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

                                                      WHO/VBC/DS/87.78

                                                      ORIGINAL: ENGLISH

                                                      Distr.: LIMITED




    DATA SHEETS ON PESTICIDES No. 78

    PROPACHLOR






         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: Herbicide

                                       Secondary Use:

                                       Chemical Group: Acetanilide

    1.0  GENERAL INFORMATION

    1.1  COMMON NAME

         Propachlor (BSI, ISO and WSSA)

    1.1.1  Identity

         IUPAC: 2-chloro-N-isopropylacetanilide

         CAS: 2-chloro-N-(1-methylethyl)-N-phenylacetamide

         CAS Reg. No.: 1918-16-7

         Molecular formula: C11H14ClNO

         Molecular weight: 211.7

         Structural formula:

    CHEMICAL STRUCTURE

    1.1.2  Synonyms

         BextonR; Bexton 4LR; Kartex AR; NiticidR; propachlore;
    RamrodR; SatecidR; CP 31393.

    1.2  SYNOPSIS

         Propachlor is a pre-emergence herbicide used against annual
    grasses and certain broad-leaved weeds. Soil persistance can range
    from 28 to 42 days post-spraying. Propachlor is slightly toxic and
    the technical product is listed in WHO Hazard Class III.

    1.3  SELECTED PROPERTIES

    1.3.1  Physical characteristics

         Propachlor is a light tan or white crystalline solid. It has a
    melting point of 67-76°C, a boiling point of 110°C at 0.03 mmHg and
    a density of 1.13 g/ml at 25°C.

    1.3.2  Solubility

         Its water solubility is 700 mg/l at 20°C; readily soluble in
    most organic solvents except aliphatic hydrocarbons.

    1.3.3  Stability

         Indefinitely stable, not sensitive to light; resistant to
    photo-decomposition.

    1.3.4  Vapour pressure

         2.3 x 10-4 mmHg at 25°C.

    1.4  AGRICULTURE, HORTICULTURE AND FORESTRY

    1.4.1  Common formulations

         These include a wettable powder (650 g a.i./kg) and granules
    (200 g a.i./kg).

    1.4.2  Pests controlled

         Annual grasses and certain broad-leaved weeds.

    1.4.3  Use pattern

         Used on maize, cotton, soyabeans, sugarcane, sorghum, sugar
    beets and vegetable crops at 3.5-5.0 kg a.i./ha.

    1.4.4  Unintended effects

         No information available.

    1.5  PUBLIC HEALTH USE

         No recommended use.

    1.6  HOUSEHOLD USE

         No recommended use.

    2.0  TOXICOLOGY AND RISKS

    2.1  TOXICOLOGY - MAMMALS

    2.1.1  Absorption

         Propachlor may be absorbed through the gastrointestinal tract;
    through the intact skin; or by inhalation of dust or spray mist.

    2.1.2  Mode of action

         Propachlor has been reported to cause dystrophic changes in
    liver and kidneys of rats, mice and rabbits at oral doses of 100-
    1800 mg/kg, accompanied by decreased enzyme activities.

    2.1.3  Excretion products

         Propachlor is metabolized via the mercapturic acid pathway.
    Eleven urinary metabolites, six of which are 2-
    methylsulfonylacetanalides have been isolated. The major fecal
    metabolite is identified as the cysteine conjugate. Rats given 14C
    propachlor orally excreted 98.6% of dose in the urine and feces
    within 48 hours.

    2.1.4  Toxicity, single dose

         Oral LD50:

         Rat                 710 mg/kg b.w.

         Mouse               290 mg/kg b.w.

         Rabbit              710 mg/kg b.w.

         Following oral and percutaneous administration of propachlor,
    increased bromosulphalein retention was seen. The liver demonstrated
    leukocyte infiltration in peripherolobular zones and focal necrosis.

         Dermal LD50:

         Rabbit              380 mg/kg b.w. (10.4% suspension in water)

         Propachlor causes severe dermatitis, ulceration and necrosis of
    the skin in rabbits and mice.

         Inhalation LC50:

         Rats                3580 mg/m3 (60% w.p.

         Inhalation of w.p. dust for four hours caused inflammation of
    tracheal mucosa, 25% mortality, and haemorrhagic secretions in lungs
    and bronchi. Effective threshold concentration was 136-456 mg/m3.

         Eye irritation: Minimum concentration of 0.01% 6.5g/kg w.p.
    in rats caused conjunctivitis.

    2.1.5  Toxicity, repeated doses

         No information available.

    2.1.6  Dietary studies

         Short term: Ninety-day rat and dog studies showed no
    observable effects at 1.3, 13.3 and 133.3 mg/kg bw/day except for a
    9% reduction in weight gain in rats at ]33.3 mg/kg bw/day.

         Four and six month studies in white rats with 1/20, 1/100 and
    1/200 of the LD50 inhibited spermatopoiesis at the phase of
    spermatid formation and caused histomorphologic changes in the
    spermaopoietic epithelium.

         Long term: No information available.

    2.1.7  Supplementary studies of toxicity

         Carcinogenicity: No information available.

         Teratogenicity: No information available.

         Reproduction: See section 2.1.6.

         Mutagenicity: No induction of recessive lethality was
    observed in  Dropsophila. Propachlor at 10 mg/kg b.w. caused
    increased aberrant metaphases (3 x control level) in mouse bone
    marrow cells.

    2.1.8  Modification of toxicity

         No information available.

    2.2 TOXICOLOGY - MAN

    2.2.1  Absorption

         Propachlor may be absorbed through the gastrointestinal tract,
    through the intact skin or by inhalation of dust or spray mist

    2.2.2  Dangerous doses

         Single: Toxicity rating 2 (Gosselin), probably oral lethal
    dose (man) 5-15 g/kg b.w.

         Repeated: No information available.

    2.2.3  Observations on occupationally exposed workers

         Exposure to propachlor for eight days caused erythematopapular
    contact eczema on hands and forearms of workers.

    2.2.4  Observations on exposure of the general population

         No information available.

    2.2.5  Observations on volunteers

         No information available.

    2.2.6  Reported mishaps

         No information available.

    2.3  TOXICITY - NON-MAMMALIAN SPECIES

    2.3.1  Fish

         Fathead minnows          96 hr TLM 0.49 rag/1
         Bluegill fingerlings     96 hr TLM 1.30 mg/1

    2.3.2  Birds

         Oral LD50 pheasants 735 mg/kg b.w.

         Oral LC50 mallard ducks 5000 mg/1

                   bobwhite quail 5000 mg/1

    2.3.3  Other species

         No information available.

    3.0  FOR REGULATORY AUTHORITIES - RECOMMENDATION ON REGULATION OF
         COMPOUND

    3.1  RECOMMENDED RESTRICTIONS ON AVAILABILITY

         (For definition of categories see Introduction to Data Sheets)

         All solid formulations over 38%, category 3

         All other solid formulations, category 4

    3.2  TRANSPORT AND STORAGE

         Formulations in all categories: Should be transported in
    clearly labelled, rigid and leakproof containers out of reach of
    children, away from food and drink. Storage should be under lock and
    key and secure from access by children and other unauthorized
    persons.

    3.3  HANDLING

         Formulations in all categories: Protective clothing to shield
    skin and eyes should be used by all handling the compound. Adequate
    washing facilities should be available at all times during handling
    and they should be close to the site of handling. Eating, drinking
    and smoking should be prohibited during handling and before washing
    hands and face.

    3.4  DISPOSAL AND/OR DECONTAMINATION OF CONTAINERS

         All formulations: Containers may be decontaminated (for
    method see paragraph 4.3 of 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 well
    below topsoil. Care must be taken to avoid subsequent contamination
    of water sources.

    3.5  SELECTION, TRAINING AND MEDICAL SUPERVISION OF WORKERS

         Formulations in all categories: Special account should be
    taken of the worker's ability to comprehend and follow instructions.
    Training of workers in techniques to avoid contact is essential.
    Pre-employment and periodic medical examinations are not required.

    3.6  ADDITIONAL REGULATIONS RECOMMENDED IF DISTRIBUTED BY AIRCRAFT

         All formulations: Pilots and loaders should have special
    training in application methods

    3.7  LABELLING

         Formulations in categories 3 and 4, minimum cautionary
    statement:
                             CAUTION - POISON

                     (skull and cross bones insignia)

         This formulation contains propachlor which is a skin and eye
    irritant, a dermal sensitizer and it may be poisonous if swallowed.
    Keep the material out of reach of children and well away from
    foodstuffs, animal feed and food containers.

    3.8  RESIDUES IN FOOD

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

    4.0  PREVENTION OF POISONING IN MAN AND EMERGENCY AID

    4.1  PRECAUTIONS IN USE

    4.1.1  General

         Propachlor is an acetanilide compound, a chlorinated tertiary
    amide of slight toxicity to mammals. It is a skin and eye irritant,
    a dermal sensitizer, and probably inhibits various enzymes at the
    cellular level. It may be absorbed by inhalation of dust or spray
    mist; through the gastrointestinal tract; and, through the intact
    skin.

    4.1.2  Manufacture and formulation - T.L.V.

         No information. 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, safety glasses, 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 mist and avoid
    contact with the mouth. Care is needed when equipment is being
    washed after use. All protective clothing should be washed
    immediately after use, including the insides of gloves. 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 the compound and associated with its
    applications should wear protective clothing and observe the
    precautions described above in 4.1.3 under "Mixers and applicators".

    4.1.5  Other populations likely to be affected

         With good application practice subject to 4.2 below, other
    populations should not be exposed to hazardous amounts of
    propachlor.

    4.2  ENTRY OF PERSONS INTO TREATED AREAS

         Unprotected persons should be kept out of treated areas until
    the compound is dry

    4.3  SAFE DISPOSAL OF CONTAINERS AND SPILLAGE

         Residues in containers should be emptied in a diluted form into
    a deep pit taking care to avoid contamination of ground water. The
    empty container may be decontaminated by rinsing two or three times
    with water and scrubbing the sides. Impermeable gauntlets should be
    worn during this work and a soakage pit should be provided for the
    rinsings. Refill container with water and allow to stand 24 hours.
    Repeat twice. Obliterate label. Spillage of propachlor 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

         Symptoms of poisoning include irritation and inflammation of
    the skin, eyes, and mucous membranes. Other effects are unknown.

    4.4.2  Treatment before a 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 water and soap, if
    available, and flush the area with large quantities of water. Take
    to a physician. If swallowed call a physician and transport to
    nearest hospital immediately.

    5.0  FOR MEDICAL AND LABORATORY PERSONNEL

    5.1  MEDICAL DIAGNOSIS AND TREATMENT IN CASES OF POISONING

    5.1.1  General information

         Propachlor is an acetanilide of moderate toxicity. It is
    absorbed from the gastrointestinal tract, by inhalation and through
    the intact skin. The mode of action is probably by inhibition of
    various hepatic enzymes at the cellular level. This chlorinated
    tertiary amide is a skin and eye irritant as well as a derma]
    sensitizer.

    5.1.2  Symptoms and signs

         Except for dermatitis, no clinical or laboratory signs of
    toxicity to man are known. Propachlor can be irritating to the skin
    and eyes as well as a derma] sensitizer.

    5.1.3  Laboratory

         No information available.

    5.1.4  Treatment

         If the pesticide has been ingested, unless the patient is
    vomiting, rapid gastric lavage should be performed with water,
    followed by activated charcoal and a mild laxative. 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. There is no specific antidote for propachlor
    poisoning.

    5.1.5  Prognosis

         If the acute toxic effect is survived, recovery will be
    uneventful.

    5.1.6  References of previously reported cases

         There have been no published reports of propachlor poisoning.

    5.2  SURVEILLANCE TESTS

         None indicated

    5.3  LABORATORY METHODS

    5.3.1  Detection and assay of compound

         Caverley, D. J. and Denney, R. C. (1978), Analyst (London)
         103 (1225), 368

         Worley, J. W.  et al. (1980), Anal. Chem. 52 (12), 1845

         Ambrus, A.  et al. (1981), J. Assoc. Off. Anal. Chem. 64(3),
         743

See Also:
        Propachlor (EHC 147, 1993)