization:  The
            significance of photodecomposition and/or volatilization of
            atrazine from soil is not fully understood.  Available data
            indicate that both occur to some extent if high temperatures and
            prolonged sunlight follow application before precipitation, but
            that these factors are of little significance in atrazine
            dissipation under most field conditions.  Atrazine is more subject
            to UV and volatility losses than simazine, but probably about
            equal or less subject to these losses compared to the commercial
            methylmercapto- or methoxytriazines.
      4.  Resultant average persistence at recommended rates:  The residual
            activity of atrazine in soil at selective rates for specific soil
            types is such that most rotational crops can be planted 1 year
            after applications, except under an arid or semiarid climate.
            Atrazine will persist longer under dry and cold conditions or
            conditions not conducive to maximum chemical or biological
            activity.  Broadcast rates needed in some of the finer and
            relatively higher organic matter soils of the north central states
            result in enough residue carryover, under some conditions, to
            injure small grains, alfalfa, and soybeans planted 12 months
            later.  Plant removal and chemical alteration are also factors in
            dissipation (58).
           Toxicological investigations conducted with bobwhite quail,
      mallard ducks, goldfish, rainbow trout, and bluegill sunfish have shown
      atrazine to have a very low toxicity to these species (58).
           Acute toxicity to fish and wildlife - AAtrex 80W
               Fish species                    96-hr LC50 (ppm)
               ____________                    ________________
               Rainbow trout                         4.5
               Bluegill sunfish                      >24
               Bird species                    8-day Dietary LC50 (ppm)
               ____________                    ________________________
               Bobwhite quail                           5,760
               Mallard duck                            19,650 (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:  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).
           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 mg/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 adn 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
           Nonflammable (58).
                                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:  Harmful if swallowed.  Avoid contact with eyes,
      prolonged contact with skin, inhalation of dust.  Use with adequate
      ventilation.  Do not contaminate food, feed, or water supplies (56).
      Very stable over several years of shelf life, with only slight
      sensitivity to natural light and extreme temperatures which would occur
      normally (58).
                       IX.  PROCEDURES FOR SPILLS AND LEAKS
                     IN CASE OF EMERGENCY, CALL, DAY OR NIGHT
                                  (800) 424-9300
                      PESTICIDE TEAM SAFETY NETWORK/CHEMTREC
                               X.  LITERATURE CITED
       8b. Thomson, W.T.  1981.  Agricultural chemicals - book 2:
               herbicides.  Revised ed.  Thomson Publications, Fresno, CA.
               274 pp.
      15c. American Conference of Governmental Industrial Hygienists.  1984.
               TLVs:  threshold limit values for chemical substances and
               physical agents in the work environment and biological exposure
               indices with intended changes for 1984-85.  Cincinnati, OH.
               116 pp.
      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.
      3/15/90