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    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 170C with a hydrogen flame detector which gave
         detection limit of 0.1 g. 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)