DICOFOL       JMPR 1974


         Dicofol was evaluated by the Joint Meeting in 1968 with a minor
    amendment in 1970 (FAO/WHO, 1969, 1971). Tolerances of 5 mg/kg were
    established for broad classes of fruit and vegetables, tea (dry
    manufactured) and hops. The Codex Committee on Pesticide Residues
    (CCPR) Meeting 1974 (Alinorm 74/24, pares. 91, 92 and 93) requested
    the Joint Meeting to reconsider the tolerances with a view to making
    more specific recommendations for fruit and vegetables and in the
    light of new data provided by member governments.

         Because of the structural relationship of dicofol to DDT, some
    delegations at the CCPR meeting in 1974 further requested a
    restriction in the use of dicofol.


    Impurities in technical dicofol

         An investigation into the content of DDE in some commercial
    formulations of dicofol has been carried out by the Food Inspection
    Service at Amsterdam in 1973 (Anonymous, 1974). From the amounts found
    in the formulations, it was calculated that the technical dicofol
    contained 1-2% of DDE as impurity.


         Two countries, namely the Netherlands and United Kingdom, have
    responded to the request for residue data to support adjustment of the
    present 5 mg/kg tolerance on fruits and vegetables. Data were supplied
    from supervised trials on apples, cucumbers, gherkins, strawberries
    and tomatoes, as summarized in Table 1.

         From these data it is noted, confirming the data supplied
    originally on supervised trials from the USA that tolerances below 5
    mg/kg would be justified for cucumbers, gherkins, strawberries and
    tomatoes under use patterns which correspond to recorded official
    recommendations. In the case of apples, however, the residue data
    indicate some variability, even under similarly described experimental
    conditions, and the new data seem to support the existing tolerance of
    5 mg/kg, particularly when it is borne in mind that dosage rates,
    pre-harvest intervals, etc. may vary in agricultural practices in
    various countries.

        TABLE 1  Dicofol residues resulting from supervised trials

                                                 Application1                Dicofol residues (mg/kg) after interval (days)
                                             Dosage       Formulation
    Crop           Country         Year      rate                         0-1       3-4       7-8       14-16     22-29     35-48     105

    Apples         Netherlands     1957      1.5-3.7      25% w.p.        1.3-                          0.2-      0.1-
                                             g/tree                       2.8                           2.0       3.0

                   Netherlands     1967-     610-750      18.5% w.p.      0.07-     0-        0-        0.08-     0.12-
                                   1970      g/ha                         1.08      0.52      0.38      0.32      0.22

                   U.K.                      600 g/ha                                                   2.5                1.02     0.30
                                                                                                        0.2                 0.16      0.12

    Cucumbers      Netherlands     1961      1.8 kg/ha    18% w.p.        0.13-     0.15-
                                                                          0.24      0.30

                   Netherlands     1961      2.3 kg/ha    smoke           0.03-     0.01-
                                                                          0.09      0.03

                   U.K.                      300-600      15% c.c2        0.16-     0.15-     1.51-
                                             g/ha                         0.88      0.73      1.82

    Gherkins       Netherlands3    1970      1.1          18.5% w.p.      0.5-      0.1-
                                             kg/ha                        1.1       0.8

    Strawberry     Netherlands3    1971      0.5          18.5% w.p.                                                        0.05-
                                             kg/ha                                                                          0.3

                   U.K.                      0.9          20% w.p.                            0.49                          0.88

    Tomatoes       Netherlands3    1973      0.4          18.5% w.p.                0.23-
                                             kg/ha                                  0.54
    1  Single application unless otherwise stated.
    2  Data include residues from both low and high volume spraying. Low volume residues are higher.
    3  By gas chromatography. All other results by colorimetric procedures.



    Country        Commodities                                      Tolerance

    Australia      Almonds, fruit (except citrus),
                   vegetables                                       5

    Canada         Almonds, apples, apricots, beans,
                   blackberries, boysenberries, cantaloupes,
                   cherries, chestnuts, crab apples,
                   cucumbers, dewberries, eggplant, figs,
                   filberts, grapes, hickory nuts, honeydew
                   melons, loganberries, muskmelons,
                   nectarines, peaches, pears, peas, pecans,
                   peppers, pimentos, plums, pumpkins,
                   quinces, raspberries, soybeans,
                   strawberries, summer squash, tomatoes,
                   walnuts, watermelons, winter squash              3

    Netherlands    Apples, pears, gherkins, cucumbers               1
                   Melons, strawberries, tomatoes                   0.5

    USA            Dried tea                                        45
                   Hops                                             30
                   Mint hay                                         25
                   Apricots, grapefruit, kumquats,
                   lemons, limes, nectarines,
                   oranges, peaches, tangerines                     10
                   Apples, beans (dry form); beans,
                   snap (succulent form); beans, lima
                   (succulent form); blackberries,
                   boysenberries, bushnuts, butternuts,
                   cantaloupes, cherries, chestnuts,
                   crab apples, cucumbers, dewberries,
                   eggplants, figs, filberts, grapes,
                   hazelnuts, hickory nuts,
                   loganberries, melons, muskmelons,
                   pears, pecans, peppers, pimentos,
                   plums (fresh prunes), pumpkins,
                   quinces, raspberries, summer squash,
                   strawberries, tomatoes, walnuts,
                   watermelons, winter squash                       5

                   Cottonseed                                       0.1


         Dicofol is an organochlorine compound, structurally related to
    DDT but with practically no insecticidal activity. Although its use
    has always been minor in comparison with other organochlorine
    compounds, it remains important in many countries especially against
    organophosphorus-resistant mites.

         Previously established tolerances of 5 mg/kg for dicofol on fruit
    and vegetables have been referred back by the CCPR to the Joint
    Meeting, requesting re-examination to determine whether tolerances on
    specific crops could be recommended.

         Information has been given to the Joint Meeting that impurities
    of DDE up to 1-2% may be present in technical dicofol. No data on DDE
    residues deriving from this source were available, but it could be
    calculated that such residues would be detectable in food for human
    consumption only in a limited number of cases, and even then in
    amounts which would be quite insignificant, when good agricultural
    practice was followed. Similarly the Meeting considered that possible
    contributions to present DDE levels in food chains from this source
    would be insignificant. On the basis of the information available
    therefore, the Meeting could make no further recommendations
    concerning the discontinuation of the use of dicofol.

         New residue data on apples, cucumbers, gherkins, strawberries and
    tomatoes were received from two countries. They were examined in
    conjunction with the data on the same crops previously filed with FAO
    and it was considered that the limit for residues on apples could not
    be set below 5 mg/kg. However, the data justified a lowering of the
    limit on cucumbers and gherkins to 2 mg/kg and on strawberries and
    tomatoes to 1 mg/kg.

         No further consideration can be given to other tolerances on
    individual crops until additional information becomes available on use
    patterns and residues in various countries.

    TOLERANCES                                 mg/kg   Pre-harvest
                                                       interval on which
                                                       is based
    Fruits (other than exceptions noted)       5
    Vegetables (other than exceptions noted)   5
    Cucumbers*                                 2       2 days
    Gherkins*                                  2       2 days
    Strawberries                               1       7 days
    Tomatoes*                                  1       3 days
    * New Tolerances



         Results of residue studies to indicate the level of residues in
    various fruits and vegetables following currently approved use


    FAO/WHO. (1969) 1968 Evaluations of some pesticide residues in        
    food. FAO/PL/1968/M/9/1; WHO/Food Add./69.35.

    FAO/WHO. (1971) 1970 Evaluations of some pesticide residues in food.
    FAO/AGP/1970/M/12/1; WHO/Food Add./71.42.

    Anonymous. (1974) Specific information to Joint Meeting from the      
    Netherlands. (Unpublished).

    See Also:
       Toxicological Abbreviations
       Dicofol (ICSC)
       Dicofol (FAO/PL:1968/M/9/1)
       Dicofol (AGP:1970/M/12/1)
       Dicofol (Pesticide residues in food: 1992 evaluations Part II Toxicology)
       Dicofol (IARC Summary & Evaluation, Volume 30, 1983)