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    WORLD HEALTH ORGANIZATION             FOOD AND AGRICULTURE
                                          ORGANIZATION
    ORGANISATION MONDIALE DE LA SANTE     ORGANISATION POUR L'ALIMENTATION
                                          ET L'AGRICULTURE

                                                      VBC/DS/78.31

                                                      ORIGINAL: ENGLISH






    DATA SHEETS ON PESTICIDES No. 31

    PHOXIM






         It must be noted that the issue of a Data Sheet for a
    particular pesticide does not imply endorsement of the pesticide by
    WHO or FAO for any particular use, or exclude its use for other
    purposes not stated. While the information provided is believed to
    be accurate according to data available at the time when the sheet
    was compiled, neither WHO nor FAO are responsible for any errors or
    omissions, or any consequences therefrom.

    The issue of this document does    Ce document ne constitue pas une
    not constitute formal              publication. Il ne doit faire
    publication. It should not be      l'objet d'aucun compte rendu ou
    reviewed, abstracted or quoted     résumé ni d'aucune citation sans
    without the agreement of the       l'autorisation de l'Organisation
    Food  and Agriculture              des Nations Unies pour
    Organization of the United         l'Alimentation et l'Agriculture
    Nations or of the World Health     ou de l'Organisation Mondiale de
    Organization.                      la Santé.

                             CLASSIFICATION:

                             Primary Use: Insecticide

                             Chemical Group: Organophosphorus compound

                             Date Sheet No: 31

                             Date Issued:

    1.  GENERAL INFORMATION

    1.1  COMMON NAME:

    Phoxim

    1.1.1  Identity

    Alpha-[[(diethyoxyphosphinothioyl)-ox]-imino]benzeneacetonitrile

    CHEMICAL STRUCTURE

    1.1.2  Synonyms:

    SRA 7502
    Bayer 77488
    Baythion
    Volaton (formerly Valexon)
    OMS-1170

    Local synonyms:

    1.2  SYNOPSIS

    An organophosphorus insecticide of low acute oral and dermal
    toxicity to mammals but with a pronounced selectivity in toxicity to
    insects, particularly those in stored products and those affecting
    man.

    1.3  SELECTED PROPERTIES

    1.3.1.  Physical characteristics

    When pure, a yellow to yellow-brown liquid, melting point 5-6°C,
    boiling point 102°C at 0.01 mm Hg.  The technical material is a
    red-brown liquid. Density d 20 1.17 technical.
                                 4

    1.3.2  Solubility

    Water at 20°C, 7 ppm; readily soluble in alcohol, ketones,
    acetonitrile, hydrocarbons and to a lesser extent in vegetable and
    mineral oils.


    1.3.3  Stability

    Decomposes below boiling point at normal pressure. Badly stored
    formulations could develop a smell of cyanide. Stable in water and
    acids. Hydrolyses in alkaline solution.

    1.1.4  Vapour pressure (volatility)

    About 10-4 mm Hg for pure a.i. at 27°C.

    1.4  AGRICULTURE, HORTICULTURE AND FORESTRY

    1.4.1  Common formulations

    500 g/l emulsifiable concentrate, 40% wettable powder, 5% granules,
    10 granules and 800 g/l concentrate for ULV application.

    1.4.2  Pests mainly controlled

    Very effective against coleoptera and lepidoptera; and against
    wireworms, rootworms and dipterous larvae in soil.

    1.4.3  Use pattern

    Used for the control of insects liable to infest stored grain, peas,
    beans, rice, tobacco, dried fruit and skins. Application is as a
    spray up to 0.1% a.i. concentration, at up to 20 litres per 100 m2
    in empty stores, granaries and ships. May also be applied to empty
    jute sacks. Granular formulations are preferred for soil
    applications. It is of brief persistence and is non-systemic. It is
    very effective against locusts at 0.3-0.5 kg a.i./ha.

    1.4.4  Unintended effects

    Not intended for direct application to food or feeding stuffs. Toxic
    to fish and to some beneficial insects (see paragraphs 2.3.1 and
    2.3.3).

    1.5  PUBLIC HEALTH PROGRAMMES:

    A useful larvicide recommended for use in outdoor surface water.

    1.6  HOUSEHOLD USE:

    Not recommended for household use.

    2.  TOXICOLOGY AND RISKS

    2.1  TOXICOLOGY - MAMMALS

    2.1.1  Absorption route

    Absorbed from the gastrointestinal tract and more slowly through
    intact skin.

    2.1.2  Mode of action

    Cholinesterase inhibition after conversion to the oxygen analogue
    (P=O phoxim). This is rapidly hydrolysed in mammals to diethyl
    phosphoric acid. Variations in the rate of hydrolysis probably
    account for species variation.

    2.1.3  Excretion

    In mice 80% of an oral dose of 10.5 mg/kg is excreted in the urine
    in 80 hours. Excretion of higher doses is slower. Metabolites
    include phoxim carboxylic acid and 0,0 diethyl phosporothioc acid.

    2.1.4  Toxicity, single dose

    Oral:  LD50 rat (M) 2170 mg/kg
                    (F) 1976 mg/kg
              mouse (M) 1935 mg/kg
                    (F) 2340 mg/kg

    Dermal: LD50 rat (M) > 1000 mg/kg (maximum tested)

    Most susceptible species:  cat )
                               dog ) (F) Oral LD50 250-500 mg/kg
                               guinea-pig (F) oral LD50 600 mg/kg

    2.1.5  Toxicity, repeated doses

    Oral: Rats tolerated doses of 100 mg/kg daily for ten weeks
    without toxic symptoms, although there was moderate inhibition of
    cholinesterase.

    Inhalation: LD50 determined in a 4-hour test with statio
    treatments at 30 minute intervals was > 1.66 mg/m3 for rats and
    mice and between 1.16 and 1.66 mg/m3 for rabbits. The LC50 for
    rats exposed to a dynamic spray for four hours exceeded
    2500 mg/m3.

    Dermal: No information.

    Cumulation of compound: Phoxim is not cumulative.

    Cumulation of effect: Repeated high exposure may produce
    cumulative inhibitory effect on cholinesterase.

    2.1.6  Dietary studies

    Short-term: Rats of both sexes were given repeated oral doses of
    5, 15, 50, 150 and 500 mg/kg in the diet for three months. There
    were no deaths at any dose. Symptoms of cholinesterase depression
    were observed in the 500 mg/kg dose group. Food consumption and
    growth were not affected up to 150 mg/kg but the 500 mg/kg dose
    group had significantly lower body weights. The no-effect level was
    5 mg/kg. Rats were fed at 1, 2, 4, 6 and 10 mg/kg phoxim in the diet
    for up to five months. No adverse effects were noted. Calves were
    fed at dosage levels up to 2.6 mg/kg in diet for three months. The
    general state of animals remained normal but at the highest dose
    level, serum cholinesterase was inhibited after two months and
    erythrocyte cholinesterase reached a minimum after three months.

    Long-term: No information.

    2.1.7  Supplementary studies of toxicity

    Carcinogenicity: No information.

    Teratogenicity: No information.

    Neurotoxicity: Chickens were treated orally up to 50 mg/kg and
    intraperitoneally up to 37.5 mg/kg, no neurotoxic symptoms observed.

    2.1.8  Modification of toxicity

    No information.

    2.2  TOXICOLOGY - MAN

    2.2.1  Absorption

    Ingestion may be a significant route of absorption in man. However,
    dermal absorption from high concentration emulsifiable concentrates
    and particularly the 80% ULV concentrate could be important.

    2.2.2  Dangerous doses

    Single - Not known.

    Repeated - Not known.

    2.2.3  Observations on occupationally exposed workers

    A village-scale trial, wearing protective clothing, was carried out
    in Northern Nigeria in 1971. Workers handling the insecticide
    complained of weakness after work but no clinical symptoms were
    recorded. Two out of four spraymen complained of face pains lasting
    for one hour after work, but no other complaints or clinical effects
    were observed in spraymen or villagers exposed to phoxim. Very
    slight depression of whole-blood cholinesterase was dejected in some
    spraymen and some villagers.

    2.2.4  Observations on exposure of the general population

    No information.

    2.2.5  Observations of volunteers

    No information.

    2.2.6  Reported mishaps

    No information. Poisoning in humans by phoxim has not been reported.

    2.3  TOXICITY TO NON-MAMMALIAN SPECIES

    The entries in these sections are intended to draw attention to
    special risks and to give warnings of any need for special
    protection.

    2.3.1  Fish

    Toxic to fish. The LC50 (48-hour exposure) is: for rainbow trout
    < 1.0 mg/l, for goldfish 10-100 mg/l, for carp 1-10 mg/l and for
    mosquito fish LC100 5 mg/l.

    2.3.2  Birds

    Doves (Columbia livia) can tolerate at least 50 mg/kg. At
    100 mg/kg part of the dose was vomited. LD50 hens 37.5 mg/kg.

    2.3.3  Other species

    Toxic to bees by contact and vapour action. Contact LD50
    0.8 µg/insect.

    3.  FOR REGULATORY AUTHORITIES - RECOMMENDATIONS ON REGULATION OF
        COMPOUND

    3.1  RECOMMENDED RESTRICTIONS ON AVAILABILITY

    (For definition of categories, see introduction)

    80% concentrate for ULV application Category 3. Other liquid
    formulations over 25% and solid formulations over 40% Category 4. 
    All other formulations of lower concentration Category"

    3.2  TRANSPORTATION AND STORAGE

    All formulations - Should be transported or stored in clearly
    labelled leakproof containers out of reach of children, away from
    food or drink.

    3.3  HANDLING

    Formulations in Categories 3 and 4 - Adequate washing facilities
    should be provided at all times during handling and should be close
    to the site of the handling. Eating, drinking and smoking should be
    prohibited during handling and before washing after handling.

    Formulations in Category 5 - No facilities other than those needed
    for the handling of any other chemical may be required.

    3.4  DISPOSAL AND/OR DECONTAMINATION OF CONTAINER

    All formulations - Containers may be decontaminated (for method
    see paragraph 4.3 in Part 4). Decontaminated containers should not
    be used for food and drink. Containers that are not decontaminated
    should be burned or should be crushed and buried below topsoil. Care
    must be taken to avoid subsequent contamination of water sources.

    3.5  SELECTION, TRAINING AND MEDICAL SUPERVISION OF WORKERS

    Formulations in Categories 3 and 4 - Pre-employment medical
    examination and periodic cholinesterase test for workers desirable.
    Warning of workers to avoid contact essential.

    3.6  ADDITIONAL REGULATIONS RECOMMENDED IF DISTRIBUTED BY AIRCRAFT

    No special regulation recommended.

    3.7  LABELLING

    Formulations in Categories 3 and 4 - Minimum cautionary statement:
    "Phoxim is an organophosphorus compound which inhibits
    cholinesterase. It is of moderate toxicity bat may be poisonous if
    swallowed. Keep the material out of reach of children and well away
    from foodstuffs, animal feed and their containers. If poisoning
    occurs call a physician. Atropine and pralidoxime are specific
    antidotes and artificial respiration may be needed".

    Formulations in Category 5 - Minimum cautionary statement

    This formulation contains phoxim. Keep the material out of reach of
    children and well away from foodstuffs, animal feed and their
    containers.

    3.8  RESIDUES IN FOOD

    Maximum residue levels have not yet been recommended by the FAO/WHO
    Meeting on Pesticide Residues.

    4.  PREVENTION OF POISONING IN MAN AND EMERGENCY AID

    4.1  PRECAUTIONS IN USE

    4.1.1  General

    Phoxim is an organophosphorus insecticide of moderate to low
    mammalian toxicity. It can be absorbed by ingestion, by inhalation
    of dust and to some extent through intact skin. Although dermal
    absorption from diluted spray is of little significance, absorption
    from high concentration liquid formulations (especially the 80% ULV
    concentrate) may be important. In dilute liquid formulations the
    vehicle (solvent) may be more toxic than the insecticide.

    4.1.2  Manufacture and formulations

    Although volatility is low, vapour and dust should be controlled.
    Protective equipment for skin and respiratory protection is
    desirable.

    4.1.3  Mixers and applicators

    When opening the container and when mixing, care should be taken to
    avoid contact with the mouth and eyes. If necessary a facial visor
    and gloves should be worn. Mixing, if not mechanical, should always
    be carried out with a paddle of appropriate length, Splashes should
    be washed immediately from the skin or eyes with large quantities of
    water. Before eating, drinking or smoking, hands and other exposed
    skin should be washed.

    4.1.4  Other associated workers (including flagmen in aerial
           operations)

    Persons exposed to phoxim and associated with its application should
    observe the precautions described above in 4.1.3 under "Mixers and
    applicators".

    4.1.5  Other populations likely to be affected

    Populations will not be exposed to hazardous amounts of phoxim
    during good agricultural practice.

    4.2  ENTRY OF PERSONS INTO TREATED AREAS

    Phoxim degrades rapidly under field conditions and persons may enter
    treated areas as soon as the spray has dried without being exposed
    to hazardous amounts of phoxim.

    4.3  DECONTAMINATION OF SPILLAGE AND CONTAINERS

    Residues in containers should be emptied in a diluted form into a
    deep pit taking care to avoid ground waters. The empty container may
    be decontaminated by rinsing two or three times with water and
    scrubbing the sides. An additional rinse should be carried out with
    5% sodium hydroxide solution which should remain in the container
    overnight. Impermeable gauntlets should be worn during this work and
    a soakage pit should be provided for the rinsings. Decontaminated
    containers should not be used for food and drink. Spillage of phoxim
    and its formulations should be removed by washing with 5% sodium
    hydroxide solution and then rinsing with large quantities of water.

    4.4  EMERGENCY AID

    4.4.1  Early symptoms of poisoning

    Early symptoms of poisoning following the ingestion of phoxim may
    include excessive sweating, headache, weakness, giddiness, nausea,
    vomiting, stomach pains, blurred vision, slurred speech, and muscle
    twitching. If a massive dose has been swallowed there may be
    convulsion, coma, loss of reflexes and loss of sphincter control.
    Symptoms of poisoning are very unlikely to occur following dermal
    contact.

    4.4.2  Treatment before person is seen by a physician, if these
           symptoms appear exposure

    If swallowed, vomiting should be induced if the person is conscious.
    the event of collapse, artificial respiration should be given.

    5.  FOR MEDICAL AND LABORATORY PERSONNEL

    5.1  MEDICAL DIAGNOSIS AND TREATMENT IN CASES OF POISONING

    5.1.1  General information

    An organophosphorus insecticide of moderate to low mammalian
    toxicity which can be absorbed by ingestion, by inhalation and to
    some extent through intact skin. Although dermal absorption from
    diluted spray may not be significant absorption from high
    concentration liquid formulations may be important. In dilute
    formulations the vehicle (solvent) may be more toxic than the
    insecticide. Phoxim itself is a weak inhibitor of acetyl
    cholinesterase but is metabolized to a more active inhibitor which
    is then quickly inactivated; the metabolites are excreted in the
    urine. Poisoning in man has not yet been reported.

    5.1.2  Symptoms and signs

    Based upon studies and upon symptoms of poisoning from other
    organophosphorus pesticides, initial symptoms of poisoning may
    include excessive sweating, headache, weakness, giddiness, nausea,
    vomiting, stomach pains, blurred vision, slurred speech and muscle
    twitching. In the event of ingestion of an excessive dose more
    advanced symptoms of poisoning may be convulsions, coma, loss of
    reflexes and loss of sphincter control.

    5.1.3  Laboratory

    The most important finding is reduction in activity of blood
    cholinesterases.

    5.1.4  Treatment

    If pesticide has been ingested, unless the patient is vomiting,
    rapid gastric lavage should be performed using 5% sodium
    bicarbonate, if available. In spite of the low dermal toxicity after
    skin contact, it is advisable to wash the skin with soap and water.
    If the compound has entered the eyes, they should be washed with a
    lot of water. Persons without signs of respiratory inefficiency out
    with manifest peripheral symptoms should be treated with 2-4 mg of
    atropine sulfate and 1000-2000 mg of pralidoxime chloride or 250 mg
    of zoxogonin (adult dose) by slow intravenous injection. More
    atropine may be given as needed. Persons with severe intoxication
    with respiratory, difficulties, convulsions and unconsciousness
    should immediately be given atropine and a reactivator. In such
    severe cases 4-6 mg of atropine sulfate should be given initially
    followed by repeated doses of 2 mg at 5-10 minute intervals. The
    patient's condition including respiration, blood pressure, pulse

    frequency, salivation and convulsions should be carefully observed
    as a guide to further administration of atropine. If the patient is
    cyanotic, artificial respiration should be given at the same time as
    atropine sulfate. The airways should be kept free and artificial
    respiration if required, should be preferably by mechanical means.
    If necessary intubation should be performed.

    Contraindicated are morphine, barbiturates, phenothiazine
    tranquillizers and central stimulants of all kinds.

    5.1.5  Prognosis

    As there have been no reports of poisoning of man with phoxim the
    prognosis is not known. By analogy with other moderately toxic
    organophosphorus compounds it may be assumed that if the acute toxic
    effect is survived the chances of complete recovery are good. In
    very severe cases following the ingestion of a massive dose of
    phoxim it is possible that without adequate artificial respiration
    prolonged hypoxia could give rise to permanent brain damage.

    5.1.6  References of previously reported cases

    None.

    5.2  SURVEILLANCE TESTS

                                     Normal  Action   Symptomatic
    Test                             level    level    level

    Plasma cholinesterase            100%1     50%      variable
    Erythrocyte cholinesterase       100%      70%      usually < 40%

    5.3  LABORATORY METHODS

    References are given only.

    5.3.1  Detection and assay of compound

    Particulars of a GLC method for analysis of residues in plants using
    a thermionic phosphorus detector are available from Bayer,
    Leverkusen. [Drager, G. (1969) Pflantzenschutz Nachrichten 22,
    No. 3, 301]

               
    1Percentage of pre-exposure activity by any test.

    5.3.2  Other tests in cases of poisoning

    Levels of cholinesterase in blood provide the most useful diagnosis
    of poisoning. See: Michel, N. O. (1949) J. Lab. Clin. Med., 34,
    1564-1568: Ellman, G. L., Courtney, K. D., Andreas, V. Jr. &
    Featherstone, R. M. (1961) Biochem., Pharmacol., 7, 88-95.


                                    * * *

See Also:
        Phoxim (PIM 452)