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.