PESTICIDE RESIDUES IN FOOD - 1982
Sponsored jointly by FAO and WHO
EVALUATIONS 1982
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, 23 November - 2 December 1982
Food and Agriculture Organization of the United Nations
Rome 1983
PERMETHRIN
Explanation
Permethrin was evaluated at the 1979, 1980 and 1981 Meetings
(FAO/WHO 1980, 1981 and 1982).1 Desirable information left
outstanding from the 1981 re-evaluation included results of studies
from residues in lettuce following approved use patterns. The 1982
CCPR asked the JMPR to reconsider the recommendation of 20 mg/kg for
the maximum residue level (MRL) of permethrin on lettuce. These
results are now available as well as new data on residues permitting a
first review of permethrin on several crops for which no MRL
recommendation has been made.
RESIDUES IN FOOD AND THEIR EVALUATION
USE PATTERN
Preharvest
Almonds - Permethrin has been used in California for the control of
the navel orange-worm, Amyelois transitella. It is effective when
sprayed "high-volume" at 0.1 lb a.i./100 US gallons/acre, yielding a
treatment rate of 0.33-0.44 kg a.i./ha. "Low volume" applications of
0.44 kg a.i./ha are also effective, i.e. in 200-500 l water/ha by
ground application or in 50-100 l water/ha by aerial application. Up
to five applications per season may be necessary.
Asparagus - At rates of 0.05-0.1 kg a.i./ha, permethrin is effective
against a complex of cutworms, Agrotis spp., and against the
asparagus beetle, Crioceris asparagi. Repeat applications may be
necessary every 5-7 days.
1 See Annex 2 for FAO and WHO documentation.
Horseradish - Permethrin is effective when used as a root dip before
transplanting (at 0.1% a.i,) and as a subsequent spray at 0.1-0.2 kg
a.i./ha. The principal pest controlled is diamond back moth,
Plutella maculipennis, against which several sprays may be needed. A
preharvest withholding interval of several weeks can usually be
observed.
Grapes - In canada, multiple spray applications are used at rates
up to 0.15 kg a.i./ha (0.6 kg Ambush 25WP/ha or 0.25 kg Ambush
25WP/1000 l) to within 21 days of harvest for control of grape berry
moth and leafhopper.
Olives - Permethrin is effective against olive moth, Prays
olea, and olive fly, Dacus oleae. The former is an early season
pest, occurring before fruit formation. The latter is a later season
pest and applications to control this pest are most likely to
influence the permethrin residue levels found in the olives.
Sunflower seed - At 0.05-0.1 kg a.i./ha, permethrin is effective
against cutworms, (Agrotis spp., Euxoa spp. and Spodoptera spp.)
and against the sunflower seed weevil, Desmoris constrictus. The
higher rate of 0.1-0.2 kg a.i./ha is required against the sunflower
head moth, Homoeosoma electellum. Several applications per season
may be necessary for control of this pest complex. A preharvest
withholding interval of four weeks can usually be observed.
RESIDUES RESULTING FROM SUPERVISED TRIALS
Preharvest
Almonds - Data are available from a total of eleven residue trials
conducted in California, U.S in the period 1979-81. The trials
encompassed both ground and aerial applications. Permethrin was
applied at a standard rate of 0.1 lb/100 US gallons of spray at
300-400 US gallons of spray/acre during ground applications, or at
0.4 lb a.i./acre (0,44 kg a.i./ha) during aerial applications.
Permethrin levels in the nuts harvested during the three weeks
following the last application were normally below 0.05 mg/kg, except
in one trial, in which levels up to 0.38 mg/kg were recorded, but
where the possibility of contamination cannot be excluded (Table 1)
(Pearson 1982; Ussary 1980a, 1981a).
Asparagus - Four residue trials were conducted in 1979-81 in three
separate areas of the U.S., in which a 24% EC formulation was applied
by ground equipment at 0.11 or 0.22 kg a.i./ha on up to six occasions.
Asparagus spears were harvested 1-3 days later. Permethrin levels in
these spears were consistently below 1 mg/kg (Table 2) (Fitzpatrick
1982a; Ussary 1980b).
Table 1. Permethrin Residues in Almond Nuts, U.S., 1979-81
Interval between
Application Spray last application Permethrin residue levels
Rate Volume Number of How and harvest (mg/kg) in nuts 1
(kg a.i./ha) (l water/ha) Applications Applied (days)
0.39 3150 3 Ground 27 0.02
0.39 3150 2 Ground 44 0.07
0.39 3150 1 Ground 99 0.02
0.44 3600 3 Ground 0 0.07
0.44 3600 3 Ground 7 0.04
0.44 3600 3 Ground 14 0.04
0.44 3600 3 Ground 21 0.04
0.44 3600 3 Ground 0 0.38
0.44 3600 3 Ground 8 0.08
0.44 3600 3 Ground 14 0.09
0.44 3600 3 Ground 21 0.13
0.44 3600 2 Ground 6 0.24
0.44 3600 2 Ground 14 0.25
0.44 270 2 Aerial 7 <0.05
0.44 270 2 Aerial 14 <0.05
0.44 450 5 Ground 7 0.02
0.44 3600 5 Ground 7 0.01
0.44 3600 5 Ground 0 0.03
0.44 3600 5 Ground 1 0.02
0.44 3600 5 Ground 4 0.01
0.44 3600 5 Ground 8 0.02
0.44 3600 5 Ground 15 0.01
0.44 3600 5 Ground 22 <0.01
Table 1. (con't)
Interval between
Application Spray last application Permethrin residue levels
Rate Volume Number of How and harvest (mg/kg) in nuts 1
(kg a.i./ha) (l water/ha) Applications Applied (days)
0.44 2700 5 Ground 8 <0.01
0.33 2700 5 Ground 7 0.01
0.33 2700 5 Ground 12 0.05
0.44 270 6 Aerial 7 0.01
0.44 270 5 Aerial 6 0.01
1 24% EC formulation used. All results corrected for % recovery.
Table 2. Permethrin Residues on Asparagus, U.S.
Interval between Residues of
Location and Rate of Spray volume Number of last application permethrin 1
Year application (l water/ha) applications and harvest [days) (mg/kg)
(kg a.i./ha)
Michigan 0.11 180 4 3 0.44
1979
California 0.22 230 1 1 0.11
1981 3 0.06
6 1 0.82
3 0.21
Michigan 0.22 270 4 1 0.43
1981 3 0.05
Washington 0.22 650 1 1 0.61
State 3 0.10
1981
2 1 0.69
3 0.11
6 1 0.32
3 0.14
1 24% EC formulation used. Results corrected for % recovery.
Horseradish - Seven trials were conducted in the U.S. in 1979, in
which roots were dipped in a 0.1% a.i. emulsion for 30 minutes 4-17
days before transplanting. Three foliar sprays of 0.22 kg a.i./ha were
applied subsequently. In all cases, a 24% EC formulation was used. The
resulting permethrin levels in the roots were consistently below
0.5 mg/kg (Table 3) (Ussary 1981b).
Leeks - Data resulting from trials on leeks in the Netherlands were
reviewed by the 1979 Meeting. Permethrin was applied "high volume" at
0.005% either once or twice. Residue levels in leeks harvested 6-7
days after the last application were in the range of up to 0.31 mg/kg,
with a mean of eight results of 0.12 mg/kg. At the time, the 1979
Meeting also took note of permethrin residue levels in spring onions
in deciding that an MRL value of 5 mg/kg would be appropriate. The
1982 Meeting of the Codex Committee on Pesticide Residues requested
that the Joint Meeting re-examine the data. No new residue information
is available for review. The available data on leeks taken in
isolation show values consistently below 0.5 mg/kg.
Lettuce - Considerable data were available for review by the 1979
Meeting from trials in Germany, Netherlands, U.K. and U.S. Further
data are now available from trials in Denmark, U.K. and U.S., yielding
a total of more than 400 pieces of individual data in all. The total
available data are summarized in Table 4 (Fujie 1976,1979; Swaine and
Sapiets 1979a, b; Swaine et al 1980a, b, c, 1981; Ussary 1975-77,
1978, 1980c). Additional data from trials in U.S. are given more fully
in Tables 5 and 6.
Grapes - At the 1982 CCPR, the Canadian delegation noted that the
proposal of 1 mg/kg was not adequate to cover the use of permethrin on
grapes in Canada. Residue data from use pattern applications in trials
in five sites in Canada confirmed that residues up to 2 mg/kg can
occur (Table 7).
Olives - Two trials were conducted in Spain in 1976. Permethrin was
applied three time at a rate of 0.25 or 0.5 g a.i./tree on each
occasion. These rates are equivalent to approximately 0.025 and
0.05 kg a.i./ha. Olives were harvested immediately before the last
application and then during the following three weeks. Permethrin
levels in olives declined relatively slowly. However, the values were
consistently below 1 mg/kg (Table 8) (Burke and Hulm 1979).
Sunflower seed - A 24% EC formulation was used in 12 trials in the
U.S, in 1978-80. Applications were by air in eight of the trials and
by ground in the other four. Samples of mature seeds were harvested
13-44 days after last application when permethrin levels were below
1 mg/kg in all but one instance (1.6 mg/kg) (Table 9) (Fitzpatrick
1982b; Ussary 1982b).
Table 3. Permethrin Residues in Horseradish Roots, U.S., 1981
Lowest Highest
Rate of Interval between residue residue Mean
application 1 Number of last spraying and determined determined residue
(kg a.i./ha) applications harvest (days) (mg/kg) (mg/kg) (mg/kg) 4
0.22 2 3 23-26 0.073 0.31 0.29 (3)
3 34 <0.01 0.15 0.056 (3)
3 40 - - 0.074 (1)
0.44 3 3 23 - _ 0.45 (1)
1 24% EC formulation used.
2 The horseradish sets were dipped for 30 minutes in a 0.1% emulsion of permethrin 4-17 days before planting.
3 The horseradish sets were dipped for 30 minutes in a 0.2% emulsion of permethrin 7 days before planting.
4 All results corrected for % recovery. Figures in parentheses are the numbers of results upon which the means are based.
Table 4. Permethrin Residues on Lettuce
Spray Interval Lowest Highest
Country and Formulations Rate of volume Number of between last residue residue Mean
Year used application (l water/ applications spraying and determined determined residue
(kg a.i./ha) ha) harvest (days) (mg/kg) (mg/kg) (mg/kg) 1
Denmark 25% EC 0.15 1 1 6.8 (1)
1980 3 7.9 (1)
(indoor) 5 6.7 (1)
7 6.7 (1)
14 4.5 (1)
0.375 1 1 14 (1)
3 11 (1)
5 9.7 (1)
7 6.7 (1)
14 6.3 (1)
Germany 25% EC 0.03 600 3 0 0.58 1.4 0.88 (3)
1977 1 0.84 1.9 1.3 (3)
(outdoor) 4 0.42 1.8 0.98 (3)
7 0.22 0.45 0.35 (3)
10 0.19 0.28 0.24 (3)
14 0.03 0.08 0.06 (2)
Holland 25% EC 0.05-0.075 1000-1500 1 0 3.8 4.4 4.1 (3)
1977 7 1.9 2.8 2.0 (3)
(indoor) 17 1.1 1.6 1.3 (3)
21-22 <0.01 1.5 0.66 (11)
28 0.31 0.45 0.39 (3)
35 0.17 0.20 0.18 (3)
Table 4. (con't)
Spray Interval Lowest Highest
Country and Formulations Rate of volume Number of between last residue residue Mean
Year used application (l water/ applications spraying and determined determined residue
(kg a.i./ha) ha) harvest (days) (mg/kg) (mg/kg) (mg/kg) 1
UK 1.25% EC 0.10-0.12 2500-300 1 0-3 0.26 4.3 2.1 (5)
1978 0.22-0.24 " 1 0-3 0.80 5.4 3.6 (5)
(outdoor)
UK 25% EC 0.05 520 1 0 2.5 (1)
1979 1 3.3 (1)
(indoor.)
0.10 520 1 0 2.3 (1)
1 3.3 (1)
UK 25% EC 0.05 700 2 0 0.27 1.3 0.68 (5)
1980 1 0.03 0.90 0.50 (4)
(outdoor) 3 0.01 0.54 0.39 (4)
7 0.01 0.32 0.14 (4)
0.10 700 2 0 0.22 2.8 1.5 (5)
1 0.36 5.1 2.0 (4)
3 0.11 1.8 0.84 (4)
7 0.01 1.2 0.52 (4)
1.25% EC 0.05 1250 2 0 0.20 1.4 0.54 (5)
1 0.13 1.8 0.62 (4)
3 0.01 1.4 0.51 (4)
7 0.01 0.23 0.12 (4)
0.10 1250 2 0 0.34 1.9 0.95 (5)
1 0.05 3.1 0.98 (4)
3 0.01 1.4 0.51 (4)
7 0.01 0.90 0.38 (4)
Table 4. (con't)
Spray Interval Lowest Highest
Country and Formulations Rate of volume Number of between last residue residue Mean
Year used application (l water/ applications spraying and determined determined residue
(kg a.i./ha) ha) harvest (days) (mg/kg) (mg/kg) (mg/kg) 1
UK 25% EC 0.05 1 0 0.77 (1)
1980 3 0.35 (1)
7 0.18 (1)
0.10 1 0 0.90 (1)
3 0.66 (1)
7 0.40 (1)
USA 25% EC 0.05 160-560 2-6 1 0.14 0.18 0.16 (3)
1975-9 40% EC for ground 3 0.02 0.22 0.12 (5)
(outdoor) spraying 7 <0.01 0.13 0.06 (5)
or 13-14 <0.01 0.04 0.02 (5)
27-90
0.150-140 2 during 2-10 0-1 <0.01 5.7 0.77 (21)
aerial 3-4 <0.01 3.5 0.55 (14)
spraying 7 <0.01 1.2 0.24 (15)
0-14 <0.01 0.25 0.06 (8)
210-280 2 2-15 0-1 0.10 17 3.5 (64)
2-4 0.06 16 3.8 (47)
5-7 <0.01 6.8 1.5 (25)
13-14 <0.01 0.36 0.15 (10)
1 Figures in parentheses are the numbers of results upon which the means are based. All results are corrected for % recovery.
2 Indicates effective use rates.
Table 5. Permethrin Residues in Lettuce, U.S.
Interval from
Spray last application Permethrin residue (mg/kg) 1
Location Number of volume to
and year Formulation applications (l water/ha) harvest (days) 0.5-0.55 kg/ha 0.1-0.11 kg/ha 0.2-0.22kg/ha Notes
California 24% EC 2 540 3 0.15 0.26
1976 7 <0.02 0.04
New York 24% EC 2 450 1 0.44 0.91
1975 3 0.33 1.1
6 0.28 0.61
8 0.36 0.19
Arizona 24% EC 6 270 0 0.25
1975 1 0.18
3 0.19 0.47 0.06
7 0.13 0.25 0.54 Trimmed
14 0.02 0.06 0.08 heads
California 24% E C 2 450 1 0.69
1975 3 0.07 0.03 0.27
7 <0.01 0.02 0.08
13 <0.01 <0.01 <0.01
California 24% EC 8 270 1 0.04,0.04 0.19
1976 3 0.07,0.10 0.46
7 0.03,0.06 0.10
Table 5. (con't)
Interval from
Spray last application Permethrin residue (mg/kg) 1
Location Number of volume to
and year Formulation applications (l water/ha) harvest (days) 0.5-0.55 kg/ha 0.1-0.11 kg/ha 0.2-0.22kg/ha Notes
California 24% EC 4 450 0 0.36
1975 1 0.18 0.53 0.73
3 0.02 0.02 0.06
7 0.04 0.15 0.07
14 0.04 0.25 0.33
Arizona 24% EC 6 510 0 0.38 3
1976 1 0.15 2 0.46 3
7 0.17 2 0.26 3 Trimmed
14 0.03 2 0.12 3 heads
California 24% EC 2 270 0 0.46
1976 and 1 0.13 0.13
540 3 0.02 0.15
7 0.04 0.02
14 <0.01 0.02
Arizona 24% EC 4 270 1 0.16 0.33 0.48
1976 3 0.09 0.23 0.27
7 0.07 0.14 0.22
14 0.02 0.04 0.07
Arizona 24 % EC 3 270 1 0.14 0.45 0.71
1975 3 0.22 0.29 0.50
7 0.05 0.19 0.34
14 0.02 0.12 0.35
Table 5. (con't)
Interval from
Spray last application Permethrin residue (mg/kg) 1
Location Number of volume to
and year Formulation applications (l water/ha) harvest (days) 0.5-0.55 kg/ha 0.1-0.11 kg/ha 0.2-0.22kg/ha Notes
California 24% EC 9 270 0 0.11
1976 1 0.10 0.34
4 <0.05 0.24
7 <0.05 0.15
10 <0.05 0.21
Arizona 24% EC 10 160 0 0.20 0.39
1977 1 0.30 0.38
3 0.20 0.24 Trimmed
7 0.20 0.36 heads
California 24% EC 5 190 0 <0.05
1977 1 <0.05
3 <0.05
7 <0.05
Texas 24% EC 4 70 0 <0.05
1977 1 <0.05
3 <0.05
7 <0.05
Arizona 24% EC 9 60 0 0.30
1977 1 0.10
3 0.30
7 nd
Table 5. (con't)
Interval from
Spray last application Permethrin residue (mg/kg) 1
Location Number of volume to
and year Formulation applications (l water/ha) harvest (days) 0.5-0.55 kg/ha 0.1-0.11 kg/ha 0.2-0.22kg/ha Notes
Arizona 24% EC 10 225 1 3.9
1978
Arizona 24% EC 10 225 1 6.2
1978
California 24% EC 8 270 1 0.55
1978
Arizona 24% EC 10 90 0 8.7
1979 3 8.0
7 6.8
California 24% EC 8 180 1 1.5 - Untrimmed
1979 heads
California 24% EC 10 90 0 2.4
1979 3 0.66
7 0.92
24%EC 12 90 0 1.3
3 1.5
7 1.0
California 24% EC 10 270 1 4.4
1979 and
560
Table 5. (con't)
Interval from
Spray last application Permethrin residue (mg/kg) 1
Location Number of volume to
and year Formulation applications (l water/ha) harvest (days) 0.5-0.55 kg/ha 0.1-0.11 kg/ha 0.2-0.22kg/ha Notes
California 24% EC 9 180 1 2.1
1979
California 24% EC 8 560 1 3.3
1979
Florida 24% EC 11 270 1 1.3 3.3
1978
New York 24% EC 10 90 1 1.9
1979
Arizona 40% EC 15 45 0 8.6,10,
1978 11, 11
Arizona 40% EC 15 90 0 15, 17
1978 3 16, 16
California 40% EC 15 90 0 1.3,1.5
1978 3 1.1,0.79
California 40% EC 15 320 0 14,9.7
1978 3 11,8.8
California 40% EC 15 45 0 1.7,2.2
1979 3 0.33,0.40
California 40% EC 15 135 0 8.1,5.8
1978 3 5.3,7.0
Table 5. (con't)
Interval from
Spray last application Permethrin residue (mg/kg) 1
Location Number of volume to
and year Formulation applications (l water/ha) harvest (days) 0.5-0.55 kg/ha 0.1-0.11 kg/ha 0.2-0.22kg/ha Notes
California 40% EC 15 320 0 5.2,6.4
1978 3 4.7,3.8
California 40% EC 15 150 0 5.1,6.7
1978 3 3.4,3.0
Arizona 40% EC 15 270 0 6.5,9.9 Untrimmed
1976 3 7.2,7.0 heads
California 40% EC 15 230 0 4.9,12
1976 3 8.3,6.4
Arizona 40% EC 15 320 0 1.7,2.3
1976 3 2.6,2.1
1 Results corrected for % recovery.
2 0.14 kg a.i./ha rate.
3 0.28 kg a.i./ha rate.
Table 6. Permethrin Residues in Lettuce, U.S.
Rate of Interval between Permethrin residues (mg/kg) in
application last application
(g a.i./ha) and harvest (days) Wrapper Leaves Trimmed Heads
200 3 10 0.27
7 9.0 0.22
14 5.4 0.07
275 7 4.5 0.26
14 3.1 0.12
200 1 47 0.71
3 9.2 0.50
7 9.6 0.34
14 6.3 0.35
200 1 31 0.19
3 21 0.46
7 19 0.10
200 1 13 0.73
3 8.8 0.06
7 6.8 0.07
14 8.3 0.33
200 1 11 0.69
3 18 0.27
7 8.9 0.08
13 2.8 <0.01
220 0 6.2 0.39
1 5.4 0.38
3 4.9 0.24
7 4.6 0.36
110 1 3.0 0.30
110 0 3.9 <0.01
1 3.6 <0.01
3 2.7 <0.01
Table 6. (con't)
Rate of Interval between Permethrin residues (mg/kg) in
application last application
(g a.i./ha) and harvest (days) Wrapper Leaves Trimmed Heads
110 0 2.5 <0.01
1 2.7 <0.01
3 2.3 <0.01
7 1.2 <0.01
220 1 5.5 0.10
3 3.8 0.30
Other crops - Data from Finland (Table 10) on oilseed rape, tomato,
cucumber and currants confirmed the estimates of maximum residue
levels for these crops. It was noted however, that residues on
currants could exceed the limit under discussion by the Codex
Committee.
FATE OF RESIDUES
On Processing and Cooking
Data on the fate of residues on processing of sunflower seeds are
from a trial in the U.S. in which a sunflower field was treated
aerially five times with permethrin at the rate of 0.22 kg a.i./ha.
The seeds were harvested for processing into hulls, solvent extracted
meal and crude oil. The crude oil was further processed into refined,
bleached, deodorized oil, soapstock and deodorizer distillates. These
commodities were analysed for residues of permethrin (Table 11).
Residues in hulls were only marginally higher than residues in whole
seed, and residues in crude oil are somewhat lower. Refining further
reduced the level of residues in oil (Ussary 1982).
Data on the effects of washing are from a study in the UK in
which lettuce was sprayed with a 25% EC formulation of permethrin at
0.1 kg a.i./ha. Heads of lettuce harvested three days later were
quartered, the opposite quarters being bulked; half of the lettuce
remained unwashed whereas the other half was washed with cold water
before analysis. Residue analysis for permthrin demonstrated that the
effect of washing was to reduce the mean of a three-day old weathered
residue from 0.66 mg/kg to 0.24 mg/kg, i.e. to less than 50% (Swaine
et al 1980a).
Table 7. Permethrin Residues in Grapes, Canada
Application
Rate Interval Residues (mg/kg) 1
Location (kg a.i./ha) No. Formulation (days) cis trans total
Stoney Creek,
Ontario 0.07 5 25 WP 21 0.04
0.29
34 0.16 0.26 0.42
40 0.22 0.29 0.51
6 34 0.12 0.14 0.26
0.14 0.17 0.31
7 0 1.88;2.90
1 1.93;1.90
3 2.99;1.90
5 1.92;1.20
7 0.70;1.30
14 0.78;0.97
21 1.15;0.34
0.10 7 25 WP 0 1.98;1.87
1 2.28;2.90
3 3.03;2.00
5 2.37;1.20
7 1.65;1.33
14 1.67;1.14
21 1.18;0.97
Table 7. (con't)
Application
Rate Interval Residues (mg/kg) 1
Location (kg a.i./ha) No. Formulation (days) cis trans total
Stoney Creek,
Ontario 0.14 5 25 WP 21 0.10
0.59
28 0.09
0.45
34 0.61 0.83 1.44
40 0.36 0.44 0.08
6 34 0.17 0.21 0.38
0.31 0.32 0.63
7 0 2.17;3.90
1 2.15;3.92
3 3.90;0.99
5 2.77;1.22
7 1.98;1.35
14 1.96;1.92
21 1.98;1.18
Untreated <0.01-0.05
Vineland,
Ontario 0.14 1 25 WP 0 0.92
1 0.49
3 0.41
7 0.13
14 0.13
21 0.17
Untreated 0.01
Table 7. (con't)
Application
Rate Interval Residues (mg/kg) 1
Location (kg a.i./ha) No. Formulation (days) cis trans total
Jordan,
Ontario 0.14 1 25WP 7 0.6
14 0.5
21 0.38
Untreated 0.06-0.08
Oliver,
British Columbia 0.20 1 25 WP 35 0.41
untreated <0.01
Summerland,
British Columbia 0.20 1 25 WP 38 0.36
59 0.25
untreated <0.01
1 Residue levels were corrected for recovery.
Table 8 Permethrin Residues in Olives, Spain, 1976 1
Application Interval between Lowest Highest Mean
rate 2 Number of last spraying residue residue residue
(g a.i./tree) applications and harvest determined determined (mg/kg)
(days) (mg/kg) (mg/lg)
0.25 2 (1 hour before 0.28(1)
final spray)
3 0 0.26 0.61 0.44(2)
3 0.25(1)
7 0.16 0.26 0.21(2)
14 0.25 0.42 0.34(2)
21 0.19 0.30 0.25(2)
0.5 2 (1 hour before 0.66(1)
final spray)
3 0 0.51 0.72 0.62(2)
3 0.59(1)
7 0.46 0.63 0.55(2)
14 0.46 0.71 0.59(2)
21 0.46 0.63 0.55(2)
1 All results are corrected for % recovery. Figures in parentheses are numbers of
results on which means are based.
2 25% EC formulation used.
Data on the fate of permethrin residues on cooking are from a
study in which apples and tomatoes (whole commodity) were accurately
fortified with permethrin at 1 mg/kg and 0.1 mg/kg respectively.
Triplicate samples of each crop were analysed for residues of
permethrin both before and after cooking. For apples, the cooking
process involved baking the whole fruit for 45 minutes at 165°C. For
tomatoes, it involved frying the sliced commodity for 2-3 minutes in a
small amount of vegetable oil. Both the tomato and oil were recovered
for analysis. Residues of permethrin on apples and tomatoes, as
individual cis and trans isomers before and after cooking, are
shown in Tables 12 and 13. Results indicate that permethrin levels do
not alter during baking or frying. The ratios of the cis and
trans isomers remained essentially constant during the apple baking.
The measured residues on fried tomatoes indicate a very small isomer
ratio change towards cis enrichment, which is not significant
(Swaine and Rippington 1982).
Table 9. Permethrin Residues in Sunflower Seeds, U.S., 1978-80 1
Spray Interval between
Method of Application volume Number of last application Permethrin
Location application rate (l water/ applications and harvest residues
(kg a.i./ha) ha) (days) (mg/kg)
Colorado ground 0.11 230 2 13 <0.05
0.22 230 <0.05
South Dakota aerial 0.11 4 28 <0.05
Texas aerial 0.22 18 4 25 1.6
Minnesota aerial 0.22 4 28 0.02
Minnesota aerial 0.22 4 28 0.95
Texas aerial 0.11 18 5 20 0.31
Texas ground 0.11 36 2 28 0.56
0.22 36 0.56
North Dakota aerial 0.11 45 3 46 <0.05
Texas aerial 0.11 18 2 43 0.24
Colorado ground 0.11 180 1 44 <0.05
0.22 180 <0.05
Colorado aerial 0.11 45 2 44 <0.05
0.22 45 <0.05
Nebraska aerial 0.22 27 5 28 0.58
1 Results are corrected for % recovery. 24% EC formulation used.
Table 10 Permethrin Residues in Crops, Finland
Application Interval from Interval from
rate last application last application Residue
Crop (a.i.) to harvest (days) to analysis (days) (mg/kg)
Oilseed rape 0.25 kg/ha 89 149 seeds nd 0.1
(sprayed)
Oilseed rape 0.15 kg/ha 87 215 seeds nd 0.1
(sprayed)
Tomato 13 mg/plant 4 4 0.4
(sprayed)
(plastic
greenhouse)
" " 7 7 0.5
Cucumber " 4 4 0.1
Black currant 0.07 g/bush 29 30 2.7
(sprayed)
" " 14 14 4.3
" " 7 7 3.2
Red currant 0.18 g/bush 29 30 7.7
(sprayed)
" 0.15 g/bush 14 14 6.5
(sprayed)
" 0.18 g/bush 7 7 7.1
(sprayed)
Table 11. Permethrin Residues in Sunflower Seed Process
Fractions 1
Process Fractions Permethrin Residues
(mg/kg)
Whole Seed 0.58
Hulls 0.85
Meal 0.04
Crude Oil 0.41
Refined, bleached, deodorized oil 0.34
Deodorizer distillates 0.56
Soapstock 0.14
1 Values corrected for % recoveries.
Table 12. The Effect of Baking Apples on Permethrin Residues 1
Sample Permethrin residues (mg/kg)
cis isomer trans isomer cis:trans isomer total
Uncooked I 0.433 0.641 40.3:59.7 1.07
" II 0.390 0.586 40:60 0.98
" III 0.465 0.708 39.6:60.4 1.17
Uncooked mean 0.429 0.645 40:60 1.07
Baked I 0.399 0.618 39.2:60.8 1.02
" II 0.384 0.579 39.9:60.1 0.96
" III 0.401 0.608 39.4:60.6 1.02
Baked mean 0.395 0.602 40:60 1.0
1 Fortified at 1.0 mg/kg.
Table 13. The Effect of Frying Tomatoes on Permethrin Residues
Sample Permethrin residues (mg/kg)
cis isomer trans isomer cis:trans isomer total
Uncooked I 0.039 0.058 40.2:59.8 0.10
II 0.035 0.051 40.7:59.3 0.09
III 0.036 0.054 40:60 0.09
Uncooked mean 0.037 0.054 40:60 0.09
Fried I 0.038 0.051 42.7:57.3 0.09
II 0.036 0.047 43.4:56.6 0.08
III 0.040 0.057 41.2:58.8 0.10
Fried mean 0.038 0.051 42:58 0.09
1 Fortified at 0.1 mg/kg.
NATIONAL MAXIMUM RESIDUE LIMITS
In addition to the national MRLs reported to earlier Meetings,
additional ones have been established in the U.S. The full list is
given in Table 14.
Table 14. Maximum Residue Limits, U.S.
Crop mg/kg
Cottonseed 0.5
Broccoli 1.0
Brussels sprouts 1.0
Cabbage 6.0
Celery 5.0
Cauliflower 1.0
Lettuce (head) 20.0
Pears 0.05
Potatoes 0.05
Cattle, fat 0.5
Cattle, meat 0.05
Cattle, meat by-products 0.3
Eggs 0.05
Goats, fat 0.5
Goats, meat 0.05
Goats, meat by-products 0.3
Table 14. (con't)
Crop mg/kg
Pigs, fat 0.5
Pigs, meat 0.05
Pigs, meat by-products 3.0
Horses, fat 0.5
Horses, meat 0.05
Horses, meat by-products 0.3
Milk fat (reflecting 0.25 mg/kg in whole milk) 1.25
Poultry, fat 0.05
Poultry, meat 0.05
Poultry, meat by-products 0.05
Sheep, fat 0.5
Sheep, meat 0.05
Sheep, meat by-products 0.3
APPRAISAL
The use pattern for permethrin on lettuce varies among countries.
For example, the U.S. has established a preharvest withholding
interval of one day on lettuce. New Zealand has set two days for
greenhouse fruit and vegetables. Belgium has set two days for lettuce
grown under glass and seven days for the outdoor crop. France has
adopted 15 days and The Netherlands 21 days.
The data reviewed by the 1979 Meeting from trials in The
Netherlands indicated a maximum residue of 1.5 mg/kg 21 days after
application at effective use rates. The Netherlands has established an
MRL of 2 mg/kg. No residues data were available for review from
Belgium, where the approved application rate is 0.025-0.0375 kg
a.i./ha. However, the data from Denmark, Germany, The Netherlands and
the U.K. support the view that permethrin levels in lettuce in Belgium
would be below 2 mg/kg and Belgium has established an MRL of 1 mg/kg.
In the U.K., rates up to 0.05 kg a.i./ha are used, and the data would
suggest that a [illegible text] 2 mg/kg would cover most eventualities.
The use pattern registered in the U.S. is for rates of
0.055-0.11 g a.i./ha against cabbage looper, Trichopulsia ni, and
for rates of 0.11-0.22 kg a.i./ha against beet army-worm, Laphygma
exigua, and corn earworm, Heliothis armigera. The registrations
incorporate a one-day preharvest interval. These rates are generally
higher than those usually required in western Europe, where rates up
to 0.05 kg a.i./ha will usually suffice. Viewed overall, the available
data show no marked differences in residue levels between the U.S. and
western Europe for equivalent use rates and intervals. If the view is
taken that the MRL should encompass all residue data obtained from the
recommended use rates, then values as high as 17 mg/kg need to be
noted. The U.S. has established an MRL of 20 mg/kg. However, the
highest levels were recorded from untrimmed lettuce heads and in only
two other trials out of 38 in the U.S. did residues exceed 10 mg/kg.
The Meeting agreed that in estimating a maximum residue level a small
percentage of the data could be rejected, particularly if such data
represented the most severe use patterns, including a programme of 15
applications and a one-day preharvest interval.
Data presented to the 1979 Meeting showed that permethrin
residues in lettuce are present mainly in the wrapper leaves rather
than the hearts. In the U.S., the lower values tended to be achieved
where some degree of field trimming had taken place and the higher
ones where it had not.
A similar pattern was seen in more recent U.K. trials, in which
residue levels in wrapper leaves were generally higher than in hearts.
This was most marked in a variety in which the outer leaves were very
broad and open and therefore received a higher spray deposit. However,
the exposed nature of the leaves also leads to more rapid losses by
photochemical degradation and/or wash-off by weathering, with the
result that a more rapid decline in whole lettuce residues was
observed.
The area/weight ratio of large and small lettuce heads appeared
to influence the distribution of residues more than any difference
between EC formulations. Residues on the hearts of small lettuce were
significantly higher than those on larger samples.
Examination of the individual lettuce heads making up one sample
lot showed that the maximum residue on individual whole lettuce may be
up to 50% higher than the mean value. The type of lettuce did not
appear to influence this variability.
The Meeting proposed a reduction of the estimated maximum residue
level from 20 mg/kg to 10 mg/kg. It was recognized that residues
resulting from the severe use patterns needed to be confirmed under
commercial growing conditions and the Meeting proposed selective
surveys for this purpose (see FAO/WHO 1980a, 2.10 "Need for selective
residue surveys").
Residue data from trials on almonds, asparagus, horseradish,
olives and sunflower seed enabled the Meeting to estimate maximum
residue levels of permethrin for these commodities. Data from Canada
indicated that under Canadian use patterns residues on grapes would
exceed the current CCPR proposal of 1 mg/kg and a revised maximum
residue level was estimated.
The residue data on leeks examined at the 1979 JMPR were reviewed
and, without the prospect of a group MRL for bulb vegetables, the
Meeting proposed a level for leeks based exclusively on the available
data. Data from Finland confirmed the estimates of maximum residue
levels for cucumber, rapeseed and tomato, but indicated that residues
on currants could exceed the limit under discussion in CCPR.
Data on the fate of permethrin during processing and cooking
confirmed the general stability of permethrin residues.
RECOMMENDATIONS
The Meeting recommended that the levels listed below are suitable
for establishing (temporary) maximum residue limits. The levels refer
to the sum of cis and trans isomers of permethrin.
Commodity MRL (mg/kg)
Almonds 0.1
Asparagus 1
Grapes 2 (1)
Horseradish 0.5
Leeks 0.5 (5)
Lettuce 10(20)
Olives 1
Sunflower seed 1
Sunflower seed oil (crude and refined) 1
FURTHER WORK OR INFORMATION
Desirable
Selective surveys of residues in lettuce known to have been
treated under practical growing conditions with use patterns which
include up to 15 applications and a one-day preharvest interval.
Sampling and sample preparation should follow the recommendations of
CCPR (IUPAC) (see 1982 JMPR Report, para 2.4),
REFERENCES
Burke, S. and Hulm, Y. Permethrin residues in olives. ICI Plant
1979 Protection Division data. (Unpublished)
Fitzpatrick, R.D. Permethrin residues on asparagus. ICI Americas Inc.
1982a Agricultural Chemicals Division Report No. TMU0840/B.
(Unpublished)
1982b Permethrin and permethrin metabolite residues on sunflower
seed and stover. ICI Americas Inc. Agricultural Chemicals
Division Report No. TMU0880/B. (Unpublished)
Fujie, G.H. Determination of FMC 33297 residues in/on lettuce. FMC
1976 Corporation Agricultural Chemical Group Report No. W-0122.
(Unpublished)
Fujie, G.H. Determination of FMC 33297 residues on lettuce. FMC
1979 Corporation Agricultural Chemical Group Report No. W-0239.
(Unpublished)
Pearson, F.J. Permethrin and permethrin metabolite residues in
1982 almonds. ICI Americas Inc. Agricultural Chemicals Division
Report No. TMU0901/B. (Unpublished)
Swaine, H. and Rippington, D. Permethrin residues in apples and
1982 tomatoes: effect of cooking on residues. ICI Plant
Protection Division Residue Data Report No. PP557B044.
(Unpublished)
Swaine, H. and Sapiets, A. Permethrin residues in crop samples
1979a analysed during 1977-78: Leaf, root and forage crops. ICI
Plant Protection Division Report No. RJ0081A. (Unpublished)
Swaine, H. and Sapiets, A. Permethrin residues in crop samples
1979b analysed during 1977-78: Garden and household products. ICI
Plant Protection Division Report No. RJ0082A. (Unpublished)
Swaine, H., Froggatt, D.A., Burke, S. and Robbins, A.J. Permethrin
1980a residues in lettuce, U.K., 1980. ICI Plant Protection
Division Residue Data Report No. 404/PP557-B032.
(Unpublished)
Swaine, H., Froggatt, D., French, D.A., Farrelly, E. and Robbins, A.
1980b Permethrin residues in lettuce, UK, 1980. ICI Plant
Protection Division Residue Data Report No-402/PP557B031.
(Unpublished)
Swaine, H., Sapiets, A. and Robertson, S. Permethrin residues in
1980c lettuce, UK, 1979. ICI Plant Protection Division Residues
Data Report No. 357/PP557B026. (Unpublished)
Swaine, H., Sapiets, A. and Robertson, S. Permethrin residues in
1981 lettuce under glass, Denmark, 1980. ICI Plant Protection
Division Residues Data Report No. PP557B0040. (Unpublished)
Ussary, J.P. Permethrin residues in lettuce. Ten ICI Americas Inc.
1975-77 Agricultural Chemicals Division Reports. (Unpublished)
1978 Permethrin residues on lettuce. ICI Americas Inc.
Agricultural Chemicals Division Report No. TMU0404/B.
(Unpublished)
1980a Permethrin residues on almonds. ICI Americas Inc.
Agricultural Chemicals Division Report No. TMU0482/B.
(Unpublished)
1980b Permethrin residues in asparagus. ICI Americas Inc.
Agricultural Chemicals Division Report No. TMU0478/B.
(Unpublished)
1980c Permethrin residues in untrimmed lettuce. ICI Americas Inc.
Agricultural Chemicals Division Report No. TMU0510/B.
(Unpublished)
1981a Permethrin residues in almonds after aerial applications.
ICI Americas Inc. Agricultural Chemicals Division Report No.
TMU0571/B. (Unpublished)
1981b Permethrin and permethrin metabolite residues on horseradish
roots. ICI Americas Inc. Agricultural Chemicals Division
Report No. TMU0687/B. (Unpublished)
1982 Permethrin and permethrin metabolite residues in sunflower
seed processing fractions. ICI Americas Inc. Agricultural
Chemicals Division Report No.TMU0897/B. (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: 1983 evaluations)
Permethrin (Pesticide residues in food: 1984 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)