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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/80.43

                                                      ORIGINAL: ENGLISH






    DATA SHEETS ON PESTICIDES No. 43

    March 1980

    JODFENPHOS






         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

                             Secondary use: Acaricide

                             Chemical group: Organophosphorus compound.

                             Date issued: March 1980

    1.  GENERAL INFORMATION

    1.1  COMMON NAME:

    Jodfenphos (ISO), iodofenphos in French

    1.1.1  Identity:

    O-(2,5-dichloro-4-iodophenyl) O,O-dimethyl phosphorothioate

    CHEMICAL STRUCTURE

    1.1.2  Synonyms:

    Iodofenphos    Alfacron(R)
    Nuvanol(R)     C 9491
    OMS-1211       ENT 27408

    Local synonyms:

    1.2  SYNOPSIS:

    An organophosphorus insecticide and acaricide of low mammalian
    toxicity, used for the protection of stored products and in public
    health. It is active after metabolism.

    1.3  SELECTED PROPERTIES

    1.3.1  Physical characteristics

    Colourless crystals with a mild odour, m.p. 76°C.

    1.3.2  Solubility

    At 20°C, practically insoluble in water (2 mg/l): soluble in
    ketones, aromatic hydrocarbons and aliphatic chlorinated
    hydrocarbons: slightly soluble in alcohols and aliphatic
    hydrocarbons.

    1.3.3  Stability

    Relatively stable in weakly acid, neutral and weakly alkaline media,
    unstable in strongly acid and alkaline media.

    1.3.4  Vapour pressure

    8 x 10-7 mmHg at 20°C.

    1.4  AGRICULTURE, HORTICULTURE AND FORESTRY

    No recommended use.

    1.5  PUBLIC HEALTH PROGRAMME

    1.5.1  Common formulations

    50 g/kg dust, 200 ml/l emulsifiable concentrate (EC), 500 g/kg
    wettable power (WP), 500 ml/l liquid suspension = flowable (FW).

    1.5.2  Susceptible pests

    Effective against a wide range of insect pests in public hygiene
    including cockroaches, sucking lice, bugs, flies and mosquitos,
    fleas, and mites and ticks.

    1.5.3  Use pattern

    Mainly used against livestock pests and vectors, applied as dust for
    the control of ectoparasites, as emulsion against mosquito larvae
    and mites, as residual sprays against flies and mosquitos, and as
    ULV spray against flies and mosquitos (larvae and adults).

    1.5.4  Unintended effects

    No information.

    1.6  HOUSEHOLD USE

    1.6.1  Common formulations

    See 1.5.1.

    1.6.2  Susceptible pests

    Jodfenphos is effective against a wide range of insect pests in the
    household, such as silverfish, earwigs, cockroaches, psocids, ants,
    wasps, beetles, moths, flies, mosquitos, fleas, mites and spiders.

    1.6.3  Use pattern

    Aerosols and emulsions are suitable for the control of crawling
    household pests as well as for long-lasting protection, e.g. against
    silverfish, carpet beetles and coddling moth. Dust is applied
    against ants, cockroaches and silverfish.

    1.6.4  Unintended effects

    No information.


    1.7  PROTECTION OF STORED PRODUCTS

    1.7.1  Common formulations

    See 1.5.1.

    1.7.2  Susceptible pests

    Jodfenphos is effective against various insect pests in stored
    products such as psocids, beetles, weevils, moths and mites.

    1.7.3  Use pattern

    Emulsions are used in surface clean-out sprays. Wettable powders and
    flowable formulations are used as residual surface sprays against
    various pests, such as moths, beetles, weevils and mites.

    1.7.4  Unintended effects

    No information.

    2.  TOXICOLOGY AND RISKS

    2.1  TOXICOLOGY - MAMMALS

    2.1.1  Absorption route

    May be absorbed from the gastrointestinal tract, by the intact skin
    and by inhalation.

    2.1.2  Mode of action

    An organophosphorus cholinesterase inhibitor.

    2.1.3  Excretion products

    In mammals, jodfenphos is rapidly eliminated, mainly in the urine
    (82% of the administered dose after 24 hours). The main excretion
    products are acid metabolites: phosphorus acid, dimethyl phosphoric
    acid, monomethyl phosphoric acid, dimethyl phosphorothioic acid and
    desmethyl - jodfenoxon.

    2.1.4  Toxicity, single dose

    Oral: LD50 rat (M & F): 2100-3000 mg/kg
          LD50 dog (M & F): 3000 mg/kg

    Dermal: LD50 rat (M & F): 2150 mg/kg

    2.1.5  Toxicity, repeated doses

    Oral: Female rats fed 4.5 mg technical grade jodfenphos daily for
    90 days showed no effect or clinical symptoms. See also 2.1.6
    Dietary studies, short-term.

    Dermal: Male and female rabbits exposed to 300 mg technical
    jodfenphos (micronized) daily for 21 days showed no effect or
    clinical symptoms.

    Inhalation: LC50 (rats) 246 mg/m3. Male and female rats were
    exposed to technical grade jodfenphos 6 hours daily for 19 days. The
    animals showed mild clinical symptoms typical of organophosphorus
    poisoning and slightly reduced cholinesterase activity.

    Cumulation of compound: Does not accumulate in body tissues to any
    significant extent.

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

    2.1.6  Dietary studies

    Short-term: In a 91-day study, body weights of male rats fed
    500 mg jodfenphos/kg diet were consistently lower than female
    controls and rats of both sexes. Haematological parameters were
    within normal range. Marginal inhibition of erythrocyte
    cholinersterases was observed at 50 mg/kg and marked inhibition at
    500 mg/kg. Plasma cholinesterase was significantly inhibited at both
    intake levels. Erythrocyte and plasma cholinesterases returned to
    normal or near normal activity during the 4-week recovery period. At
    autopsy, there were no gross pathological changes that could be
    attributed to ingestion of the chemical. The no-effect level was
    5 (mg/kg)/day. In another 91-day study with dogs fed 15, 150 and
    1500 mg/kg diet, all test generally lost weight. Food consumption
    was reduced in the 1500 mg/kg group. Plasma cholinesterase was not
    affected at 15 mg/kg but was inhibited significantly at 150 mg/kg.
    There was no effect on erythrocyte cholinesterase at 15 mg/kg,
    marginal inhibition at 150 mg/kg and significant inhibition at
    1500 mg/kg. Brain cholinesterase was significantly inhibited at
    150 mg/kg and 1500 mg/kg. Inhibited erythrocyte and plasma enzyme
    returned to normal during the 4-week recovery period. At autopsy, no
    organs showed any change attributable to jodfenphos. The no-effect
    level was 15 (mg/kg)/day.

    Long-term: No information.

    2.1.7  Supplementary studies of toxicity

    Carcinogenicity: No information.

    Teratogenicity: Pregnant female rats were treated from day 6
    through 15 of pregnancy with 0.0, 6.5, 20, 65 and 200 (mg/kg)/day
    jodfenphos. No gross malformations nor any increased incidence of
    abnormalities were observed in the offspring and their weight at
    term was normal despite the distinct toxic effects in a number of
    treated mothers at high doses.

    Mutagenicity: Jodfenphos showed no mutagenic effect on
    streptomycin-dependent

    Escherichia coli SD4 strain by the paper disc method.

    Delayed neurotoxicity: Hens received 2000 mg/kg technical grade
    jodfenphos orally, twice at an interval of 3 weeks (LD50);
    histopathological examinations showed no neurotoxic effects.

    2.1.8  Modification of toxicity

    No information.

    2.2  TOXICOLOGY - MAN

    2.2.1  Absorption

    May be absorbed from the gastrointestinal tract, by inhalation or by
    the intact skin.

    2.2.2  Dangerous doses

    Single: Not known.

    Repeated: Not known.

    2.2.3  Observations of occupationally exposed workers

    Jodfenphos has been applied as a residual indoor spray for adult
    mosquito control. There have been no complaints attributable to
    exposure to the pesticide recorded among the baggers and operators
    who sprayed jodfenphos for 8 days.

    2.2.4  Observations on exposure of the general population

    In a malaria control trial in a village of 1819 inhabitants in
    Nigeria, whole blood cholinesterase levels were unaffected among
    exposed villagers and no complaints were received.

    2.2.5  Observations of volunteers

    No information.

    2.2.6  Reported mishaps

    None.

    2.3   TOXICITY TO NON-MAMMALIAN SPECIES

    2.3.1  Fish

    Jodfenphos has a medium to high toxicity to fish and water fleas
    (Daphnia spp.). Those fish living in potential mosquito breeding
    places can normally tolerate the recommended dosage for control of
    mosquito larvae of 0.1 mg a.i./l, but this rate should not be
    exceeded. On other water organisms such as algae, saltwater
    crustaceans and snails there was no effect at a concentration of
    0.1 mg/l.

    2.3.2  Birds

    Slightly toxic to birds.

    2.3.3  Other species

    Toxic to bees.

    3.  FOR REGULATORY AUTHORITIES - RECOMMENDATIONS ON REGULATION OF
        COMPOUND

    3.1  RECOMMENDED RESTRICTIONS ON AVAILABILITY

    (For definitions of categories, see introduction).

    Liquid and solid formulations above 10%: category), 4

    Other formulations: category 5

    3.2  TRANSPORTATION AND STORAGE (UN classification 6.1)

    Formulations in category 4 - Should be transported or stored in
    clearly labelled, rigid and leakproof containers, under lock and
    key, secure from access by unauthorized persons and children. No
    food or drink should be transported or stored in the same
    compartment.

    Formulations in category 5 - Should be transported or stored in
    clearly labelled, leakproof containers out of reach of children,
    away from food and drink.

    3.3  HANDLING

    Formulations in category 4 - Protective clothing should be used
    for those handling the compound. Adequate facilities should be
    available at all times during handling and should be close to the
    site of 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 handling of any chemical may be required.

    3.4  DISPOSAL AND/OR DECONTAMINATION OF CONTAINER:

    Containers may be decontaminated. Decontaminated containers should
    not be used for food and drink. If not decontaminated, emptied
    containers should be burned or 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 category 4 - Pre-employment medical examination of
    workers desirable. Workers suffering from active hepatic or renal
    disease should be excluded from contact. Pre-employment and periodic
    cholinesterase tests for workers desirable. Special account should
    be taken of the workers' mental ability to comprehend and follow
    instructions. Training of workers in techniques to avoid contact
    essential.

    Formulations in category 5 - No special cholinesterase test for
    workers necessary. Warning of workers to minimize contact essential.

    3.6  ADDITIONAL REGULATIONS RECOMMENDED IF DISTRIBUTED BY AIRCRAFT

    All formulations - Pilots and loaders should have special training
    in application methods and recognition of early symptoms of
    poisoning and must wear a suitable respirator. Flagmen, if used,
    should wear overalls and be located well away from the dropping
    zone.

    3.7  LABELLING

    Formulations in category 4 - Minimum cautionary statement:
    Jodfenphos is an organophosphorus compound which inhibits
    cholinesterase. It is poisonous if swallowed. It may be absorbed
    through the skin or inhaled as a dust or mist. Avoid skin contact;
    wear protective gloves, and clean protective clothing when handling
    the material. Wash thoroughly with soap and water after using. 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 the specific
    antidotes and artificial respiration may be needed.

    Formulations in category 5 - Minimum cautionary statement: This
    formulation contains jodfenphos, a toxic substance which is
    poisonous if swallowed. 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 limits for jodfenphos have not yet been considered
    by the WHO/FAO Meeting on Pesticide Residues.

    4.  PREVENTION OF POISONING IN MAN AND EMERGENCY AID

    4.1 PRECAUTIONS IN USE

    4.1.1  General

    Jodfenphos is an organophosphorus pesticide of low mammalian
    toxicity. It penetrates the intact skin and is also absorbed by
    inhalation of dust and spray mist, and from the gastrointestinal
    tract. Highly concentrated formulations should be handled by trained
    personnel wearing protective clothing.

    4.1.2  Manufacture and formulation

    No TLV values have been recommended. Closed systems and forced
    ventilation may be required to reduce as much as possible the
    exposure of workers to the chemical.

    4.1.3  Mixers and applicators

    When opening the container and when mixing, protective impermeable
    boots, clean overalls, gloves and respirator should be worn. Mixing,
    if not mechanical should always be carried out with a paddle of
    appropriate length. When spraying indoors, a face mask should be
    worn, as well as an impermeable hood, clothing, boots and gloves.
    The applicator should avoid working in spray mist and avoid contact
    with the mouth. Particular care is needed when equipment is washed
    after every use, including the insides of gloves and boots. Splashes
    must 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 jodfenphos and associated with its application
    should wear clean overalls and observe the precautions described
    above in 4.1.3 under "Mixers and applicators".

    4.1.5  Other populations likely to be affected

    With correct use in agriculture and public health, the general
    population should not be exposed to hazardous amounts of jodfenphos.

    4.2  ENTRY OF PERSONS INTO TREATED AREAS:

    The general population should be kept out of treated areas for at
    least one day.

    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 contamination of groundwaters. The
    empty containers 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
    the work and a soakage pit should be provided for the rinsings.
    Decontaminated containers should not be used for food and drink.
    Spillage of jodfenphos 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

    These may include excessive sweating, headache, weakness, giddiness,
    nausea, vomiting, stomach pains, blurred vision, slurred speech and
    muscle twitching. Later there may be convulsions, coma, loss of
    reflexes and loss of sphincter control.

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

    The person should stop work immediately, remove contaminated
    clothing and wash the affected skin with soap and water, if
    available, and flush with large quantities of water. If swallowed,
    vomiting should be induced, if the person is conscious. In the event
    of collapse, artificial respiration should be given, bearing in mind
    that if mouth-to-mouth respiration is used, vomit may contain toxic
    amounts of jodfenphos.

    5.  FOR MEDICAL AND LABORATORY PERSONNEL

    5.1  MEDICAL DIAGNOSIS AND TREATMENT IN CASES OF POISONING

    5.1.1  General information

    Jodfenphos is an organophosphorus pesticide of low toxicity which
    may be absorbed from the gastrointestinal tract as well as by
    inhalation and through the intact skin. It acts by inhibiting
    acetylcholinesterase. Continuous exposure to low amounts may inhibit
    blood cholinesterase to hazard levels.

    5.1.2  Symptoms and signs

    Initial symptoms o£ poisoning may include excessive sweating,
    headache, weakness, giddiness, nausea, vomiting, stomach pains,
    blurred vision, slurred speech and muscle twitching. More advanced
    symptoms of poisoning may be convulsions, coma, loss of reflexes and
    loss of sphincter control.

    5.1.3  Laboratory

    The most important laboratory finding is reduction in activity of
    blood cholinesterases. Urinary levels of organic phosphorus
    containing metabolites could also be used as a measure of exposure.
    Neither method is specific for jodfenphos.

    5.1.4  Treatment

    If the pesticide has been ingested, unless the patient is vomiting,
    rapid gastric lavage should be performed using 5% sodium bicarbonate
    if available. For skin contact, the skin should be washed with soap
    and water. If the compound has entered the eyes, they should be
    washed with isotonic saline. Persons without signs of respiratory
    inefficiency 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 toxogonin (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 should be applied, if required,
    preferably by mechanical means. If necessary, intubation should be
    performed. Contraindications are morphine, barbiturates,
    phenothiazine, tranquillizers and central stimulants of all kinds.

    5.1.5  Prognosis

    If the acute toxic effect is survived and adequate artificial
    respiration has been given, if needed, the chances of recovery are
    good. However, in very severe cases, particularly if artificial
    respiration has been inadequate prolonged anoxia may give rise to
    permanent brain damage.

    5.1.6  References of previously reported cases

    None.

    5.2  SURVEILLANCE TESTS

    
    Test                           Normal level*       Action level*      Symptomatic level*

    Plasma cholinesterase              100%                50%                  Variable

    Erythroctye cholinesterase         100%                70%               Usually < 40%

    
    Urinary levels of ether extractable organic phosphorus may also be
    used to determine the degree of exposure.

    5.3  LABORATORY METHODS

    References only are given.

    5.3.1  Detection and assay of compound

    Residues of jodfenphos are determined by GLC using electron-capture
    of a phosphorus specific flame photometric detector. Particulars of
    the methods can be obtained from Ciba-Geigy Ag, Basle, Switzerland.

    5.3.2  Other tests in cases of poisoning

    Levels of cholinesterase in the blood, particularly plasma, provide
    the most useful diagnosis of poisoning:

                   
    *Expressed as percentage of pre-exposure activity.

    Michel, N. O. (1949) J. Lab. Clin. Med., 34, 1564

    Ellman, G. L. et al. (1961) Biochem. Pharmacol., 7, 88

    Urinary levels of ether extractable organic phosphorus (Mattson &
    Sledak, 1960) or dimethyl phosphate (Shafik & Enos, 1969) can also
    be used to determine exposure.



                                    = = =
See Also:
        Jodfenphos (PIM 873)