CHLOROPROPYLATE JMPR 1972 Explanation Chloropropylate was briefly studied by the Joint Meeting in 1965 (FAO/WHO, 1965) and a comprehensive evaluation was carried out in 1968 (FAO/WHO, 1969). At this time information on several matters was requested, and available data concerning some of them is discussed. RESIDUES IN FOOD AND THEIR EVALUATION 1. Composition of the technical product No data available. 2. Terminal residues in plants, animals and their products Information given in chlorobenzilate addendum. 3. Extent of use in various countries No data available. 4. Required rates and frequencies of application, preharvest intervals and the resultant residues Table 1 summarizes data of residues from countries other than Switzerland and U.S.A. 5. Residue levels in raw agricultural products moving in commerce No data available. 6. The disappearance of residues during storage and processing Investigations by Murphy et al., (1966) showed that chloropropylate remained unchanged in apple pulp 18 days after an injection of 2 mg a.i. Field-weathered 14 day samples of apples had 89% of unchanged chloropropylate present on the surface. When using a recommended dosage rate of 60 g a.i./100 l nectarines, prunes and plums had residues below 3 ppm which reduced to 1 ppm after three weeks. Residues, which dispersed slowly, were found exclusively in the peel of citrus fruits. 7. The possible carry-over of residues into wine as a result of the treatment of grapes Residues on vine grapes were only slowly reduced. An initial value of 2 ppm decreased to 1-2 ppm after four weeks (Bartsch et al., 1971). No data available on residues in wine. TABLE 1 Chloropropylate residues in various crops1 Interval, Crop, Applications last Residue Country Rate No application (ppm) to sampling (days) fruits Apples, U.K. 0.1% of 25EC 3 28 2.17 0 2% of 25EC 1 1 0.76 0.2% of 25EC 1 27 0.92 dried fermented leaves leaves Tea, 25g a.i./100 l 1 1 19.0 14.0 Indonesia 1 19.0 4 6.7 4.8 4 4.4 7 3.6 1.8 7 7.1 <0.2 0.3 9 <0.2 50 g a.i./100 l 1 1 33.0 20.0 1 33.0 4 8.9 13.0 4 7.4 7 14.0 4.7 7 18.0 9 2.5 0.2 9 2.0 manufactured dried leaves unmixed mixed Tea, India 312 g a.i./ha 1 7 2.6 1.0 brewed tea wet leaves brew 2.05 <0.01 Cucumbers, 25 g a.i./100 l 1 1 0.86 U.K. 1 2 0.73 1 Bartsch et al., 1971. 8. Methods of residue analysis Chloropropylate residues have been determined by colorimetric methods (Benfield and Richardson, 1965; Harris, 1955) and by gas chromatography following extraction from various foods using petroleum ether (FAO/WHO, 1969), methanol (Delley et al., 1964) or mixtures of iso-propanol and benzene (Benfield and Richardson, 1965). Alumina or Florisil columns have been used (U.S Food and Drug Administration, 1968) for clean-up with various eluants. The basic alumina column clean-up was preferred because of its more consistent activity. Oily samples such as nuts, seeds and citrus peel required an additional clean-up stage (partitioning with acetonitrile) before column chromatography. The microcoulometric detector was used with a column of 1 m × 4 mm 5% G.E. XE60 on Anakrom ABS 50-60 mesh or 2 ft × ¨ in. 3% Carbowax 20M on 60/80 Gaschrom Q (FAO/WHO 1969). A 6 ft column packed with 3% XE60 on 80/100 Gaschrom Q and an electron capture detector has been found to be the more efficient system (U.S. Food and Drug Administration, 1968). Interferences from DDT and TDE were eliminated by the clean-up procedure. These materials were eluted in the benzene fraction using the Florisil column and in the hexane fraction with the alumina column. Delley et al. (1964) used glass columns packed with 2.5% Reoplex 400 on Anakrom ABS maintained at 170°C with a hydrogen flame detector which gave detection limit of 0.1 µg. Bartsch et al. (1971) give a detailed review of residue methods. APPRAISAL Some further information regarding residues of chloropropylate is now available, but the only company known to be concerned with this product (Ciba-Geigy) is no longer interested in its use. The Meeting decided, therefore, that it was not necessary to study this compound further unless this situation is changed. RECOMMENDATIONS The following recommendations made by the 1968 Joint Meeting were supported by the additional data. Temporary tolerances were changed to guideline levels. Apples, pears, citrus fruit (whole) 3 ppm Tomatoes, cantaloupes 1 ppm REFERENCES Bartsch, E., Eberle, D., Ramsteiner, K., Tomann, A. and Spindler, M. (1971) The carbinole acaricides; chlorobenzilate and chloropropylate. Residue Reviews, 39: 1-93. Benfield, C.A. and Richardson, D. (1965) Fisons Pest Control Ltd. Report No. CP/64/Anal/21. Delley, R., Friedrich, K. and Geiser, A. (1964) Geigy method ROS Nr. 2526. (unpublished) FAO/WHO. (1965) Evaluation of the toxicity of pesticide residues in food. FAO/PL/1965/10/1; WHO/Food Add./27.65. FAO/WHO. (1969) 1968 Evaluations of some pesticide residues in food. FAO/PL: 1968 M/9/1; WHO/Food Add./69.35. Harris, H.J. (1955) Colorimetric determination of ethyl 4,4'-dichlorobenzilate (chlorobenzilate) as a spray residue. J. Agr. Fd. Chem., 3: 939-941 Murphy, R., Kahrs, R. and Mattson, A.M. (1966) Dissipation of residues of chlorobenzilate and chloropropylate on apples. Geigy Chemical Corp. (unpublished) U.S. Food and Drug Administration. (1968) The determination of chlorobenzilate and chloropropylate in plant materials. Pesticide analytical manual, Vol. II, Section 120, p. 218.
See Also: Toxicological Abbreviations Chloropropylate (FAO/PL:1968/M/9/1)