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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/77.25

                                                      ORIGINAL: ENGLISH






    DATA SHEETS ON PESTICIDES No. 25

    DECEMBER 1976

    PROPOXUR






         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.

    Part 1 - General information

                                  CLASSIFICATION:

                                  Primary use:     Insecticide

                                  Secondary uses:  acaricide

                                  Chemical group:  carbamate

                                  Data sheet No.   25

                                  Date issued:     December 1976

    1.1  COMMON NAME - PROPOXUR

    Identity: 2-isopropoxyphenyl N-methylcarbamate

    CHEMICAL STRUCTURE

    Synonyms:                   Local synonyms:
    BAYGON
    BAY 9010 Baygon
    BAY 39007
    UNDEN
    OMS 33

    ARPROCARB

    1.2  SYNOPSIS

    A carbamate insecticide of moderate mammalian toxicity which is
    rapidly metabolized and does not accumulate in tissues.

    1.3  SELECTED PROPERTIES

    1.3.1  Physical characteristics

    A white crystalline powder with a faint characteristic odour and a
    melting point of 86-91.5°C (technical a.i.).

    1.3.2  Solubility:

    Its solubility in water is 0.2% at 20°C; it is soluble in polar
    organic solvents, but only slightly soluble in non-polar organic
    solvents.

    1.3.3  Stability:

    It is unstable in highly alkaline media with a half-life at pH 10 at
    20°C of 40 minutes.

    1.3.4  Vapour pressure (Volatility):

    (Volatility) 10-2 mm Hg at 120°C.

    1.4  AGRICULTURE, HORTICULTURE AND FORESTRY

    1.4.1  Common formulations

    Wettable powders 50%; dusts 2%, granules, oils, emulsifiable
    concentrates 200 g/litre, pressurized sprays, smokes, baits of
    different concentrations.

    1.4.2  Pest controlled

    Jassids, bugs, aphids, flies, mosquitos, cockroaches, ants,
    millepedes and other household pests.

    1.4.3  Use pattern

    Used on pome and stone fruit, currants, grapes, vegetables, hops,
    cotton, cocoa, rice, sugar cane, ornamentals and forest crops.

    1.4.4  Unintended effects

    May have a slight fruit thinning effect if applied to orchard fruit
    shortly before blossom. It should not be sprayed any earlier than
    three weeks after petal fall.

    1.5  PUBLIC HEALTH

    Used in hospitals, factories and stables at a concentration of 0.5%
    active matter against ants, flies, fleas, cockroaches, woodlice,
    mosquitos, bedbugs and ticks.

    1.6  HOUSEHOLD USE

    Used for household control of flies, ants, aphids, mosquitos,
    cockroaches and millepedes.

    Part 2 - Toxicology and risks

    2.1  TOXICOLOGY - MAMMALS

    2.1.1  Absorption route

    Can be absorbed by inhalation, from the gastrointestinal tract and
    to a lesser extent, through the intact skin.

    2.1.2  Mode of action

    Inhibition of cholinesterase which is relatively rapidly reversible.

    2.1.3  Excretion products

    The major metabolites appear to be O-hydroxyphenyl N-methylcarbamate
    and 2-isopropoxyphenol; the latter appears in the urine as the
    glucuronide. The urine is probably the main route of excretion for
    this compound.

    Toxicity, single dose

    Oral:   LD50 Rats (M) 116.0 mg/kg
            LD50 Rats (F) 95.0 mg/kg

    Dermal:
              LD50 Rats (M & F) > 2400 mg/kg
    (at this dose, 2 out of 10 rata died in both sex groups)

    2.1.5  Toxicity, repeated doses

    Oral: Male rats were dosed daily for 30 days at 5 mg/kg and for 15
    days at 10 and 20 mg/kg. No effect was observed at 5 mg/kg. At 10
    and 20 mg/kg, fasciculations were observed immediately after dosing
    for the first 4-5 days, but after day 5, rats tolerated these doses
    with no observable signs of distress.

    Inhalation: Female rats and mice were exposed for 1 hour to
    different concentrations of aerosols, particle size 1-3 µ. A
    concentration of 210 mg/m3 killed half the rats but none of the
    mice. At the lowest concentration tested, 168 mg/m3, 3 out of 10
    rats died. Both rats and mice showed acute cholinergic signs 10-15
    minutes after exposure began.

    Cumulation of compound: Propoxur is not cumulative in body
    tissues.

    Cumulation of effect:

    Rats injected intramuscularly six days a week for two weeks at
    2 mg/kg/day (approx. 1/20 LD50), showed no cumulative effect as
    measured by plasma cholinesterase levels. (See also 2.1.5 and
    2.2.3.)

    2.1.6  Dietary stucies

    Short-term: Male and female rats were fed propoxur in their diet
    at 250, 500, 1000 and 2000 ppm for 16 weeks. At 1000 and 2000 ppm,
    food intake and body-weight were decreased in females but not in
    males. Cholinesterase activity was reduced in whole blood at dietary
    levels of over 500 ppm. At termination of the experiment,
    cholinesterase activity was markedly reduced in plasma, whole blood
    and brain at 1000 and 2000 ppm. Liver function and haematological
    tests were normal. Some necrosis and bile duct proliferation was
    observed in the liver.

    Long-term: In a two-year feeding study a dietary concentration of
    250 ppm had no ill effect on male and female rats. At 750 ppm, the
    liver weight of the female rats was increased; otherwise there were
    no adverse effects.

    2.1.7  Supplementary studies of toxicity

    Carcinogenicity: 30 mice were injected subcutaneously with
    propoxur from birth to 38 weeks of age. The total dose of propoxur
    given over this period was 9.6 mg per mouse. Urethane, which is a
    known carcinogen, was given to the second group of 30 rats as a
    positive control using the same dosing regime. The mice were then
    observed for the remainder of their life span, and at death
    post-mortem examination was performed. Incidence of tumours was
    6.25% in the group receiving only the dosing vehicle, 6.77. for
    those receiving propoxur and 45% for those receiving urethane. It
    was concluded that propoxur had no carcinogenic effect in mice.

    Teratogenicity: Rats were dosed on days 6, 8 and 11 of gestation
    with 8.3, 25 and 50 mg/kg of propoxur. The two higher doses produced
    obvious signs of maternal toxicity. No teratogenic effect was
    observed, though the highest dose caused a slight reduction in mean
    foetal weight.

    Mutagenicity: No information available.

    2.1.8  Modification of toxicity:

    No information.

    2.2  TOXICOLOGY - MAN

    2.2.1  Absorption

    Propoxur can be absorbed by inhalation and from the gastrointestinal
    tract, and to a lesser extent through the intact skin.

    2.2.2  Dangerous doses

    Single: A single oral dose of 1.5 mg/g caused blurred vision,
    sweating and vomiting and a reduction in cholinesterase activity to
    27% of the pre-dosing level. (see 2.2.5)

    Repeated: (see 2.2.5)

    2.2.3  Observations of occupationally exposed workers

    In malaria spraymen exposed to propoxur, occasional short lasting
    symptoms of overexposure have been observed. These included nausea,
    headache, sweating and weakness. These symptoms were enough to make
    a sprayman stop work with a consequent rapid recovery. Where safety
    precautions have been meticulously observed, there have been no
    recorded illnesses attributable to propoxur exposure.

    2.2.4  Observations on exposure of the general population

    Some mild reactions to propoxur were reported among the residents of
    the sprayed houses, and these were almost always associated usually
    by entering the houses during or immediately after spraying or by
    sweeping the floors with an insufficient amount of water.

    2.2.5  Observations of volunteers

    Volunteers took doses of 0.75 mg/kg or 1.0 mg/kg, split up into five
    doses at half-hour intervals. Reduction in erythrocyte
    cholinesterase activity of about 60% normal activity was observed.
    Three hours later, erythrocyte cholinesterase levels had returned to
    normal. No symptoms were observed. A single dose of 0.36 mg/kg
    caused stomach discomfort, sweating and redness of the face. A dose
    of 1.5 mg/kg caused reduction in erythrocyte cholinesterase activity
    to 27% of pre-exposure level, associated with vomiting, sweating and
    blurred vision. These symptoms lasted for one hour.

    2.2.6  Reported mishaps

    Occupational poisoning of a person by propoxur with a fatal outcome
    has not been reported. See 2.2.3 for mild symptoms of overexposure
    to propoxur.

    2.3  TOXICITY TO NON-MAMMALIAN SPECIES

    2.3.1  Fish

    Toxic (Trout 6 ppm/48 hrs - carp 20 ppm/48 hrs).

    2.3.2  Birds

    Toxic to wild birds.

    2.3.3  Other species

    Toxic to bees, livestock, game and wild animals.

    Part 3 - For regulatory authorities

    RECOMMENDATIONS ON REGULATION OF COMPOUND

    3.1  RECOMMENDED RESTRICTIONS ON AVAILABILITY

    (For definition of categories, see introductory note)

    Liquid formulations over 50% Category 3, and over 5% Category 4

    Solid formulations over 20% Category all other formulations
    Category 5

    3.2  TRANSPORTATION AND STORAGE

    Formulations in Categories 3 and 4

    Should be transported or stored in clearly labelled rigid and
    leakproof containers and away from containers of food and drink.
    Storage should be under lock and key and secure from access by
    unauthorized persons and children.

    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 Categories 3 and 4

    Protective clothing (see part 4) should be provided for those
    handling concentrates. Adequate washing facilities should be
    available close at hand. Eating, drinking and smoking should be
    prohibited during handling and before washing after handling.

    Formulations in Category 5

    No special facilities other than those for handling of any chemical
    need be required.

    3.4  DISPOSAL AND/OR DECONTAMINATION OF CONTAINER

    If not decontaminated, container must either be burned or crushed
    and buried below top-soil. Care must be taken to avoid subsequent
    contamination of water sources. Container may be decontaminated (for
    method see paragraph 4.3 on part 4). Decontaminated containers
    should not be used for food and drink.

    3.5  SELECTION, TRAINING AND MEDICAL SUPERVISION OF WORKERS

    Formulations in Categories 3 and 4

    Pre-employment medical examination for workers desirable. Workers
    suffering from active hepatic or renal disease should be excluded
    from contact. Pre-employment and periodic cholinesterase tests for
    workers desirable. Training of workers in techniques to avoid
    contact essential.

    Formulations in Category 5

    Warning of workers to minimize contact essential.

    3.6  ADDITIONAL REGULATIONS RECOMMENDED IF DISTRIBUTED BY AIRCRAFT

    All formulations

    Pilot and leaders should have special training in application
    methods and early symptoms of poisoning. Flagmen, if used, should
    wear overalls and be located well away from the dropping zone.

    3.7  LABELLING

    Formulations in Categories 3 and 4

    Minimum cautionary statement

    "Propoxur is a carbamate compound that inhibits cholinesterase. It
    is poisonous if swallowed or inhaled. 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 is a
    specific antidote and artificial respiration may be needed."

    Formulations in Category 5

    Minimum cautionary statement

    "This formulation contains propoxur, a carbamate insecticide which
    inhibits cholinesterase. It is poisonous if swallowed. Keep the
    material out of the reach of children and well away from foodstuffs,
    animal feed and their containers. If poisoning occurs, call a
    physician. Atropine is a specific antidote and artificial
    respiration may be needed."

    3.8  RESIDUES IN FOOD

    Maximum residue levels have been recommended by the Joint FAO/WHO
    Meeting on Pesticide Residues.

    Part 4 - Prevention of poisoning in man and emergency aid

    4.1  PRECAUTIONS IN USE

    4.1.1  General

    Propoxur is a carbamate insecticide of moderate toxicity which is
    quickly metabolized and therefore acts only as an acute poison. It
    can be absorbed by inhalation of the dust and also to some extent
    through the intact skin. It is important that concentrated
    formulations be washed immediately from the skin and eyes.

    4.1.2  Manufacture and formulation

    T.L.V.

    No information.

    Although volatility is low, vapour and dusts should be controlled
    preferably by mechanical means. Protective equipment for the skin
    and respiratory protection is usually necessary.

    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. The applicator
    should avoid working in spray mists and avoid contact with the
    mouth. 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 propoxur and associated with its application
    should observe the precautions described 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 propoxur.

    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 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 a 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 propoxur 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 may include excessive sweating, headache, weakness,
    giddiness, nausea, vomiting, stomach pains, salivation, tightness of
    the chest, blurred vision, slurred speech and muscle twitching.

    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, wash the affected skin with soap and water if available,
    and flush the area with large quantities of water. If swallowed,
    vomiting should be induced if the person is conscious.

    Part 5 - for medical and laboratory personnel

    5.1  MEDICAL DIAGNOSIS AND TREATMENT IN CASES OF POISONING

    5.1.1  General information

    Propoxur is a carbamate insecticide of moderate toxicity. It is
    absorbed from the gastrointestinal tract and by inhalation, and only
    to a limited extent through the intact skin. Its mode of action is
    by reversibly inhibiting acetyl cholinesterase. Erythrocyte
    cholinesterase is more inhibited than plasma cholinesterase.
    Symptoms of poisoning are short lasting and in case of occupational
    overexposure occur without a delay and at doses well below the fatal
    dose. Because of its rapid metabolism and excretion it does not
    accumulate in the tissues.

    5.1.2  Symptoms and signs

    Symptoms of poisoning include excessive sweating, headache, chest
    tightness, weakness, giddiness, nausea, vomiting, stomach pains,
    salivation, blurred vision, slurred speech and muscle twitching.
    Paresthesia and mild skin reactions have also been reported.

    5.1.3  Laboratory

    Because propoxur is a reversible inhibitor of cholinesterase,
    measurements of cholinesterase activity should be made by a method
    which minimizes the reactivation of inhibited enzyme. Erythrocyte
    cholinesterase determination is more informative than measuring
    either plasma or whole blood cholinesterase, but the enzyme will
    only be inhibited for a short time (few hours) after exposure. The
    presence of phenol metabolites of propoxur in urine is also
    indicative of exposure.

    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 or water. Since the
    symptoms of poisoning with propoxur are of short duration, atropine
    treatment is usually not necessary by the time the patient reaches a
    place where this antidote is available. Where there are manifest
    symptoms 1-2 mg of atropine sulfate (adult dose) may be given
    intramuscularly or even intravenously and repeated as necessary.
    Care should be taken to avoid over-dosage of atropine, especially
    when treating children. In extreme cases, if the patient is
    unconscious or is in respiratory distress, oxygen may be required.
    Contraindications are oximes such as pralidoxime, barbiturate and
    central stimulants of all kinds.

    5.1.5  Prognosis

    If the acute toxic effect is survived, the chances of complete
    recovery are very good.

    5.1.6  References of previously reported cases

    Mild symptoms of overexposure among malaria spraymen and residents
    of sprayed houses have been reported: Wright, J. W. et al. (1969)
    Bull Wld Hlth Org., 40, 67. See also "Safe Use of Pesticides"
    (1973), Wld Hlth Org. techn. Rep. Ser., No. 513, pp 17-18.

    5.2  SURVEILLANCE TESTS

    Due to the rapid reactivation of inhibited enzyme, determination of
    blood cholinesterase levels is of little if any practical value in
    determining when workers should be withdrawn to prevent
    overexposure. Minor complaints, such as headache and nausea, cause
    the worker to stop work and thus prevent further exposure. The
    worker quickly recovers, particularly if he washes the contaminated
    skin.

    5.3  LABORATORY METHODS

    5.3.1  Detection and assay of compound

    Because of its rapid metabolism, it is unlikely that measurable
    amounts of propoxur will be found in human tissues. A gas
    chromatographic method is described for analysis of propoxur and its
    metabolites in animal tissues and milk, see Stanly (1972).

    Estimation of excreted phenol in urine, derived from propoxur, by
    both colorimetric and chromatographic methods is described by Dawson
    et al. (1964).

    Other methods for determining residues include a spectrophotometric
    method (Gils, 1970) and a method of chromatographic analysis using
    dansyl chloride as a fluorigenic agent (Frei et al., 1972).

    5.3.2  Other tests in cases of poisoning

    Cholinesterase levels in blood are unreliable as a routine test to
    detect poisoning by propoxur. However, shortly after absorption,
    inhibition of erythrocyte cholinesterase may be demonstrated by an
    appropriate method. See Ellman, G. L. et al. (1961).

    References

    Dawson, J. A. et al. (1964) Bull Wld Hlth Org., 30, 127-134

    Ellman, G. L. et al. (1961) Biochem. Pharmacol., 7, 88-95

    Frei, R. W. & Lawrence, J. F. (1972) Chromatography, 67, (1),
    87-95

    Gils, W. F. (1970) Analyst, 95 (1126), 88-90

    Stanley, C. W. (1972) J. Agr. Chem., 20 (6), 1269-1273

See Also:
        Propoxur (ICSC)