PESTICIDE RESIDUES IN FOOD - 1983
Sponsored jointly by FAO and WHO
EVALUATIONS 1983
Data and recommendations of the joint meeting
of the FAO Panel of Experts on Pesticide Residues
in Food and the Environment and the
WHO Expert Group on Pesticide Residues
Geneva, 5 - 14 December 1983
Food and Agriculture Organization of the United Nations
Rome 1985
CHLORPYRIFOS
RESIDUES
Explanation
Chlorpyrifos was reviewed by the Joint Meetings of 1972, 1974,
1975, 1977, 1981 and 1982.1 An acceptable daily intake (ADI) of
0-0.01 mg/kg b.w. was estimated by the 1982 Meeting and MRLs on a
number of food commodities, including grapes, are under consideration
in the Codex Committee on Pesticide Residues (CCPR).
Residues data following the preharvest application of
chlorpyrifos to grapes to provide protection to mature, drying and
dried vine fruit have been evaluated.
RESIDUES IN FOOD AND THEIR EVALUATION
USE PATTERN
Ripe grapes grown for the production of dried fruit are attacked
by Ephestia figulillela, Drosophila spp. and Carpophilus spp.
It has been shown that preharvest sprays with chlorpyrifos can reduce
damage. Recommended use is to spray the ripening fruit with a
200 mg/kg solution (20 g a.i. in 100 litres of water) 21 days prior to
harvest (McDonald et al. 1983).
RESIDUES RESULTING FROM SUPERVISED TRIALS
Grapes
Grape vines in Victoria, Australia, were sprayed once with
Lorsban 50 EC (50 percent chlorpyrifos) during early maturation.
Application rates of 428.5 g, 43 g and 17.0 g a.i./100 litres of water
were used to achieve target residues of 50, 5 and 2 mg/kg. Actual
initial residues were higher than expected at 73.8, 9.5 and 2.7 mg/kg.
These initial deposits vary with weight of fruit, volume of spray
required for complete coverage and retention by the surface of the
fruit.
Fruit was harvested on four occasions (0, 8, 36 and 51 days after
spraying) during the maturation period. Sampled fruit was subsampled
for analysis and dried for 21 days (the normal commercial drying
period) and again sampled for analysis. Table 1 shows the results
obtained (Sweden 1983).
1 See Annex 2 for FAO and WHO documentation.
Table 1 Residues of Chlorpyrifos in Sultanas
Application rate Preharvest interval Residue (mg/kg)
(mg/kg spray concen.) (days) at harvest on dried fruit
21 days postharvest
4 285 0 73.8 68
8 44.6 38
36 7 7
51 4.7 9
430 0 9.4 9
8 5.4 4.4
36 1.0 1.1
51 0.8 0.9
170 0 2.7 1.6
8 1.1 1.3
36 0.23 0.4
51 0.2 0.3
Table 2 Chlorpyrifos Residues in Food Commodities, Sweden
Number of samples with residues within Maximum
Food Origin No. of samples given ranges (mg/kg) residue
analysed <0.05 0.05-0.12 0.13-0.25 >0.25 (mg/kg)
Apple Sweden 286 286
Import 917 895 17 3 2 0.64
Cabbage Sweden 71 71
Import 174 173 1 0.052
Carrot Sweden 209 209
Import 217 215 1 1 0.17
Celery Sweden 8 8
Import 42 35 1 6 0.77
Cucumber Sweden 227 227
Import 353 352 1 0.060
Grapes Import 327 315 6 4 2 0.52
Grapefruit Import 148 138 6 4 0.52
Iceberg Sweden 112 112
lettuce Import 200 287 3 0.090
Lemon Import 164 163 1 0.13
Mandarin Import 292 283 8 1 0.29
Oranges Import 622 572 40 6 4 1.1
Pear Sweden 109 109
Import 455 454 1 0.23
Table 2 (con't)
Number of samples with residues within Maximum
Food Origin No. of samples given ranges (mg/kg) residue
analysed <0.05 0.05-0.12 0.13-0.25 >0.25 (mg/kg)
Pepper Import 206 198 2 4 2 0.38
(sweet)
Tomato Sweden 205 205
Import 500 496 4 0.10
Insect control has been achieved at the rate of 170 mg/kg applied
21 days before harvesting; this corresponds to a residue of
chlorpyrifos at harvest of approximately 0.5 mg/kg. There is less loss
of chlorpyrifos after harvest and there may be an increase in actual
residue content (mg/kg) owing to loss of weight of fruit on drying.
The treatment registered as good agricultural practice is
somewhat higher than the minimum treatment tested (but not as high as
the next rate).
RESIDUES IN FOOD IN COMMERCE OR AT CONSUMPTION
From 1 January 1981 to 30 April 1983 monitoring of 8 654 samples
of food commodities in Sweden gave the results shown in Table 2
(Sweden 1983). The Swedish MRLs are 0.2 for fruit and vegetables,
0.05 mg/kg for potatoes and 0.5 mg/kg for citrus fruits.
APPRAISAL
The Meeting considered data from trials in which chlorpyrifos was
applied preharvest to grapes to provide protection to mature, drying
and dried vine fruit. Residues data on the dried fruit enabled the
Meeting to estimate an MRL for dried vine fruit (based on supervised
trials on sultanas) of 2 mg/kg. This was considered suitable for the
establishment of an MRL. The Meeting confirmed that the residue should
be defined as the parent compound only.
RECOMMENDATIONS
The MRL listed below is recommended. It refers to chlorpyrifos.
Metabolites are not included. Commodity MRL (mg/kg)
Dried vine 2
fruit.
REFERENCES - RESIDUES
McDonald, G., Buchanan, G.A. & Griffiths, G.R. Insecticide
1983 application and degradation in sultana grapes grown for
drying. Pestic. Sci. 14:528-536.
Sweden. Data on chlorpyrifos residues submitted to FAO. (Unpublished)
1983