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    PESTICIDE RESIDUES IN FOOD - 1984


    Sponsored jointly by FAO and WHO






    EVALUATIONS 1984




    The monographs



    Data and recommendations of the joint meeting
    of the FAO Panel of Experts on Pesticide Residues
    in Food and the Environment and the
    WHO Expert Group on Pesticide Residues
    Rome, 24 September - 3 October 1984

    Food and Agriculture Organization of the United Nations
    Rome 1985

    ACEPHATE

    Explanation

         Acephate was first reviewed by the 1976 JMPR 1/, at which time
    residue limits were recommended on a variety of commodities.
    Additional MRLs or revisions were made in 1979 and 1981 on the basis
    of additional information. Toxicological aspects were also examined
    again in 1982.

         On several occasions the CCPR has requested the JMPR to consider
    acephate and methamidophos MRLs and the relation between them, most
    recently at its 16th Session.

         Since 1976 the JMPR has estimated separate limits for acephate
    and methamidophos to accommodate the use of either as a pesticide.
    Since 1979 the JMPR has sought to estimate additional methamidophos
    limits, or revise existing ones, to accommodate methamidophos residues
    resulting from the use of acephate. There are currently methamidophos
    limits for all crops in the Codex system for which there are acephate
    limits, as well as methamidophos limits for some crops on which
    apparently only methamidophos is used. In some cases the methamidophos
    limits are intended to accommodate only acephate uses. Although
    residue data and good agricultural practice information have never
    been sufficient to define fully the relation between acephate and
    methamidophos uses, the existing limits are intended to accommodate
    GAP as far as possible. This evaluation considers additional
    information which has been provided (see also methamidophos elsewhere 
    in these evaluations).

    RESIDUES IN FOOD AND THEIR EVALUATION

    USE PATTERN

         Additional good agricultural practice information which was
    provided is shown in Table 1.

        Table 1.  Use patterns of methamidophos
                                                                           

                                         Application      Interval between
    Country and crop       Formulation   rate             last application
                                         (kg a.i./ha)     and harvest, days
                                                                           

    Canada
      All uses are
      non-food uses.

    New Zealand 2/

      Brassica vegetables  75% WP        0.75-1.0                  7
      Citrus               "             75 g a.i./100 1          14
      Potatoes             "             0.75                      7
      Lettuce              "             0.75                      3
      Tamarillos           "             75 g a.i./100 1          14
      Tobacco              "             0.75                      -
      Tomatoes             "             0.75                      3
                                                                           

    1/  See Annex 2 for FAO and WHO documentation
    2/  Replaces 1976 submission
    
    RESIDUES RESULTING FROM SUPERVISED TRIALS

         Residues resulting from New Zealand field trials are summarized
    in Table 2 (New Zealand, 1984).

    Apples, pears, avocados, boysenberries.  The limited residue data
    (without good agricultural practice information) provided to this
    meeting are insufficient to support a limit.

    Cabbage.  On several occasions the JMPR has been requested to
    consider lowering the 5 mg/kg MRL. Substantial residue data were
    provided to the 1981 JMPR to supplement data reviewed earlier, but
    without information on GAP. The 1981 meeting concluded that there was
    no basis for lowering the limits. Information on GAP and limited new
    residue data were provided to the present meeting from New Zealand.
    The single value at the approved 7-day pre-harvest interval was 0.8
    mg/kg acephate, but this gives no reasons to lower the MRL, especially
    in view of the 1981 JMPR data from the U.S.A. (with no approved use on
    cabbage) which indicate that residues approaching 5 mg/kg at 7 days
    can result from application rates similar to the rate considered good
    agricultural practice in New Zealand. Even with the outer wrapper
    leaves removed, the U.S. data would require a 2 mg/kg limit at 7 days.
    Additional residue data and information on GAP are needed, including
    GAP for those European countries which have already provided some
    residue data.

    Lettuce.  The 5 mg/kg limit estimated by the 1979 JMPR is more than
    adequate to accommodate the residue of 2.1 mg/kg found at 3 days
    (reflecting good agricultural practice in New Zealand) reported to
    this meeting. The meeting noted that the CCPR had retained the
    original 1976 JMPR estimate of 10 mg/kg.

    Citrus fruit.  New Zealand data reviewed by the 1976 JMPR, with data
    on one additional sample (Table 2), were re-evaluated in the light of
    current GAP in that country. Maximum residues in the whole fruit
    (calculated from peel and pulp residues) of approximately
    3 mg/kg at the recommended 8-day interval support the current mg/kg
    limit.

    Potatoes.  Limited additional residue data, together with
    information on GAP (7-day pre-harvest interval) in New Zealand, do not
    require a change in the 0.5 mg/kg limit established by the 1981 JMPR
    for a 14-day pre-harvest interval. The original 1 mg/kg limit
    estimated by the 1976 JMPR was based on a 3-day interval.

    Tree tomatoes (tamarillos).  Data were available from four trials
    with a maximum residue of 0.46 mg/kg at the recommended 14-day
    interval and application rates reflecting good agricultural practice
    in New Zealand.

    Tomatoes.  The maximum residue was 0.2 mg/kg at the 3-day interval
    recommended in New Zealand. There is no basis for revising the current
    5 mg/kg limit.

    EVIDENCE OF RESIDUES IN FOOD IN COMMERCE OR AT CONSUMPTION

         Information was available on acephate residues in cucumbers,
    mushrooms and pears from the monitoring of domestic and imported
    samples in Sweden for the period January 1, 1981 to December 12, 1983
    (Table 3; Bergman, 1984). No limits have been estimated by the JMPR
    for these commodities.

    NATIONAL MAXIMUM RESIDUE LIMITS

         The following MRLs of New Zealand were reported to the meeting.

                                                 MRL, mg/kg

              Brassica vegetables                     2

              Citrus                                  5

              Tamarillos                              0.5

              Fruiting vegetables                     1

              Leafy vegetables                        6



        Table 2.  Residues of acephate and methamidophos resulting from supervised field trials with acephate in New Zealand.

                                                                                                                                      
                                        Application                                                    Residues, mg/kg
    Crop        Year                                                                                                                  
                                        rate
                            No.      kg a.i./ha                         Interval,   acephate            methamidophos    New Zealand
                                     (g a.i./100 1)    formulation      days                                             Report
                                                                                                                                      

    Apples      1971        5        2.5               75WP             13          0.63                0.04             PB 2041
                (report              (75)              registered
                date)

                                                                                    whole     flesh                      PB 7/3/5
                                                                                                                         April 1980

    Avocados    1970-80     6        0.125             "                0           1.8       0.68
                                     (50)                               7           1.5       0.56
                                                                        14          0.24      0.26                       PB 7/3/3
                                                                        28          0.09      0.11                       Feb. 1982

    Boysen       1980       2-5      1.5               "                0                     26.2                       PB 7/3/3
    berries                          (75)                               1                     26
                                                                        3                     26.5
                                                                                              20
                                                                        4                     19.6
                                                                        5                     15.9
                                                                        7                     22
                                                                                              14.6
                                                                        9                     18.2
                                                                        13                    8.7
                                                                        18                    4.6
                                                                        21                    2.5

                                                                                                                                      

    Table 2.  (continued)

                                                                                                                                      
                                        Application                                                    Residues, mg/kg
    Crop        Year                                                                                                                  
                                        rate
                            No.      kg a.i./ha                         Interval,   acephate            methamidophos    New Zealand
                                     (g a.i./100 1)    formulation      days                                             Report
                                                                                                                                      

    Cabbage     1972-73      3       0.84              75 WP            0           0.6                 0.13             PB/2041
                                                       registered       3           1.2                 0.24             June 1973
                                                                        7           0.8                 0.17             and
                                                                                                                         Feb. 1972
                            1        1.1               "                10          1.2                 0.2
                            3        0.84              "                16          <0.4                0.08
                                                                        23          <0.4                0.05

                1971        1        0.6-1.7           "                49-50       0.2                 0.04
                                                                                    0.16                0.06
                                                                                    0.12                <0.01

    Lettuce     1978        2        1                 75 WP            0           2.5                                  PB 2041
    (whole                           (116)             registered       1           6.6                                  May 1979
    head)                                                               3           2.1
                                                                        7           <0.1
                                                                        10          0.6
                                                                        14          0.2

    Oranges     1973        9        (75)              "                26          1.6                 0.16

    Pears       ?           6        5                 75 WP
                (report              (112)             registered       43          0.47                0.07             PB/24041
                1972                                                                                                     Feb. 1972

                                                                                                                                      

    Table 2.  (continued)

                                                                                                                                      
                                        Application                                                    Residues, mg/kg
    Crop        Year                                                                                                                  
                                        rate
                            No.      kg a.i./ha                         Interval,   acephate            methamidophos    New Zealand
                                     (g a.i./100 1)    formulation      days                                             Report
                                                                                                                                      

    Potatoes    1973        3-5      0.42-             "                4           <0.05               <0.05            PR/2041
                                     0.84                                                               June 1973
                                     (50-136)

    Tree        1982        8        (75)              "                0           0.47                0.005            PB 7/3/14
    tomatoes                                                            1           0.31                0.005            June 1983
    (Tamarillos )                                                       3           0.12                -
                                                                        8           0.16                0.003
                                                                        14          0.19                0.005
                                                                        21          0.15                0.005
                1981        7        4.2               "                0           0.82
                                     (75)                               1           0.94
                                                                        3           0.60
                                                                        7           0.39
                                                                        14          0.46
                                                                        20          0.40
                                                                        28          0.28

    Tamarillos 1982         10       3.75              75 WP            1           0.57                0.009
                                     (75)              registered       3           0.21                0.009            PB 7/3/2
                                                                        7           0.28                0.009            June 1983
                                                                        14          0.35                0.012
                                                                        22          0.18                0.005
                                                                        28          0.17                0.009
                1977        5        (50)              "                56          0.17                -                PB 7/3/14
                                                                                                                         Oct. 1977

                                                                                                                                      

    Table 2.  (continued)

                                                                                                                                      
                                        Application                                                    Residues, mg/kg
    Crop        Year                                                                                                                  
                                         rate
                            No.      kg a.i./ha                         Interval,   acephate            methamidophos    New Zealand
                                     (g a.i./100 1)    formulation      days                                             Report
                                                                                                                                      

    Tomatoes    1978        3-4      1                 "                0           0.33                -                PB/2041
                                     (66.7)                             1           0.61                -                May 1979
                                                                        3           0.19                -
                                                                        7           0.20, 0.93          -
                                                                        10          0.14                -
                                                                        16          0.13                -
                                                                                                                                      
    
    Table 3.  Domestic and import monitoring of acephate in selected 
              commodities (1981-1983)

                                                                  

                                        No. of samples
    Food        Origin       No. of     within given range (mg/kg)
                             samples    < 1.01     1.01 - 2.53
                                                                  

    Cucumber    Sweden       312        312
                Imported     416        411        5

    Mushroom    Sweden       28         28
                Imported     18         17         1

    Pear        Sweden       151        150
                Imported     515        515        1
                                                                  


    APPRAISAL

         The JMPR has on several occasions been requested to consider
    acephate and methamidophos together in the light of their
    relationship. There has never been sufficient information to do this
    and that is still the case. Separate limits have been estimated for
    the two compounds. Methamidophos limits have been proposed for all
    crops for which there are acephate limits and some methamidophos
    limits have been estimated to cover the use of methamidophos alone.

         In the case of animals, acephate limits of 0.1 mg/kg have
    previously been estimated for the meat and fat of cattle and pigs,
    milk, eggs and poultry on the basis of feeding trials with acephate
    plus methamidophos. No acephate limits have been estimated for sheep
    or goats, for which there are methamidophos limits.

         Some good agricultural practice information and supervised trials
    residue data were available to the present meeting from one country. 
    Data were insufficient to estimate limits for apples, avocados or
    boysenberries and there was no information on GAP for these
    commodities. Newly submitted information did not provide a basis for
    changes in the current limits for cabbage, lettuce, citrus fruit,
    potatoes or tomatoes. In the case of tree tomatoes (tamarillos), the
    data reflected good agricultural practice in one country and enabled
    the meeting to estimate a temporary limit.

         Limited domestic and import monitoring data for acephate were
    available on commodities for which limits have not been estimated.

    RECOMMENDATIONS

         The meeting examined residues data from supervised trials
    reflecting good agricultural practice on a number of crops. From these
    the meeting was able to confirm previously recommended TMRLs and
    estimate one new maximum residue level which is recommended as TMRL.
    The estimates reflect levels which may occur when acephate is used in
    practice and when the reported intervals between last application and
    harvest are observed. They refer only to the parent compound.

                                                                     

                                              Pre-harvest interval
    Commodity            TMRL (mg/kg)         on which recommendation
                                              is based
                                                                     

    Tree tomato                               0.514
    (Tamarillo)
                                                                     

    REFERENCES

    New Zealand    Information on good agricultural practice and
    1984           supervised residue trials provided by the New Zealand
                   government.

    Bergman, I.,   Information on residues in food in commerce provided by
    1984           the Swedish Contact Point, International Secretariat,
                   The National Food Administration, May 14, 1984.
    


    See Also:
       Toxicological Abbreviations
       Acephate (ICSC)
       Acephate (Pesticide residues in food: 1976 evaluations)
       Acephate (Pesticide residues in food: 1979 evaluations)
       Acephate (Pesticide residues in food: 1981 evaluations)
       Acephate (Pesticide residues in food: 1982 evaluations)
       Acephate (Pesticide residues in food: 1984 evaluations)
       Acephate (Pesticide residues in food: 1987 evaluations Part II Toxicology)
       Acephate (Pesticide residues in food: 1988 evaluations Part II Toxicology)
       Acephate (Pesticide residues in food: 1990 evaluations Toxicology)
       Acephate (JMPR Evaluations 2002 Part II Toxicological)
       Acephate (JMPR Evaluations 2005 Part II Toxicological)