DICOFOL JMPR 1974 Explanation 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. RESIDUES IN FOOD AND THEIR EVALUATION 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. RESIDUES RESULTING FROM SUPERVISED TRIALS 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 kg/ha 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. NATIONAL TOLERANCES REPORTED TO THE MEETING Country Commodities Tolerance (mg/kg) 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 APPRAISAL 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. RECOMMENDATIONS TOLERANCES mg/kg Pre-harvest interval on which recommendation 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 FURTHER WORK OR INFORMATION DESIRABLE Results of residue studies to indicate the level of residues in various fruits and vegetables following currently approved use patterns. REFERENCES 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)