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Dichlorvos (DDVP, Vapona) - Chemical Profile 3/88


      CHEMICAL name:      2,2-Dichlorovinyl dimethyl phosphate (56)


      TRADE name(S):      Vapona, Vaponite (56)

      FORMULATION(S):  Emulsifiable concentrates, soluble concentrate,
      wettable powder, ready-to-use sprays, aerosols, space sprays, resin
      strips (Mafu Strip, No-Pest Strip Insecticide), flea collars, baits.
      Concentrates sold under the name of Vaponite are for professional pest
      control use only.  Formulated as an antihelmintic for swine (Atgard),
      horses (Equigard), and dogs (Task, Canogard) (56).

      TYPE:               Organophosphate insecticide

      BASIC PRODUCER(S):  Shell Chemical Company (now owned by Dupont)
                          A Division of Shell Oil
                          P. O. Box 3871
                          Houston, TX 77001

      STATUS:             Restricted use.
                          A Special Review for dichlorvos was issued during
                          the week of February 24, 1988 by EPA.  The Special
                          Review is based on risks of cancer and adverse liver
                          effects, and cholinesterase inhibition. The agency
                          also noted restrictions on use imposed by the
                          registration standard.

      PRINCIPAL USES:  A contact and stomach poison, it also acts as a
      fumigant.  Controls household and public health pests, stored product
      insects, horn flies, house flies, face flies, stable flies, gnats,
      and mosquitoes on lactating dairy animals and beef cattle.  Control of
      mushroom flies; also aphids, spider mites, caterpillars, thrips, white
      flies in glasshouse crops, and outdoor fruit and vegetables (56).

                                I.  EFFICACY

      Important Pests Controlled:  Ants, aphids, mites, mealybugs, ticks,
      Drosophila, centipedes, moths, cockroaches, crickets, fleas, flies,
      gnats, mosquitoes, sowbugs, spiders, wasps and many others (8a).
           Extremely fast knock-down effects.  Residual control of 2-3 weeks
      may be obtained (8a).

                           II.  PHYSICAL PROPERTIES

      MOLECULAR FORMULA:   C4 H7 Cl2 O4 P (62)

      MOLECULAR WEIGHT:    221.0 (62)

      PHYSICAL STATE:      Colorless to amber liquid (pure compound) (62)

      ODOR:                Aromatic odor (pure compound) (62)

      BOILING POINT:       35 C/0.05 mmHg (pure compound) (62)

      VAPOR PRESSURE:      1.6 Pa at 20 C (pure compound) (62)

      SOLUBILITY:          c.10 g/l water at 20 C (pure compound) (62)

                         III.  HEALTH HAZARD INFORMATION

      OSHA STANDARD:  1 mg/m3 averaged over an 8-hr work shift (14)

      NIOSH RECOMMENDED LIMIT:  None established

      ACGIH RECOMMENDED LIMIT:  TWA (Time Weighted Average) = 0.1 ppm, 1
                                mg/m3; STEL (Short Term Exposure Limit) = 0.3
                                ppm (deleted), 3 mg/m3 (deleted); skin notation

           A.  ACUTE TOXICITY

               DERMAL:  LD50 = 75 mg/kg (rat); 107 mg/kg (rabbit) (56).
                        LD50 = 75-210 mg/kg (rat) (62)

               ORAL:    LD50 = 56-108 mg/kg (rat) (62)
                        LD50 = 56-80 mg/kg (rat) (56)

               INHALATION:  LC50 (4-hr): 13.2 mg/m3 (mouse); 14.8 mg/m3 (rat)

               EYES:    Not known to be an eye irritant (14)


           Daily exposure to concentrations which are insufficient to produce
      symptoms following a single exposure may result in the onset of
      symptoms.  Continued daily exposure may be followed by increasingly
      severe effects.
           In a study of 13 workers exposed for 12 months to an average
      concentration of 0.7 mg/m3, the erythrocyte cholinesterase activity
      was reduced by approximately 35%, and the serum cholinesterase activity
      was reduced by 60%; the results of other tests and of thorough
      medical examinations conducted at regular intervals were entirely
      normal (14).
           In 90-day feeding trials rats receiving 1000 mg/kg diet showed no
      intoxication (62).


           Little or no hazard to birds, fish, and beneficial insects.
      Hazardous to honey bees.  Biological magnification unknown. Nonphytotoxic

      when used as directed (1).
           LC50 (24-hr) for bluegill is 1 mg/l.  It is highly toxic to
      honeybees and toxic to birds (62).

      Approximate Residual Period:  Only 1-2 days on plant surfaces; much
      longer life when impregnated into resin strips or similar carriers (1).


           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.


           Symptoms of acute poisoning develop during exposure or within 12
      hours (usually within four hours) of contact.  headACHE, DIZZINESS,
      CRAMPS, DIARRHEA, and SWEATING are common early symptoms.  Blurred or
      dark vision, confusion, tightness in the chest, wheezing, productive
      cough, and PULMONARY EDEMA may occur.  Incontinence, unconsciousness
      and convulsions indicate very severe poisoning.  SLOW HEARTBEAT,
      salivation, and tearing are common.  TOXIC PSYCHOSIS, with manic or
      bizarre behavior, has led to misdiagnosis of acute alcoholism.  Slowing
      of the heartbeat may rarely progress to complete sinus arrest.
      RESPIRATORY DEPRESSION may be fatal.  Continuing daily absorption of
      organophosphate at intermediate dosage may cause an INFLUENZA-LIKE
      ILLNESS characterized by weakness, anorexia, and malaise (25).

           SKIN CONTACT:  Immediately wash the contaminated skin using soap or
      mild detergent and water.  Get medical attention immediately (14).

           INGESTION:  If the person is conscious, give large quantities of
      water immediately.  Try to get the person to vomit by having him touch
      the back of his throat with his finger.  Do not make an unconscious
      person vomit.  Get medical attention immediately (14).

           INHALATION:  Move the exposed person to fresh air at once.  If
      breathing has stopped, perform artificial respiration.  Keep the affected
      person warm and at rest.  Get medical attention as soon as possible (14).

           EYE CONTACT:  Wash eyes immediately with large amounts of water,
      lifting the lower and upper lids occasionally.  Get medical attention
      immediately.  Contact lenses should not be worn when working with this
      chemical (14).


      Administer ATROPINE SULFATE intravenously, or intramuscularly, if IV
      injection is not possible.
      In MODERATELY SEVERE poisoning:  Adult dosage:  0.4-2.0 mg repeated
      every 15 minutes until atropinization is achieved:  tachycardia (pulse
      of 140 per minute), flushing, dry mouth, dilated pupils.  Maintain
      atropinization by repeated doses for 2-12 hours or longer depending on
      severity of poisoning.
      Dosage for children under 12 years:  0.05 mg/kg body weight, repeated
      every 15 minutes until atropinization is achieved.  Maintain
      atropinization with repeated dosage of 0.02-0.05 mg/kg.
      SEVERELY POISONED individual may exhibit remarkable tolerance to
      atropine; two or more times the dosages suggested above may be needed.
      Administer PRALIDOXIME (Protopam (TM)-Ayerst, 2-PAM) in cases of severe
      poisoning in which respiratory depression, muscle weakness and
      twitchings are severe.
      Adult dosage:  1.0 gm intravenously at no more than 0.5 gm per minute.
      Child's dose (under 12 years):  20-50 mg/kg (depending on severity of
      poisoning) intravenously, injecting no more than half the total dose
      per minute.
      Dosage of pralidoxime may be repeated in 1-2 hours, then at 10-12 hour
      intervals if needed.  In very severe poisonings, dosage rates may be
      doubled (25).


           Toxic gases and vapors (such as hydrogen chloride gas, phosphoric
      acid mist, and carbon monoxide) may be released in a fire involving
      dichlorvos (14).

                              VII.  COMPATIBILITY

           Breaks down in water dilutions.  Check label for compatibility of
      given formulation (1).  Do not combine with alkaline compounds or with
      Morestan or Euparen.  Compatible with other compounds (8a).

                           VIII.  PROTECTIVE MEASURES

      STORAGE AND HANDLING:  Poisonous if swallowed, inhaled, or absorbed
      through skin.  Do not contaminate feed or foodstuffs.  Do not drink
      any alcoholic beverages before or during spraying since alcohol promotes
      absorption of organic phosphates. No shelf-life problems with unopened
      package (No-Pest Strip Insecticide) (56).

      PROTECTIVE CLOTHING:  To prevent repeated or prolonged skin contact
      with dichlorvos:  use impervious clothing, gloves, face shields (eight-
      inch minimum), and other appropriate protective clothing (14).

      PROTECTIVE EQUIPMENT:  When engineering controls are inadequate, or not
      technically feasible, respirators may be used to control exposure.
      The only ones permitted are those that have been approved by the Mine
      Safety and Health Administration or by the National Institute for
      Occupational Safety and Health (14).



                                 (800) 424-9300

           Persons not wearing protective equipment and clothing should be
      restricted from areas of spills or leaks until cleanup has been

           If dichlorvos is spilled or leaked, the following steps should be

           1.  Ventilate area of spill or leak.
           2.  Collect for reclamation or absorb in vermiculite, dry sand,
               earth, or a similar material.

           Waste disposal method:

           Dichlorvos may be disposed of by absorbing it in vermiculite, dry
      sand, earth or a similar material and disposing in a secured sanitary
      landfill (14).

                               X.  LITERATURE CITED

       1.  Harding, W.C.  1979.  Pesticide profiles, part one: insecticides

               and miticides.  Univ. Maryland, Coop. Ext. Serv. Bull. 267.
               30 pp.

       8a. Thomson, W. T.  1976.  Agricultural chemicals - book 1:
               insecticides, acaricides, and ovicides.  Revised ed.  Thomson
               Publ., Indianapolis, IN.  232 pp.

      14.  U. S. Department of Health and Human Services, National Institute
               for Occuptational Safety and Health.  1981.  Occupational
               health guidelines for chemical hazards.  F. W. Mackinson, R.
               S. Stricoff, L. J. Partridge, Jr., and A. D. Little, Inc.,
               eds.  DHHS (NIOSH) Publ. No. 81-123.  Washington, DC.

      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.

      62.  The Pesticide Manual:  A World Compendium, 7th ed.  1983.  C.R.
               Worthing, ed.  The British Crop Protection Council, Croydon,
               England.  695 pp.