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    FAO/PL:1967/M/11/1
    WHO/Food Add./68.30

    1967 EVALUATIONS OF SOME PESTICIDE RESIDUES IN FOOD

    THE MONOGRAPHS

    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 Rome, 4 - 11 December,
    1967. (FAO/WHO, 1968)

    FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
    WORLD HEALTH ORGANIZATION
    Rome, 1968

    FERBAM

    This pesticide was evaluated toxicologically by the 1965 Joint Meeting
    of the FAO Committee on Pesticides in Agriculture and the WHO Expert
    Committee on Pesticide Residue (FAO/WHO, 1965). Additional
    toxicological information, together with information for evaluation
    for tolerances, is summarized and discussed in the following monograph
    addendum.

    EVALUATION FOR ACCEPTABLE DAILY INTAKES

    Short-term studies

    Rat. A three-generation reproduction study, with two litters per
    generation, was conducted at dietary levels of ferbam of 0 and 250
    ppm, using 16 males and 16 females per dose level in each generation.
    Test animals were maintained for 3 months post-weaning before the
    first matings. No effect on fertility, gestation, viability, lactation
    or litter size was seen. No gross or histological abnormalities, as
    compared with controls, were found in animals selected for examination
    from the second litter of the third filial generation (Sherman & Zepp,
    1966).

    Comments

    Although ferbam was only found, in traces, in tissues of rats and
    dogs, storage of metabolites should be investigated as part of the
    metabolic studies needed on this class of compounds.

    In long-term studies in rats a level of 250 ppm produced no
    toxicological effect. The same level was without effect in the
    three-generation reproduction study.

    From the one-year study in dogs the daily dose of 5 mg/kg body-weight
    was without toxicological effect.

    The chemical nature of the residues of ferbam in or on the plant has
    not been ascertained. Studies are needed on the metabolism of the
    dithiocarbamates. While these data are being obtained, a temporary
    ADI, is proposed.

    TOXICOLOGICAL EVALUATION

    Level causing no toxicological effect

    Rat. 250 ppm in the diet, equivalent to 12.5 mg/kg body-weight per
    day.

    Dog. 5 mg/kg body-weight per day.

    Estimate of temporary acceptable daily intake for man

    0 - 0.025 mg/kg body-weight (alone or in combination with other
    dimethyl-dithiocarbamates.)

    This value is based on experiments carried out with ferbam and does
    not take account of chemical alterations after application.

    Further work required

    Studies of the compound in plants to determine the chemical nature of
    the residues, followed by appropriate toxicological studies.

    Results of the above work should be made available not later than 30
    June 1971 after which a re-evaluation of this compound will be made.
    The re-evaluation may be made at an earlier meeting should relevant
    information become available.

    EVALUATION FOR TOLERANCES

    USE PATTERN

    Pre-harvest treatments

    Ferbam is used primarily as a pre-harvest spray to protect a number of
    agricultural products from plant pathogens.

    RESIDUES RESULTING FROM SUPERVISED TRIALS

    Twelve applications of equal parts ziram and ferbam at 2 lb/acre to
    celery and allowing 7 days for weathering resulted in a residue of 10
    ppm (trimmed) and 4.1 ppm (trimmed and wasted). Snap beans sprayed
    with one application at 1 1/2 lb/gal/acre and a 6 day time interval
    before sampling resulted in a residue of 3.2 ppm (du Pont, 1961).


        Residues Resulting From Supervised Trials
                                                                                                
    Crop           Time interval    Treatment       Number of       Residue     Author
                       days         per acre       applications       ppm
                                                                                                

    Apples               1           3/4 lbs            1             2.55      du Pont (1957)
                        14                                            0.13           "

    Grapes               0           2                  3             5.3            "
                        26                                            2.0            "

    Cranberries         74           8 (dust)           2             0.4            "

    Apples              63           3                  4             4.6       Barry et al, 1957)
                                                                                                
    

    RESIDUES IN FOOD AT THE TIME OF CONSUMPTION

    A recent survey of five composite basic 2-week diets for males 14-19
    years old showed the presence of six dithiocarbamates with values
    ranging from 0.4 to 0.8 ppm (Duggan, Barry and Johnson, 1966). No
    residues were found in a more recent survey based upon the analyses of
    foods prepared for consumption (Duggan and Weatherwax, 1967), possibly
    because the residues decomposed rapidly as the foods were being
    prepared.

    FATE OF RESIDUES

    General Considerations

    Ferbam is only slightly soluble in water to the extent of 120 ppm.
    However, this value may not be reliable as the pH has a pronounced
    effect on its solubility (Thorn and Richardson, 1962; Thorn and
    Ludwig, 1962) as well as on its conversion to thiuram. When feeding
    the sodium salt of dimethyldithiocarbamic acid to plants three new
    antifungal compounds were found (Dekhuizen, 1961, 1964) one identified
    as a B-glucoside conjugate of dimethyldithiocarbamate (Kaslander,
    Sijpesteijn and van der Kerk, 1961), another as the conjugate with
    alanine (Kaslander, Sijpesteijn and van der Kerk, 1962) and the third
    as yet unidentified.

    METHODS OF RESIDUE ANALYSIS

    Residues have been determined by releasing either the dimethylamine
    (Barr, Clark and Jacks, 1957) or the carbon disulfide (Pease, 1957) on
    acid treatment of the sample and measuring the intensity of a coloured
    copper complex formed. Since the colour formation is critical an
    improved modification has bean outlined (Cullen, 1964). Better
    recoveries from a variety of crops have resulted from changes in the
    order of the acid decomposition procedure (Gordon, Schuckert and
    Bornak, 1967). Methods using polarographic techniques have also been
    developed (Nangniot, 1966; Vogeler, 1967).

    RECOMMENDATIONS FOR TOLERANCES

    Although some progress has been reported, neither the chemical nature
    nor the mode of action of the residues of ferbam in or on the plant
    have been ascertained and there is no specific method of analysis
    available. Accordingly, no tolerance figures can be recommended.

    FURTHER WORK

    Further work required

    Further work is required on the metabolism of ferbam in or on the
    plant to include the identification and mode of action of any critical
    intermediates, and on the development of specific methods of analysis.
    The data on this subject is required prior to 30 June 1971.

        NATIONAL TOLERANCES
                                                                                      

    Country          Tolerance, ppm                Crop
                                                                                      

    Canada                7              apples, apricots, asparagus, beans,
                 (calculated as zineb)   beets, blackberries, black-eyed peas,
                                         blueberries, broccoli, Brussels sprouts,
                                         cabbage, carrots, cauliflower, celery,
                                         cherries, collards, corn, cranberries,
                                         cucumbers, currants, dates, eggplants,
                                         gooseberries, grapes, guavas, huckleberries,
                                         kale, kohlrabi, lettuce, loganberries,
                                         mangoes, melons, mustard greens,
                                         nectarines, onions, papayas, peaches,
                                         peanuts, pears, peas, peppers, plums, fresh
                                         prunes, pumpkins, quinces, radishes,
                                         raspberries, rutabagas, spinach,
                                         squash, strawberries, summer squash,
                                         tomatoes, turnips;

    U.S.A.                7              apples, apricots, beans, blackberries,
                                         blueberries, broccoli, cabbage, cantaloupe,
                                         carrots, celery, cherries, citrus fruits,
                                         cranberries, cucumbers, gooseberries,
                                         grapes, lettuce, loganberries, peaches,
                                         pears, peppers, plums, potatoes, prunes,
                                         raspberries, squash, strawberries;

                          0.1            almonds

    Germany               1.0            leaf vegetables, fruit vegetables,
                                         pulses, fruit incl. grapes.
                                                                                      
    
    REFERENCE PERTINENT TO EVALUATION FOR ACCEPTABLE DAILY INTAKES

    Sherman, H. & Zapp, J. A. (1966) Unpublished report submitted by E.I.
    du Pont de Nemours & Co.

    REFERENCES PERTINENT TO EVALUATION FOR TOLERANCES

    Barr, H.E., Clark, P.J., Jacks, H. (1957) Determination of
    tetramethylthiuram disulfide and dimethyldithiocarbamate sprays on
    apples. New Zealand J. Sci. Tech. Sect. B,38: 425-532.

    Cullen, T.E. (1964) Spectrophotometric determination of
    dithiocarbamate residues in food crops. Anal. Chem., 36: 221-224.

    Dekhuijzen, H.M. (1961) The transformation in plants of sodium
    dimethyldithiocarbamate into other fungitoxic compounds. Nature, 191:
    198-199.

    Dekhuijzen, H.M. (1964) The systemic action of
    dimethyldithiocarbamates on cucumber scab caused by Cladosporium
    cucumerinum and the conversion of these compounds by plants. J.Plant
    Path. (Netherlands), 70: 1-75.

    Duggan, R.E., Barry, H.C., Johnson, L.Y. (1966) Pesticide residues in
    total diet samples. Science, 151: 101-104.

    Duggan, R.E. Weatherwax, J.R. (1967) Dietary intake of pesticide
    chemicals. Science, 157: 1006-1010.

    du Pont, E.I. (1957) Submission to Canada Department of Health and
    Welfare, Food and Drug Directorate.

    du Pont, E.I. (1961) Submission to Canada Department of Health and
    Welfare, Food and Drug Directorate.

    FAO/WHO. (1965) Evaluation of the toxicity of pesticide residues in
    food. FAO Meeting Rept. PL/1965/10/1; WHO/Food Add./27.65.

    FDD/Canada. (1967) Food and Drug Directorate, Canada. T.I.L. 290, 15
    Sept.

    Gordon, C.F., Schuckert, R.J., Bornak. W.E. (1967) Improved method for
    the determination of ethylenebisdithiocarbamate residues in plants,
    fruits and vegetables. J. Assoc. Off. Anal. Chem. 50: 1102-1108.

    Kaslander, J., Kaars Sijpesteijn K., van der Kerk, G.J.M. (1961) On
    the transformation of dimethyldithiocarbamate into its -glucoside by
    plant tissues. Biochim. Biophys. Acta., 52: 396-397.

    Kaslander, J., Kaars Sijpesteijn, A., & van der Kerk, G.J.M. (1962) On
    the transformation of the fungicide sodium dimethyldithiocarbamate
    into its alanine derivative byplant tissues. Biochim. Biophys. Acta,
    60: 417-419. 

    Nangniot, P. (1966) L'application des methodes electrochimiques a
    l'etude des residue de pesticides. Mededel. Landbouwhogeschool
    Opzoekingstat. Staat Gent, 31: 447-473.

    Pease, H.L. (1957) Determination of dithiocarbamate fungicide
    residues. J. Assn. Off. Agric. Chem. 40:1113-1118.

    Thorn, G.D., Ludwig, R.A. (1962) The dithiocarbamates and related
    compounds. Amsterdam, Elsevier Publ. Co., 234 p.

    Thorn, G.D., Richardson, L.T. (1962) Ferbam - Some observations.
    Mededel. Landbouwhogeschool Opzoekingstat. Staat Gent, 27: 1175-1178

    USDA. (1967) Summary of registered agricultural pesticide chemical
    uses. 2nd ed. Suppl. III.

    Vogeler, von K. (1967) Kolorimetrische und polarographische
    bestimmungen von ruckstanden in und auf pflanzen nach anwendung von
    Antracol. Pflanzenschutz-Nachrichte Bayer
    


    See Also:
       Toxicological Abbreviations
       Ferbam (ICSC)
       Ferbam (FAO Meeting Report PL/1965/10/1)
       Ferbam (Pesticide residues in food: 1996 evaluations Part II Toxicological)
       Ferbam (IARC Summary & Evaluation, Volume 12, 1976)