PESTICIDE RESIDUES IN FOOD - 1984
Sponsored jointly by FAO and WHO
EVALUATIONS 1984
The monographs
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
Rome, 24 September - 3 October 1984
Food and Agriculture Organization of the United Nations
Rome 1985
PERMETHRIN
Explanation
Permethrin was evaluated at the 1979, 1980, 1981, 1982 and 1983
Meetings (FAO/WHO, 1980, 1981, 1982, 1983, 1984). 1/ Questions
referred to the JMPR by the 16th Session of the Codex Committee on
Pesticide Residues led to a review of data available on celery and
pistachio nuts from the United States.
RESIDUES IN FOOD AND THEIR EVALUATION
The permethrin residue levels reviewed below were measured by gas
chromatography using an electron capture detector, as in the previous
review (FAO/WHO, 1980).
USE PATTERN
Permethrin is registered for use at 110-220 g a.i./ha every 3-5
days to control vegetable leaf miners, cabbage loopers, granulate
cutworm, black cutworm, fall armyworm and beet armyworm, with a
pre-harvest withholding interval of three days.
RESIDUES RESULTING FROM SUPERVISED TRIALS
Celery
Residues of permethrin in celery resulting from applications of a
24 percent E.C. formulation during 1977-79 are reported in Table 1.
After three days, permethrin levels at the lower rate (110 g a.i./ha)
did not exceed 1.6 mg/kg (mean-1.1 mg/kg) and at the higher rate
(220 g a.i./ha), with one exception, did not exceed 1.9 mg/kg
(mean-1.5 mg/kg). The exception was a value of 3.2 mg/kg (Ussary,
1977a,b,c,d, 1981).
Pistachio
At 220-440 g a.i./ha, permethrin gives good control of peach twig
borers, 'Navel' orangeworms and chinchbugs.
Field trials on pistachio were conducted in the United States,
using a 24 percent E.C. formulation during the 1980-82 growing
seasons. Trees received two or three applications of permethrin at
rates of 220-880 g a.i./ha. The last application was made at 5-10
percent hull split. As expected, permethrin levels/residues in the
meats of mature pistachios were very low (Table 2). This is because
the nutmeat is completely protected from direct contact with the spray
1/ See Annex 2 for FAO and WHO documentation.
TABLE 1. Permethrin Residues in Celery, from supervised trials, United States
Rate Application Interval Residue
(g a.i./ha) Method Number Last application (mg/kg)
to sampling (days)
110 Ground 8 0 2.1
1 2.1
3 1.6
7 0.64
Ground 8 0 1.1
1 0.93
3 0.87
7 0.35
Ground 17 0 1.3
1 1.5
3 0.72
7 0.43
Ground 21 0 3.6
1 1.9
3 1.4
7 0.40
Aerial 8 0 2.8
1 2.3
4 1.2
Aerial 6 0 1.9
3 1.2
Aerial 7 1 0.99
3 0.86
220 Ground 8 0 3.3
1 4.0
3 1.7
7 1.2
Ground 8 0 2.7
1 1.8
3 1.3
7 0.87
Ground 17 0 2.8
1 3.0
3 1.8
7 1.4
Ground 21 0 3.2
1 3.5
3 1.9
7 1.4
TABLE 1. (continued)
Rate Application Interval Residue
(g a.i./ha) Method Number Last application (mg/kg)
to sampling (days)
Aerial 7 0 3.0
Aerial 7 0 2.0
3 1.2
Ground 5 0 1.8
3 1.6
Ground 11 0 4.2
3 3.2
1 The data all relate to untrimmed celery. Data have not been included where there
was reason to believe that trimming had occurred. References consulted (Ussary,
1977a,b,c,d) were reviewed at the 1979 JMPR.
TABLE 2. Permethrin Residues in Pistachio Nuts, from supervised trials, United States
Rate of No. of Interval Residue
Application Applications Last application (mg/kg)
to sampling (days)
220 2 0 0.03
1 0.02
3 0.02
5 0.01
880 2 0 0.03
(1st application) 1 0.01
440 3 0.02
(2nd application) 5 0.02
7 0.01
440 3 0 0.02
1 0.01
3 0.02
5 0.01
7 <0.01
440 2 5 0.01
7 <0.01
solution, and even the shells are largely protected by the outer hull.
It is likely that the small residues found in pistachio nutmeats were
the results of contamination (i.e. contact with treated hulls) during
sample preparation (Fitzpatrick, 1983).
APPRAISAL
As requested by the 16th Session of the CCPR, the meeting
reviewed the data supporting the proposal of 5 mg/kg as an MRL for
permethrin in celery. Additional new data were available. Good
agricultural practice requires a maximum rate of 220 g a.i./ha and an
interval of three to five days between the last application and
harvest. The meeting noted that only a relatively high number of
applications (11 per season) at the high rate resulted in a residue
at three days that exceeded 2 mg/kg. Accordingly, the meeting
re-estimated the maximum residue level following good agricultural
practice at 2 mg/kg and withdrew the estimate of 5 mg/kg.
New data enabled the meeting to estimate a maximum residue level
at the limit of determination for pistachio nuts, accepting a GAP of
up to 440 g a.i./ha and an interval of seven days between last
application and harvest. This is in full accord with prediction, since
the edible nut is fully protected from direct contact with the
pesticide.
At the request of the CCPR, the meeting reviewed the data on
permethrin on tomatoes referred to in the 1979 monographs. Although,
on occasion, the initial deposit exceeded 1 mg/kg (but was less than
2 mg/kg) the levels after three to seven days were below 1 mg/kg.
Taking into account residues on other fruiting vegetables as well, the
meeting agreed that further data were desirable if the MRL was to be
greater than 1 mg/kg.
In reviewing the data on residues in soybeans at the request of
the 16th Session of the CCPR, the meeting recognized that residues
resulting from GAP did not exceed 0.05 mg/kg in the data examined. In
considering that the edible part of the crop was fully protected, the
meeting revised its estimate from 0.1 mg/kg to 0.05 mg/kg (at or about
the limit of determination).
The meeting drew attention to the fact that the proposed MRL of
0.1 mg/kg for poultry was based on meat (muscle), whereas the figure
for carcase meat of cattle, pigs and sheep applied to sampled carcase
fat. The poultry MRL was correctly recorded in the 1980 evaluations
but incorrectly recorded as applying to carcase fat in the report.
RECOMMENDATIONS
The following estimates of MRLs recommended as suitable for use:
Commodity MRL
(mg/kg)
celery 2 (to replace celery, 5)
pistachio nuts 0.05*
soybeans 0.05* (to replace soybean 0.1)
tomatoes 1 (to replace tomatoes 2)
* at or about the limit of determination
REFERENCES
Fitzpatrick, R.D. Permethrin residues in pistachio nut meats. Report
1983 No. TMU 1206/B (Revised) submitted by ICI Americas Inc.
Agricultural Chemicals Division to FAO (Unpublished)
Ussary, J.P. Permethrin residues on celery. Report No. TMU 0341/B
1977a submitted by ICI Americas Inc. Agricultural Chemicals
Division to FAO. (Unpublished, previously reviewed by the
1979 JMPR)
Ussary, J.P. Permethrin residues on celery. Report No. TMU 0340/B
1977b submitted by ICI Americas Inc. Agricultural Chemicals
Division to FAO. (Unpublished, previously reviewed by the
1979 JMPR)
Ussary, J.P. Permethrin residues on celery. Report No. TMU 0342/B
1977c submitted by ICI Americas Inc. Agricultural Chemicals
Division to FAO. (Unpublished, previously reviewed by the
1979 JMPR)
Ussary, J.P. Permethrin residues on celery. Report No. TMU 0346/B
1977b submitted by ICI Americas Inc. Agricultural Chemicals
Division to FAO. (Unpublished, previously reviewed by the
1979 JMPR)
Ussary, J.P. Permethrin residues on celery. Report No. TMU 0622/B
1981 submitted by ICI Americas Inc. Agricultural Chemicals
Division to FAO. (Unpublished)
See Also:
Toxicological Abbreviations
Permethrin (EHC 94, 1990)
Permethrin (HSG 33, 1989)
Permethrin (ICSC)
PERMETHRIN (JECFA Evaluation)
Permethrin (Pesticide residues in food: 1979 evaluations)
Permethrin (Pesticide residues in food: 1980 evaluations)
Permethrin (Pesticide residues in food: 1981 evaluations)
Permethrin (Pesticide residues in food: 1982 evaluations)
Permethrin (Pesticide residues in food: 1983 evaluations)
Permethrin (Pesticide residues in food: 1987 evaluations Part II Toxicology)
Permethrin (JMPR Evaluations 1999 Part II Toxicological)
Permethrin (UKPID)
Permethrin (IARC Summary & Evaluation, Volume 53, 1991)