WHO/FOOD ADD./69.35



    Issued jointly by FAO and WHO

    The content of this document is the result of the deliberations of the
    Joint Meeting of the FAO Working Party of Experts and the WHO Expert
    Committee on Pesticide Residues, which met in Geneva, 9-16 December,



    Geneva, 1969


    Since the previous evaluation (FAO/WHO, 1968) additional data have
    become available and are summarized and discussed in the following
    monograph addendum.



    The 1967 Joint Meeting recommended a temporary tolerance of 0.5 ppm
    diazinon in meat (fat basis). At the Third Session of the Codex
    Committee on Pesticide Residues, the delegation of Australia proposed
    that the temporary tolerance should be increased to 0.75 ppm in meat
    (fat basis) (CCPR, 1968). It was agreed that Australia should submit
    to the FAO Secretariat data justifying an increase in the recommended
    tolerance (Australia, 1968).

    Use pattern

    Diazinon is applied in the form of emulsions and wettable powders for
    the control of ticks, lice, flies, mosquitos and sand-flies attacking
    cattle. The preparations are applied as sprays or in the form of dips
    through which the animals must swim. The concentration used for such
    treatment ranges from 0.04 per cent to 0.1 per cent.

    Residues resulting from supervised trials

    Robbins et al. (1957) showed, by using 32P- labelled diazinon, that
    the insecticide is metabolized and excreted when fed to a cow. Studies
    by Rai and Roan (1962) using conventional chemical methods as well as
    32P- labelled diazinon showed that no significant residues occurred
    in animal tissues when diazinon was administered in feed. Harrison and
    Hastie (1965) showed that there were no significant residues in the
    milk of cows and fat of sheep feeding on pasture treated by diazinon.

    Hastie (1963a and b) reviewed recent work on diazinon residues in the
    meat and fat of sheep and cattle and in the milk of cows following
    dipping or spraying. The extensive trials reported show that the
    residues of diazinon in subcutaneous fatty tissue of sheep and cattle,
    treated for parasite control, do not exceed 0.75 ppm even one day
    after treatment. However, internal fat from such animals may contain
    over 1 ppm following dipping or spraying. The average residue level
    declines rapidly following treatment but samples from individual
    animals may exceed 0.75 ppm for more than 14 days. Hastie (1965) 
    showed that standard treatment procedures resulted in residues 
    in excess of 1 ppm in the fat of sheep one day post-treatment. 
    After three days it has declined to 0.3-0.5 ppm.

    Claborn et al. (1963) showed that cattle sprayed with diazinon had
    residues of 0.75 ppm in omental fat six days after treatment but that
    the level declined rapidly thereafter. After 14 days the level had
    fallen to less than 0.1 ppm.

    Diazinon has been used for a number of years as a treatment of sheep
    and cattle against external parasites in Australia, New Zealand, South
    Africa, Argentina, Brazil and Uruguay. To a lesser degree it has been
    used in the United States of America, Canada, Mexico, and the United
    Kingdom and other countries for similar purposes.

    National tolerances

         Country             Product Tolerance (ppm)

    Australia           Meat (fat basis)                   0.75

    United States 
    of America          Meat (fat basis)                   0.75



    The meeting considered new data on residues found in cattle that had
    been treated against ectoparasites in Australia and other countries.
    Results from applications by spraying and dipping animals were
    considered. The residues from plunge treatment tend to be greater than
    those from spraying but the meeting took the view that it would not be
    practical to consider only the latter figures.

    According to Hastie (1965) the maximum residues in omental and kidney
    fat after plunge treatment were 0.9 and 0.38 ppm by the third and
    eighth day respectively.

    Figures for diazinon in objective commercial samples of fat of sheep
    in Australia were also considered. They showed only a very small
    proportion to exceed 0.75 ppm.


    The meeting confirms the previously recommended temporary tolerances
    (FAO/WHO, 1968) to be in effect until 1970 and in the case of the
    tolerance in meat (on a fat basis) recommends that the figure be
    raised from 0.5 to 0.75 ppm.

    The above temporary tolerances are to apply to raw agricultural
    products moving in commerce unless otherwise indicated. In the case of
    fruit and vegetables the tolerances should be applied as soon as
    practicable after harvest and in any event prior to actual retail to
    the public. In the case of commodities entering international trade,

    the tolerances should be applied by the importing country at the point
    of entry or as soon as practicable thereafter.


    Australia. (1968) Submission to 1968 Joint Meeting of the FAO Working
    Party of Experts and the WHO Expert Committee on Pesticide Residues.
    Prepared by the Australian Delegation to the Codex Committee on
    Pesticide Residues

    CCPR. (1968) Report of the Third Session of the Codex Committee on 
    Pesticide Residues; (ALINORM 69/24)

    Claborn, H. V. et al. (1963) Diazinon residues in the fat of sprayed
    cattle. J. Econ. Entomol., 56: 858-859

    FAO/WHO. (1968) 1967 evaluations of some pesticide residues in food
    (FAO, PL:1967/M/11/1; WHO/Food Add./68.30)

    Harrison, D. L. and Hastie, B. A. (1965) Diazinon residues in milk of
    cows, and fat of sheep after feeding on pasture treated with diazinon.
    New Zealand, J. Agr. Res., 9: 1-7

    Hastie, B. A. (1963a) Diazinon residues in sheep and cattle.
    Publication by Geigy Agricultural Chemicals, Botany, Australia

    Hastie, B. A. (1963b) Diazinon residues in fat of cattle following 
    dipping. Geigy report 63/7/162

    Hastie, B. A. (1965) Diazinon residues in sheep fat. Geigy report  

    Rai, L. and Roan, C. C. (1962) Report to NC-33 Regional Technical
    Committee from Department of Entomology, Kansas State University,
    Kansas, United States of America

    Robbins, W. F., Hopkins, T. L. and Eddy, G. W. (1957) Metabolism and 
    excretion of 32P labelled diazinon in a cow. J. Agric. Food Chem.,
    5: 509-513

    See Also:
       Toxicological Abbreviations
       Diazinon (EHC 198, 1998)
       Diazinon (ICSC)
       Diazinon (FAO Meeting Report PL/1965/10/1)
       Diazinon (FAO/PL:CP/15)
       Diazinon (FAO/PL:1967/M/11/1)
       Diazinon (AGP:1970/M/12/1)
       Diazinon (WHO Pesticide Residues Series 5)
       Diazinon (Pesticide residues in food: 1979 evaluations)
       Diazinon (Pesticide residues in food: 1993 evaluations Part II Toxicology)
       Diazinon (JMPR Evaluations 2001 Part II Toxicological)