IPCS INCHEM Home


    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

    CHEMICAL STRUCTURE 1

    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 165C. 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)