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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

    ETHOPROPHOS

    IDENTITY

    Chemical Name

    O-ethyl S,S-dipropyl phosphorodithioate (IUPAC and CAS)

    Synonyms:  ethoprop (common name adopted by the American National
    Standards Institute); Mocap (R); Prophos (R); VC 9-104

    Structural Formula

                    O  S - CH2 - CH2 - CH3
                    " /
    CH3 - CH2 - O - P
                      \
                       S - CH2 - CH2 - CH3

    Other information on identity and properties

    Molecular weight         242.3

    Description              clear pale yellow liquid

    Density                  d20 1.094
                              4

    Boiling point            86 - 91C/0.2 mm Hg

    Vapour pressure          46.5 mPa at 26C

    Solubility               750 mg/l water; 50% wt/wt in acetone,
                             1,2-dichloroethane, diethyl ether, ethanol,
                             acetate, petroleum spirit and xylene.

    Partition coefficient    140
    octanol/water

    Hydrolysis               Rapidly hydrolysed at 25C and pH 9

    Thermal stability        Stable 8 hours at 150C, 12 weeks; at 50C

    Chemical stability       In acid media: stable up to 100C. In alkalin
                             media: moderate hydrolysis at 25C, rapid at
                             100C.

    Purity of the technical  > 94%*
    material                 *n-propyl isomer 93.7%
                             isopropyl isomer 0.3%/
                             satisfactory information on the other
                             impurities was provided by the manufacturer.

    Formulations             Granular 5, 10 and 20%
                             EC about 60, 200, 500 and 700 g/l

    RESIDUES IN FOOD AND THEIR EVALUATION

    USE PATTERN

         Ethoprophos is a non-systemic, non-fumigant nematicide, which is
    also effective against several soil-borne insects. It is applied to
    several annual and perennial crops, in general at sowing or planting.
    Owing to its contact and non-fumigant action it has to be worked into
    the soil immediately after application and to be brought to the soil
    level where the pest population in the following crop will mainly
    occur, i.e. in the root zone.

         The dosage range is 3 - 10 kg a.i./ha, depending on soil type,
    crop, pest organism and soil management (see Table 1).

         Because of the absence of systemic action the residues in the
    aerial parts of crops at harvest are, with very few exceptions very
    low, of the order of 0.02 mg/kg or less.

    RESIDUES RESULTING FROM SUPERVISED TRIALS

         Residue data were supplied from a large number of trials in which
    soil applications were carried out to control pests in several main
    crops planted or sown immediately after the application. Data were
    from several countries in Europe, America and some other regions. The
    data are summarized in Table 2.

    General comment on data

         The residues in crops whose edible parts grow in the top soil
    layer are in general low except in the case of carrots. However,
    interferences are found and levels may exceed 0.092 mg/kg, depending
    on how thoroughly adhering soil particles are removed by washing or
    otherwise removing soil particles from the samples.

    Fruit Crops

    Grapes.  Grapes grown in soils treated with ethoprophos dosages up
    to 30 kg a.i./ha did not show measurable residues (<0.02 mg/kg) even
    when relatively short pre-harvest intervals for this crop (80 days)
    were observed.

    In normal growing practice the period between application and harvest
    will be longer than 80 days.

    Bananas, treated at planting or both at planting and during
    development with dosages of about 10 kg a.i./ha or 2  7 g a.i./plant
    stool, did not show residues in fruits harvested 8-170 days after the
    last application.

        Table 1.  Recommended uses and dosage rates
              Application at sowing or planting, if not otherwise stated.

                                                                                             

    Type and group                       Crop                       Dosage rate,
                                                                    kg a.i./ha
                                                                                             

    Fruit:
      Citrus fruits                      citrus sp.                 10
      Berries and other small fruits     Grapes                     6-10
                                         Strawberries               5-10

      Tropical fruit,inedible peel       Bananas                    10 (2x6 g per stool)
                                         Pineapple                  10-15

    Vegetables:
      Bulb vegetables                    Onions                     8-10
      Brassica vegetables                Cabbage                    4-10
      Fruiting vegetables,cucurbits      Cucumbers                  3-10
                                         Gherkins                   6-10
                                         Melons(cantaloupes)        8-10

      Fruiting vegetables, other
      than cucurbits                     Eggplant                   8-10
                                         Peppers                    6
                                         Tomatoes                   8-10

      Leafy vegetables                   Lettuce                    4

      Legume vegetables                  Common bean 1              8-10
                                         Lima bean                  8-10
                                         Soybean                    6-10
                                         Garden pea, field
                                         pea                        6-10

      Root vegetables                    Carrots                    4
                                         Potatoes                   4-10
                                         Radish                     4-6
                                         Sweet potato               6-10
                                         Sugar beet                 8
                                         Turnip                     6-10

      Stem and stalk vegetables          Sugarcane                  4-10

      Cereal grains                      Maize                      6-10
                                         Other cereal grains        3 2

      Oil seeds                          Peanuts                    6-10

      Miscellaneous crops                Tobacco                    8
                                                                                             

    1  Synonyms: French bean, string bean, snap bean.
    2  Dosage against wireworms.
    

        Table 2.  Ethopropos residues resulting from supervised trials

                                                                                                                                              

                                                      Application             Number                     Residues, mg/kg
                                                                              of                         (ethoprophos only)
                                                  rate,                       trials        P H I        average and
    Crop              Country        Year      kg a.i./ha       formulation   (replicates)  (days)       (range)                    Ref.
                                                                                                                                              

    Fruits

    Grapes            France         1970      15               10 G           1            80           <0.01                      CNRA
                                               30               10 G           1            80           <0.01

    Strawberries      Netherlands    1979      10               10 G           2(8)         310-327      <0.01                      Duphar
                                               10               10 G           1(4)         362           0.01 (<0.01-0.02)
                                     1981      10               10 G           2(6)         82-159       <0.01                      Duphar
    (glass-house)                    1980      20               10 G           1(3)         198           0.1 (0.07-0.13)           Duphar
    Bananas           Costa          1969      5-13 g/pl        10 G           3            8-77         <0.02                      Mobil
                      Rica                     1x
                                     1969      3-6.5 g/pl       10 G           4            10-111       <0.02                      Mobil
                                               1-2x
                                     1969      3-6.5 g/pl       10 G           6            8-170        <0.02                      Mobil
                                               1-2x
                                     1969      3-7 g/pl         10 G           2            60-120       <0.02                      Mobil
                                               2x

                      Ivory          1968/69   7.6-10 g/pl      10 G           5            119          <0.02                      Mobil
                      Coast                    2x

    Pineapple         Hawaii         1966/68   1                10 G           2            565-619      <0.02
    fruit of                                   2                10 G           3            532-619      <0.02
    plant crop                                 4                10 G           3            532-619      <0.02
                                               8                10 G           1            565          <0.02
    fruit of                                   1                10 G           1            930          <0.02
    ratoon crop                                2                10 G           1            930          <0.02
                                               4                10 G           1            930          <0.02
                                               8                10 G           1            930          <0.02
                                                                                                                                              

    Table 2.  (continued)

                                                                                                                                              
                                                      Application             Number                     Residues, mg/kg
                                                                              of                         (ethoprophos only)
                                                  rate,                       trials        P H I        average and
    Crop              Country        Year      kg a.i./ha       formulation   (replicates)  (days)       (range)                    Ref.
                                                                                                                                              

    The tops and leaves of the plant crop and ratoon crop at all dosages after the above PHIs showed residues of less than 0.02 mg/kg
    (at our about limit of determination)

    Fruit tops        Ivory          1968      4.5              10 G           5            360          <0.02                      Mobil
    Tops              Coast                    4.5              10 G           5            360          <0.02                      Mobil

    Vegetables
    Bulb vegetables   France         1977      6                10 G           2                         <0.005                     INRA
    Onions                                     10               10 G           1                         <0.005                     INRA

                      USA            1976      3.4              10 G           1(4)         108           0.0009                    Hunt,
                                               6.7              10 G           1(4)         108           0.035                     1981
                                               13.4             10 G           1(4)         108           0.068

                      USA            1976      3                10 G           1(4)         42            0.120.03 (0.07-0.19)     Argauer,
                                               6                10 G           1(4)         42            0.520.13 (0.32-0.89)     1978
                                               12               10 G           1(4)         42            1.340.13 (1.09-1.64)

    Brassicas         USA            1976      3.4              10 G           1(4)         56           <0.01                      Argauer,
    Cabbage                                    6.7              10 G           1(4)         56           <0.01                      1978
                                               13.4             10 G           1(4)         56           <0.01

    Fruiting,
    vegetables,
    cucurbits
    Cucumber          Netherlands    1978      7.5              10 G           2(8)         31-37        <0.01                      Duphar
    (glass-house)                              10               10 G           2(8)         31-37        <0.01
                                               15               10 G           2(8)         31-37        <0.01
                                     1978      7.5              10 G           3(12)        47           <0.01
                                               10               10 G           3(12)        47           <0.01
                                               15               10 G           3(12)        47           <0.01
                                                                                                                                              

    Table 2.  (continued)

                                                                                                                                              

                                                      Application             Number                     Residues, mg/kg
                                                                              of                         (ethoprophos only)
                                                  rate,                       trials        P H I        average and
    Crop              Country        Year      kg a.i./ha       formulation   (replicates)  (days)       (range)                    Ref.
                                                                                                                                              

                      France         1982                       10 G                        0            <0.05                      Rhne-Poulenc
                                                                                            7            <0.05
                                                                                            22-28        <0.05

    (outdoor)         USA            1976      3.4              10 G           1(4)         58-62        <0.05                      Hunt,
                                               6.7              10 G           1(4)         58-62        <0.05                      1982
                                               13.4             10 G           1(4)         58-62        <0.05

    Gherkin           Netherlands    1978      15               10 G           3(12)        42-45        <0.01                      Duphar

    Melon             France         1977      10               10 G           2                         <0.005                     INRA

    Melon             USA            1976      3.4              10 G           1 (4)        98           <0.01                      Argauer,
    (cantaloupes)                              6.7              10 G           1(4)         98           <0.01                      1978
                                               13.4             10 G           1(4)         98           <0.01

    Fruiting
    vegetables, non
    cucurbits

    Eggplant          USA            1976      3.4              10 G           1(4)         77            0.0270.004 (0014-0.034)  Argauer,
                                               6.7              10 G           1(4)         77            0.0440.007 (0.036-0.05)  1978
                                               13.4             10 G           1(4)         77            0.0860.011 (0.061-0.116)

    Pepper            USA            1977      2.2              10 G           1                         <0.01
                                               4.5              10 G           1                         <0.01
                                               6.7              10 G           1(2)                      <0.01
                                               13.4             10 G           1                         <0.01
                                               20.1             10 G           1                         <0.01
                                                                                                                                              

    Table 2.  (continued)

                                                                                                                                              

                                                      Application             Number                     Residues, mg/kg
                                                                              of                         (ethoprophos only)
                                                  rate,                       trials        P H I        average and
    Crop              Country        Year      kg a.i./ha       formulation   (replicates)  (days)       (range)                    Ref.
                                                                                                                                              

    Tomato            France         1970      15               10 G           1(2)         127          <0.001                     INRA
                                     1977      10               10 G           1(2)                      <0.005                     INRA

    (glass-house)     Netherlands    1978      15               10 G           1(3)         48           <0.01)                     Duphar
                                     1979      501              20 G           3(2-4)       113-129      <0.01                      Duphar

    (outdoor)         USA            1976      3.4              10 G           1(4)         80-86        <0.005                     Hunt,
                                               6.7              10 G           1(4)         80-86        <0.005                     1981
                                               13.4             10 G           1(4)         80-86        <0.005

                      USA            1976      3.4              10 G           1(4)         91           <0.01                      Argauer,
                                               6.7              10 G           1(4)         91           <0.01                      1978
                                               13.4             10 G           1(4)         91           <0.01

    Leafy
    vegetables

    Lettuce           USA            1976      3.4              10 G           1(4)         87           <0.005                     Hunt,
                                               6.7              10 G           1(4)                      <0.005                     1981
                                               13.4             10 G           1(4)                      <0.005

                      USA            1976      3.4              10 G           1(3)         56            0.02 (<0.01-0.05)         Argauer,
                                                                                                                                    1978
                                               6.7              10 G           1(4)                       0.04 (0.02-0.08)
                                               13.4             10 G           1(3)                       0.1 (0.03-0.23)
    roots of                                   13.4             10 G           1(3)         56           max.  0.14
    lettuce

                                                                                                                                              

    Table 2.  (continued)

                                                                                                                                              

                                                      Application             Number                     Residues, mg/kg
                                                                              of                         (ethoprophos only)
                                                  rate,                       trials        P H I        average and
    Crop              Country        Year      kg a.i./ha       formulation   (replicates)  (days)       (range)                    Ref.
                                                                                                                                              

    Lettuce           Netherlands    1979      30               10 G           1(3)         310          <0.01                      Duphar
    (rotational                      1979/80   30               10 G           1            327          <0.01
    crop after
    Gherkins)

    Legume
    vegetables

    Common bean       USA            1977      3.4              10 G           1(4)                       0.02                      Narain,
    (string b.)                                6.7              10 G                                      0.03                      1980
                                               13.4             10 G                                      0.07

                      USA            1978      3.4              10 G           1(4)                       0.01
                                               6.7              10 G                                      0.09
                                               13.4             10 G                                      0.11

    (snap b.)         USA            1976      3.4              10 G           1(4)         66-77        <0.005                     Hunt,
                                               6.7                                          66-77        <0.005-0.008               1981
                                               13.4                                         66-77         0.005-0.018

    (French b.)       France         1977      6                10 G           2                         <0.005                     INRA

    Lima bean         USA            1977      3.4              10 G           1(4)                       0.02                      Narain,
                                               6.7              10 G           1(4)                       0.13                      1980
                                               13.4             10 G           1(4)                       0.02

                      USA            1978      3.4              10 G           1(4)                       3.34                      Narain,
                                               6.7              10 G           1(4)                       4.16                      1980
                                               13.4             10 G           1(4)                       3.38
                                                                                                                                              

    Table 2.  (continued)

                                                                                                                                              

                                                      Application             Number                     Residues, mg/kg
                                                                              of                         (ethoprophos only)
                                                  rate,                       trials        P H I        average and
    Crop              Country        Year      kg a.i./ha       formulation   (replicates)  (days)       (range)                    Ref.
                                                                                                                                              

    Soybean           USA            1966      2.2              10 G           3(4)         158-165      <0.02                      Mobil
                                               4.5              10 G
                                               6.7              10 G

                                     1966      2                10 G           2(1+2)       171-172      <0.02                      Mobil
                                               2.6
                                               3.3

                                     1968      1.7              10 G           1(2)         186          <0.02                      Mobil

                                     1979      6                EC 60/l        1(2)         81           <0.02                      Mobil

                                     1979      3                EC 60g/l       1(2)         175          <0.02                      Mobil
                                               6                EC 60 g/l

    Soybean hay                      1979      3                EC 60g/l       1(2)         175          <0.02                      Mobil
                                               6                EC 60g/l

    Pea               USA            1976      3.4              10 G           1(4)         56           <0.01                      Argauer,
                                               6.7              10 G           1(4)                                                 1978
                                               13.4             10 G           1(4)

                                     1977      3.4              10 G           1(4)         -             0.01                      Narain,
                                               6.7              10 G           1(4)                       0.01                      1980
                                               13.4             10 G           1(4)                       0.02

                                     1978      3.4              10 G           1(4)         -             1.65                      Narain,
                                               6.7              10 G           1(4)                       2.12                      1980
                                               13.4             10 G           1(4)                       1.06

                                                                                                                                              

    Table 2.  (continued)

                                                                                                                                              

                                                      Application             Number                     Residues, mg/kg
                                                                              of                         (ethoprophos only)
                                                  rate,                       trials        P H I        average and
    Crop              Country        Year      kg a.i./ha       formulation   (replicates)  (days)       (range)                    Ref.
                                                                                                                                              

    Root
    vegetables
    Carrot            France         1976      4                10 G           1                          0.105                     INRA
                                               6                10 G           1                          0.255

                      USA            1976      3.4              10 G           1(4)         84            0.140.035 (0.08-0.23     Argauer,
                                               6.7              10 G           1(4)         84            0.340.14 (0.15-0.74)     1978
                                               13.4             10 G           1(4)         84            0.810.186(0.28-1.14)

                                     1977      3.4              10 G           1(4)                       0.06                      Narain,
                                               6.7              10 G           1(4)                       0.78                      1980
                                               13.4             10 G           1(4)                       0.52

    Garden beet       USA            1976      3.4              10 G           1(4)         84           <0.01                      Argauer,
                                               6.7              10 G           1(4)         84           <0.01                      1978
                                               13.4             10 G           1(4)         84           <0.01

    Potato            France         1975      6 (broodcast)    10 G                        147          <0.01                      INRA
                                               2 (plant-hole)   10 G                        147          <0.01

                      France         1982      1                10 G           2            118-147      <0.02                      Rhne-
                                               3                10 G           2            118-147      <0.02                      Poulenc
                                               6                10 G           2            118-147      <0.02

                                     1982      0.4 (plant-hole) 10 G           2            157-170      <0.05                      Rhne-
                                                                                                                                    Poulenc

                      Fed. Rep.      1979      10               20 G           1(2-4)       58            0.1                       Schering
                      Germany                                                               87            0.07
                                                                                            134           0.02
                                                                                                                                              

    Table 2.  (continued)

                                                                                                                                              

                                                      Application             Number                     Residues, mg/kg
                                                                              of                         (ethoprophos only)
                                                  rate,                       trials        P H I        average and
    Crop              Country        Year      kg a.i./ha       formulation   (replicates)  (days)       (range)                    Ref.
                                                                                                                                              

                                     1979      10               20 G           1(2-4)       98            0.04                      Schering
                                                                                            118           0.06
                                                                                            139           0.02
                                     1979      10               20 G           1(2)         82           <0.01                      Schering
                                                                                            118          <0.01
                                     1979      10               20 G           1(2)         61            0.06                      Schering
                                                                                            75            0.03

                      Netherlands    1975      10               10 G           4(12)        132-153       0.01                      CIVO
                                     1980      10               20 G           1(4)         170          <0.003 (<0.002-0.006)      KvW A'dam
                                     1980      10               20 G           1(4)         160          <0.006 (<0.002-0.012)
                                     1980      10               20 G           1(4)         148          <0.004 (<0.002-0.008)

                      Jersey         1980      11               10 G           2(6)         64-65         0.021 (0.015-0.031)       Murphy

    peel              U.K.           1980      10               10 G           4(12)        128-129       0.018 (0.08-0.031)        Murphy
    flesh                                                                                                 0.0013 (<0. 001-0.005)

    Potato            U.K.           1971      11               10 G           1(2)         131           0.021 (0.02-0.022)        Fisons,
                                               11               10 G           2(3)         92            0.022 (0.018-0.027)       Chester-
                                               11               10 G           2(3)         120           0.025 (0.020-0.029)       ford Park
                                               11               10 G           2(3)         157           0.004 (0.004-0.005)
                                               11               10 G           2            80            0.032 (0.023-0.042)
                                               11               10 G           2            113           0.014 (0.007-0.022)
                                               11               10 G           2            136           0.005 (0.004-0.006)

                                                                                                                                              

    Table 2.  (continued)

                                                                                                                                              

                                                      Application             Number                     Residues, mg/kg
                                                                              of                         (ethoprophos only)
                                                  rate,                       trials        P H I        average and
    Crop              Country        Year      kg a.i./ha       formulation   (replicates)  (days)       (range)                    Ref.
                                                                                                                                              

                      USA            1969/     2.2 broodcast    10 G           1            161          <0.02                      Mobil
                                     1971      4.5 "            10 G           2            164          <0.02
                                     1973      6.6 "            10 G           1(5)         120-164      <0.02
                                               9   "            10 G en        1(8)         108-133      <0.02
                                                                EC 60 g/l
                                               3.4 row tr       10 G           2(6)                      <0.02
                                               4.5              10 G           1(3)                      <0.02
                                               3.4 row post     10 G           1(4)         86           <0.02
                                               4.4l emergence   10 G           1(3)         94           <0.02

    Sweet             USA            1966/     2.2              10 G           1(4)         124          <0.02                      Mobil
    potato                           1968      3.4              10 G           2(5)         124-156      <0.02
                                               4.5              10 G           2(5)         124-156      <0.02
                                               6.7              10 G           2(10)        127-153      <0.02
                                     1968      2.8              10 G           1            150          <0.02
                                     1967      4.5              10 G           1(2)         116          <0.02
                                               9                10 G           1(2)         116          <0.02
                                               13.4             10 G           1            116          <0.02

    Radish            USA            1976      3.4              10 G           1(4)         59            0.038                     Hunt,
                                                                                            66            0.018                     1981
                                               6.7              10 G           1(4)         59            0.079
                                                                                            66            0.031
                                               13.4             10 G           1(4)         59            0.345
                                                                                            66            0.163
                                               3.4              10 G           1(4)         42            0.120.023(0.008-0.18)    Argauer,
                                               6.7              10 G           1(4)         42            0.330.039(0.26-0.44)     1978
                                               13.4             10 G           1(4)         42            0.660.023(0.60-0.71)
                                                                                                                                              

    Table 2.  (continued)

                                                                                                                                              

                                                      Application             Number                     Residues, mg/kg
                                                                              of                         (ethoprophos only)
                                                  rate,                       trials        P H I        average and
    Crop              Country        Year      kg a.i./ha       formulation   (replicates)  (days)       (range)                    Ref.
                                                                                                                                              

                      USA            1977      3.4              10 G           1(4)                       0.01                      Narain,
                                               6.7              10 G           1(4)                       0.07                      1980
                                               13.4             10 G           1(4)                       0.03
                                     1978      3.4              10 G           1(4)                       0.09
                                               6.7              10 G           1(4)                       0.14
                                               13.4             10 G           1(4)                       0.09
                                     1977      6                10 G           2(2)                      <0.005                     INRA
                                               8                10 G           2(2)                      <0.005

    Turnip            USA            1976      3.4              10 G           1(4)         87            0.017                     Hunt,
    roots                                      3.4              10 G                        97            0.010                     1981
                                               6.7              10 G           1(4)         87            0.019
                                               6.7              10 G                        97            0.012
                                               13.4             10 G           1(4)         87            0.035
                                               13.4             10 G                        97            0.013

    leaves                           1976      3.4              10 G           1 (4)        87            0.018                     Hunt,
                                               3.4              10 G                        97           <0.005                     1981
                                               6.7              10 G                        87            0.041
                                               6.7              10 G                        97           <0.005
                                               6.7              10 G                        87            0.281
                                               6.7              10 G                        97            0.036

    roots             USA            1977      3.4              10 G           1(4)                       0.01                      Narain
                                               6.7              10 G                                      0.01                      1980
                                               13.4             10 G                                      0.02
                                     1978      3.4              10 G           1(4)                       0.15
                                               6.7              10 G                                      0.05
                                               13.4             10 G                                      0.06
                                                                                                                                              

    Table 2.  (continued)

                                                                                                                                              

                                                      Application             Number                     Residues, mg/kg
                                                                              of                         (ethoprophos only)
                                                  rate,                       trials        P H I        average and
    Crop              Country        Year      kg a.i./ha       formulation   (replicates)  (days)       (range)                    Ref.
                                                                                                                                              

    tops              USA            1977      3.4              10 G           1(4)                       0.01                      Narain,
                                               6.7              10 G           1(4)                       0.02                      1980
                                               13.4             10 G           1(4)                       0.13
                                     1978      3.4              10 G           1(4)                       0.05
                                               6.7              10 G           1(4)                       0.05
                                               13.4             10 G           1(4)                       0.05

    Stems and
    stalk
    vegetables

    Sugarcane         USA            1966/67   4.2              10 G           1            320          <0.02                      Mobil
    stalks                                     8.4              10 G           1            320          <0.02
                                               16.8             10 G           1            320          <0.02
    stalks            USA            1967/68   4.5              10 G           1(2)         315          <0.02
    leaves                                     4.5              10 G           1(2)         315          <0.02
    stalks            USA            1968/69   4.5              10 G           1(4)         366          <0.02
    leaves            USA            1968      5.6              19 G           1(6)         246          <0.92
    stalks                                     5.6              10 G           1(6)         246          <0.02
    leaves            USA            1966/67   6.7              10 G           1(4)         360          <0.02
    stalks            USA            1967/68   11.2             10 G           1(3)         350          <0.02
    leaves                                     11.2             10 G           1(3)         350          <0.02

    Cereal
    grain

    Maize             France         1982      3 (              EC 480         1 (4)        195          <0.05 (<0.05-<0.05)        Rhne-
                                               4 (pre-emergence g/l            1 (4)        195          <0.05 (<0.05-<0.05)        Poulenc
                                               6 (spraying                     1 (4)        195          <0.05 (<0.05-<0.05)
                                                                                                                                              

    Table 2.  (continued)

                                                                                                                                              

                                                      Application             Number                     Residues, mg/kg
                                                                              of                         (ethoprophos only)
                                                  rate,                       trials        P H I        average and
    Crop              Country        Year      kg a.i./ha       formulation   (replicates)  (days)       (range)                    Ref.
                                                                                                                                              

    ears              USA            1966      1.1              10 G           2(7)         160-165      <0.025                     Mobil
                                               2.2                             1(6)         165          <0.025

    ears + husk                                1.1              10 G           1(8)         155          <0.025
                                               2.2                             1(8)         155          <0.025

    Silage                                     1.1              10 G           3(15)        80-114       <0.025
                                               2.2                             2(14)        108-114      <0.025

    Oilseeds

    Peanut            USA            1968      2.2              10 G           2(5)         118-154      <0.02                      Mobil
                                               3.4              10 G           4(13)        138-166      <0.02
                                               4.5              10 G           3(12)        138-166      <0.02
                                               5.6              10 G           3(12)        138-166      <0.02
                                     1966      4.5              EC             1(3)         154          <0.02
                                               8.8              EC             1(2)         154          <0.02
                                               13.4             EC             1(2)         154          <0.02
                                     1973      2.2              10 G           1            143          <0.02
                                               3.4              10 G           1            164          <0.02
                                               6.7              10 G           1            164          <0.02
                                               8.8              10 G           1            143          <0.02

    Peanut hay                       1973      3.4              10 G           1            164          <0.02
                                               4.5              10 G           1            143          <0.02
                                               6.7              10 G           2(2)         143-164      <0.02
                                               8.8              10 G           1            143          <0.02
                                                                                                                                              

    Table 2.  (continued)

                                                                                                                                              

                                                      Application             Number                     Residues, mg/kg
                                                                              of                         (ethoprophos only)
                                                  rate,                       trials        P H I        average and
    Crop              Country        Year      kg a.i./ha       formulation   (replicates)  (days)       (range)                    Ref.
                                                                                                                                              

    Tobacco           France         1982      5                10 G           1(2-3)       110           0.07 (0.05-0.08)          Rhne-
    (green)                                    10               10 G           1(2-3)       110           0.16 (0.14-0.19)          Poulenc
                                               20               10 G           1(2-3)       110           0.38 (0.17-0.53)
                                     1982      5  (pre-         EC 480 g/l     1(2-3)       110           0.17 (0.16-0.20)          Rhne
                                               10 (emergence    EC 480 g/l     1(2-3)       110           0.27 (0.26-0.29)          Poulenc
                                               20 (spraying     EC 480 g/l     1(2-3)       110           1.01 (0.68-1.48)

    (green)           USA            1966      4.5              10 G           1(2)                      <0.02                      Mobil
                                               5.6              10 G           1(2)                      <0.02
                                               8.4              10 G           5(14)                     <0.02
                                               9.0              10 G           2(14)                     <0.02

    (cured)           USA            1965      5.7              10 G           5(7)         2             0.08(<0.02-0.15)          Mobil
                                     1970      6.7              EC             2(6)         2             0.02(<0.02-0.025)
                                     1967      11               EC             1            82           <0.02                      Mobil
                                                                                            102           0.036
                                                                                            116           0.024
                                               22               EC             1            82            0.1
                                                                                            102          <0.02
                                                                                            116          <0.02
                                                                                                                                              

    1) excessive dosage
    2)  composite leaf samples during growing season
    

    Pineapple.  Soil treatments shortly before or at planting did not
    result in residues in fruit of the planted crop (pre-harvest interval
    565-619 days) or of the ratoon crops (<0.02 mg/kg). In the latter
    crops the period between application and harvest was more than 900
    days. Residues in the tops and leaves of both the planted and the
    ratoon crops did not exceed 0.02 mg/kg (at or about the limit of
    determination).

    Vegetables

    Onions.  In some of the supervised trials with normal application
    rates (6-10 kg a.i./ha) residues above 0.02 mg/kg were found (for
    example Hunt et al 1981, Argauer and Feldmesser, 1978). Owing to the
    parchment structure and the development of successive coat layers soil
    particles are easily entrapped. It has to be recognised that complete
    removal of these soil particles is difficult.

    Beans, peas.  Residues are in general below 0.02 mg/kg on crops
    grown in soil treated at normal dosages shortly before or at planting.
    Residues exceeded 0.02 mg/kg only in very few cases (Narain, 1980) but
    these results can be explained as being due to soil particles with
    attached ethoprophos residues, since adhering soil particles were not
    removed.

    Fruiting vegetables

    Cucumbers, gherkins, melons (cantaloupes), tomatoes and cabbage.
    Residues at harvest on crops grown in ethoprophos-treated soil at
    normal dosages (6-10 kg a.i./ha) did not exceed 0.01 mg/kg. One series
    of supervised trials on eggplant showed residues above 0.02 mg/kg   
    (Argauer and Feldmesser, 1978). There was no apparent explanation for
    these results: the samples were washed before analysis to remove
    adhering soil.

    Lettuce.  In most supervised trials, residues at harvest did not
    exceed 0.02 mg/kg in lettuce grown on soil treated with dosages up to
    13 kg a.i./ha. Some results (Argauer and Feldmesser, 1978) showed
    higher residues. These may have been due to soil particles containing
    ethoprophos.

    Root vegetables

    Potatoes.  Extensive data were available from supervised trials on
    this crop from several countries in Europe and America. With very few
    exceptions residues at harvest were of the order of 0.02 mg/kg or
    less. Depending on the extent of washing or otherwise removing
    adhering soil particles from the samples some soil contamination was
    found, giving "residue" levels slightly above 0.02 mg/kg. In general,
    however, residues in samples which were thoroughly washed or brushed
    to remove adhering soil particles did not exceed 0.02 mg/kg.

    Carrots.  Residues at harvest were distinctly higher than in other
    crops in which the edible part grows in the top soil layer. Carrots
    grown in soil following soil application at normal dosages of 6-10 kg
    a.i./ha shortly before or at sowing showed residues at harvest of the
    order of 0.5-1 mg/kg. In view of these higher residues, the
    manufacturer does not recommend the use of ethoprophos for carrots.

    Radishes.  Residues in radishes at harvest were higher than
    0.02 mg/kg in several supervised trials. Entrapment of soil particles
    may have been partly responsible.

    Turnip roots.  Turnips grown in soil treated with normal dosages
    (6-10 kg a.i./ha) of ethoprophos showed varying residues. In some
    trials residues were 0.02 mg/kg or less, but in several others this
    level was exceeded. The highest level found was 0.15 mg/kg, but the
    turnip roots in this trial were not brushed or washed to remove
    adhering soil particles with ethoprophos residues.

    Sugarcane.  Sugarcane planted in soil treated at rates up to 15 kg
    a.i./ha (the recommended rate is 4-10 kg a.i./ha) did not show
    measurable residues at harvest. In an experiment in 1976 all the
    intermediate products in the sugar manufacturing process were
    analysed. No measurable amounts of ethoprophos (<0.02 mg/kg) were
    found in the mixed juice, clarified juice, syrups, raw sugar, molasses
    or bagasse. Ethoprophos in the mud could not be determined with the
    analytical method used.

    Maize

         Residues in maize treated immediately before or at sowing did not
    exceed 0.02 mg/kg.

    Peanuts

         Residues in peanuts and peanut hay were in general at or about
    the limit of determination of 0.02 mg/kg after soil application before
    or at planting.

         An extensive series of trials carried out in various regions in
    the USA also showed that the level of 0.02 mg/kg was in general not
    exceeded if ethoprophos was applied as a spray or drench at or shortly
    after pegging.

    Tobacco

         The residues in tobacco, and in composite samples from leaves
    taken at several sampling dates during the growing season were in
    general below 0.02 mg/kg.

         In an experiment to determine the carry-over in cigarette smoke,
    ethoprophos was added to cigarette tobacco. Only about 10% if the
    ethoprophos added appeared in the smoke stream. Since a cigarette is
    not entirely "consumed" but is in general smoked to a 30 mm butt, only
    about 60% of the tobacco is actually burned. The ethoprophos recovered
    from the smoke is about 14% of that applied to this amount of tobacco.
    The remainder is decomposed and/or volatilized or trapped by the
    unburned portion of the tobacco in the butt.

    FATE OF RESIDUES

    In animals

         Dogs were fed for three weeks (3  6 days/week) a diet containing
    0.025 0.25 and 2.5 ppm ethoprophos. The animals were sacrificed on the
    21st day and samples of muscle, kidney, liver and fat immediately 
    deep-frozen and analysed within a week. No residues (<0.01 mg/kg)
    were found in any of the tissues (Hazleton, 1968).

         Iqbal et al (1972) studied the metabolism of ethoprophos in
    rats and in liver microsomal systems. After oral administration by
    gavage of ethyl-14C-and dipropyl-14C-labelled ethoprophos to rats,
    chloroform-extractable radioactivity was recovered from urine of rats
    treated with the dipropyl-labelled compound. It contained traces of
    methyl propyl sulphide, methyl propyl sulphoxide and methyl propyl
    sulphone, all products of S-methylation and subsequent oxidation of
    the propylthiolate ion released from ethoprophos.

         The major water-soluble metabolite isolated from urine, liver
    microsomes and the liver supernatant fraction was O-ethyl S-propyl
    hydrogen phosphorothioate. The rat urine also contained ethyl
    dihydrogen phosphate ethyl dihydrogen phosphate, S-propyl dihydrogen
    phosphorothioate and S,S-dipropyl hydrogen phosphorodithioate. (See
    Tables 3 and 4).

         Rat and rabbit liver supernatant enzymes were able to
    O-de-ethylate ethoprophos in the presence of reduced glutathione.
    S-ethyl-14C-glutathione was produced when the supernatant preparations
    were incubated with ethyl-14C-ethoprophos, indicating that glutathione
    acted as an ethyl acceptor.

         In view of the metabolites identified in these studies the
    pathway of metabolic degradation of ethoprophos shown in Figure 1 can
    be proposed.

    FIGURE 1


        Table 3.  Urinary metabolites of S,S-dipropyl-14C-ethoprophos in the rat.

                                                                                                                  

                                                             % of administered radoactivity
                                                                                                                  
                                                      Male rats                        Female rats Compounds
                                                                                                                    
                                       0-6 hrs        6-12 hrs      12-24 hrs          0-8 hrs       8-24 hrs
                                                                                                                  

    Water fraction
    O-ethyl S-propyl
    hydrogen phosphorothate            23.06           5.29          5.79               20.79         22.32

    S-propyl di-hydrogen
    phosphorothioate                    7.55           3.15          2.64                3.65          5.88

    S,S-dipropyl
    hydrogen phosphorodithioate         1.40           1.01          0.97                1.12          0.83

    Sum of unknown A,J,K                6.01           2.15          1.00                1.85          0.56

    Chloroform extract                  0.10                                             0.10

    Methyl propyl sulphide              0.94           0.23                              0.18          0.10

    Methyl propyl sulphoxide                           0.46          0.40                              0.73

    Methyl propyl sulphone

    Total excreted                     38.39          12.29         10.77               27.60         30.42
                                                                                                                  

    Table 4.  Urinary metabolites of O-ethyl-14C-ethoprophos in the rat.

                                                                                                                  

                                                 Male rats                             Female rats
                                                                                                                  

    Compounds                        0-6 hr      6-12hr     12-24hrs        0-6 hrs      6-12hrs     12-24hrs
                                                                                                                  

    O-ethyl S-propyl
    hydrogen phosphorothioate        33.71        0.88       0.78            41.54        0.97        0.93

    ethyl dihydrogen
    phosphate                         3.49        0.24       0.12             4.26        0.49        0.21

    Sum of unknow A,E,J,K             9.80        0.18       0.07             7.16        0.23        0.05

    Chloroform fraction              <0.001                                  <0.001

    Total excreted                   47.09        1.30       0.96            52.95        1.58        1.19
                                                                                                                  
    
         The abbreviated Tables 3 and 4 indicate the quantitative
    distribution of the metabolites found in the urine extracts of rats
    (derived from Iqbal and Menzer, 1972).

    In plants

         Menzer et al (1971) studied the uptake and metabolism of
    ethoprophos in bean and maize plants grown on steam-sterilized soil
    treated with ethyl-14C-and dipropyl-14C-ethoprophos.

         Sterile soil was used to inhibit the biodegradation of the
    labelled ethoprophos and to reduce the adsorption capacity of the
    soil, so that the maximum amount of ethoprophos would be available for
    uptake by the plants. A number of organo-extractable and water-soluble
    metabolites formed by dealkylaton of ethoprophos and subsequent
    reaction, were detected. Some of these became incorporated into plant
    constituents. The proposed degradation pathway of ethoprophos in
    plants is shown in Figure 2.

         In the proposed metabolic scheme the role of propylthiolate ion
    is of critical importance. The S-propyl group has been found to be the
    favoured leaving group in a displacement reaction with hydroxide ion.
    The propylthiolate ion thus liberated is strongly nucleophilic and can
    react with a phosphorothioic ester in an analogous fashion to the
    reaction mechanism described by Harvey et al (1963).

    [(RO)2P(O)SR'+R'S  (RO)(R'S)P(O)O'+ R'SR]

    A similar reaction mechanism may be involved in the production of
    ethyl propyl sulphide in plants in which it was shown to be an
    important metabolite. It was present in significant quantities in
    methylene chloride extracts, although it was equivalent to only a very
    small percentage of the administered dose.

         Kirby and Warren (1967) indicated that the propylthiolate ion
    would itself be strongly thiphilic and would be expected to react
    further with another thiol thus forming a disulphide. Dipropyl
    disulphide was in fact isolated from the methylene chloride extracts
    of bean and maize plants grown on dipropyl-14C-ethoprophos-treated
    soil.

         The fact that O-ethyl S-propyl hydrogen phosphorothioate was the
    major component of the methanol-water fraction from maize plants may
    also indicate that the propylthiolate ion is formed as an important
    metabolic intermediate. In view of its importance and its role in
    de-ethylating ethoprophos it is of interest that desethyl-ethoprophos
    is not found in plants, although it is present in rat urine (Iqbal and
    Menzer, 1972; see Figure 1). Desethyl-ethoprophos was found however to
    be rather unstable and it probably loses propyl mercaptan to form
    S-propyl dihydrogen phosphorothioate which was found in plants.

    FIGURE 2

         The study of ethoprophos in plants has shown that the compound is
    rapidly converted to metabolites which are likely to be much less
    toxic than the parent compound. Its metabolism in plants is similar to
    that in animals, with only the slight differences with regard to the
    minor metabolite desethyl-ethoprophos mentioned above.

         Although ethoprophos is a phosphorodithioate pesticide, it
    differs from most of these compounds in not being a phosphorothionate
    and hence not needing oxydation to its oxygen analogue to make it an
    inhibitor of cholinesterase.

    In soil

         Soil samples spiked at 2 mg/kg and analysed after five months
    storage in a deep-freeze showed only a slight loss of ethoprophos
    (immediate recovery 95.2%; recovery after five months 82.3 and 84.5%).

         Soil samples were taken at regular intervals from field plots in
    the UK treated at normal dosages for potato cyst nematode control,
    11 kg/ha, and at the double rate of 22 kg/ha.

         One trial showed higher residues than the others: 22.9 mg/kg
    after 92 days and 17.5 mg/kg after 157 days. In other three trials,
    with treatment at 11 kg/ha residues declined to 4-10 mg/kg after
    100-150 days. From two of these trials an initial half-life between 10
    and 17 days could be calculated (see Table 5) (Fisons 1972).

         In another study on the dissipation of ethoprophos in soil,
    Norris and Garlick (1978) reported that the concentration of
    ethoprophos parent compound dropped to less than 10% of the initial
    concentration in about three to 20 weeks (half-life 5-35 days),
    depending on soil type and climatic conditions. Carbon dioxide was the
    predominant, if not the only, volatile metabolite or degradation
    product found in the headspace over the soils.

         Comparison of ethoprophos dissipation in various non-sterile
    soils suggests that soil micro-organisms may have a greater effect on
    the pesticide than soil characteristics, such as pH, organic matter
    content or texture (Norris and Garlick, 1978). Dissipation in soils
    with a high organic matter content is however much slower than in
    soils low in (low in organic, not low inorganic) organic matter (Smelt
    et al 1977, 1981; see below).

         Smelt et al (1977) in The Netherlands evaluated the rates of
    degradation and downward movement of ethoprophos under spring and
    summer field conditions in four soils in aluminium columns 40 cm long.
    A 10% granular formulation was incorporated in the top 10 cm at a rate
    of 10-10.5 kg a.i./ha. Under outdoor conditions in the periods
    mentioned the half-life was about 87 days in a humic sand and a peaty
    sand with pH values of 4.5 and 4.6 respectively. In a sandy loam and a
    loam soil with pH values of 7.2 and 7.3 respectively, the half-life
    ranged between 14 and 20 days. Under experimental conditions with


        Table 5.  Residues of ethoprophos in soil (air-dried before analysis)

                                                                                                                                              

                                                      Ethoprophos, mg/kg, in air-dried soil, after interval of (days)
                                                                                                                                              
    Dosage, kg a.i./ha      0        3        10        17      24       25       32       86       92       113      120      136      157
                                                                                                                                              

    22                      73.0     83.0     42.2      17.9             29.1              18.6              7.6               8.5
                            71.3     77.1     45.1      19.2             30.5              16.1              8.4               8.6

    11                      38.4              31 1      11.0                               4.4                                 5.2
                            40.7              30.7      10.0                               4.3                                 3.4

    11                                        37.7              24.5                                22.9                                17.5

    11                                        24.9              16.0              16.3                                8.1               9.7
                                                                                                                                              
    

    Table 6.  Calculated half-life of ethoprophos in three soils at 20C
              and 2C (Smelt et al 1981)

                                                                         

    Soil type             pH       Organic matter, %    Half-life (days)

                                                        20C      2C
                                                                         

    Silt loam           7.0-7.2          1.6            12        89
    Sandy loam          7.5-7.8          1.8            16        144
    Humic loamy sand    5.8-4.7          6.1            73        347 at
                                                                  6C 1
                                                                         

    1  The half-life of ethoprophos could not be estimated accurately at
       2C in this soil owing to the very low rate of decline.


    fallow soils and 35.3 cm rainfall, the downward movement of
    substantial amounts of ethoprophos by leaching and diffusion was
    restricted to a few cm.

         Smelt et al (1981) evaluated similarly the movement and
    conversion of ethoprophos in soil in winter in The Netherlands.
    Ethoprophos (10% granular) was mixed into the top 9 cm of soil columns
    40 cm long and 8.4 cm in diameter. The percolating water was collected
    and at regular intervals layers of the soil column were separated and
    analysed by GLC with a flame photometric detector in the phosphorus
    mode at 526 nm wavelength. In the winter there was a distinct movement
    in the two loamy soils, although ethoprophos was retained in the top
    30 cm. In a humic loamy sand soil the mobility was comparatively low
    and ethoprophos could not be measured in the percolating water. At the
    end of April in the year following ethoprophos application to the soil
    columns on October 25th, only about 10-20% of the applied dose was
    left in the two loamy soils, whereas about 75 percent still remained
    in the humic loamy sand soil.

         Substantial conversion of ethoprophos was found to occur in
    incubation studied in the laboratory in loamy soils (pH 7.5-7.8,
    7.0-7.2 and 4.7-5.0) at temperatures down to 2C. At 10C the
    conversion rate coefficients (kp) in silt loam, sandy loam and humic
    loamy sand were 0.023, 0.0187 and 0.0035 respectively, whereas at 2C
    the conversion coefficients were 0.0078, 0.0048 and about 0.0005
    respectively. The conversion of ethoprophos in the humic loamy sand
    almost stopped at the lowest temperature, but continued at 2C in the
    two other soils. The following half life times could be calculated for
    the three soil types.

    In processing

         Some data were available on the effects of processing, e.g. of
    winegrapes into must and wine, and on residues in products such as
    sugarcane and intermediate products during the manufacture of sugar
    and tobacco. Results are discussed in the section on supervised
    residue trials.

         No data were available on the effect of the household or
    industrial cooking of vegetables or fruit. Such data may not be
    important in the view of the low residues at harvest in most fruits
    and vegetables (at or below the limit of determination).

    METHODS OF RESIDUE ANALYSIS

         Several methods have been developed and made available, which
    have been modified and improved with time. Most of the samples from
    the supervised trials were analysed by GLC, using a flame photometric
    detector in the phosphorus mode. Several clean-up procedures have been
    proposed, using column chromatography or other physico-chemical
    separation techniques. For commodities with a high fat or vegetable
    oil content, additional clean-up steps may be needed. The limit of
    determination was 0.005-0.02 mg/kg, in some commodities 0.05 mg/kg. In
    some experiments, notably with tobacco, analysis by GLC with a
    sulphur-mode detector seemed to be more effective. The limit of
    determination was about 0.02 mg/kg.

         These methods, especially the GLC methods with flame photometric
    detection in the phosphorus mode operating at a wavelength of 536 nm,
    are suitable or can be adapted for regulatory purposes. The currently
    available multi-detection methods for organophosphorus compounds can
    also be used for the determination of ethoprophos.

    NATIONAL MAXIMUM RESIDUE LIMITS

         The following national MRLs, established or under consideration,
    were reported to the meeting.

                                                                                                  

    Country                       Commodity                        MRL, mg/kg
    (date of establishment
    of MRL)
                                                                                              

    Australia                     Bananas                          0.05
                                  Sugarcane                        0.1
                                  Tomatoes                         0.01

    Austria                       Potatoes (washed)                0.02

    Belgium(Feb. 1982)            Potatoes                         0.02
                                  Cereal grains                    0.02

    Brazil                        Vegetables                       No residue (at or
                                                                   about limit of
                                                                   determination)

    France                        Vegetables, except carrots       0.01
                                  Bananas                          0.01

    Fed. Rep. of Germany          Bananas, Pineapple,      )       0.02
                                  Fruiting vegetables,     )
                                  Soybeans, Potatoes.      )
                                  Sweet potatoes, Peanuts, )
                                  Maize                    )

    Italy (Feb. 1979)             Fruit and vegetables             0.02

    Luxembourg (June 1983)        Potatoes                         0.02

    Netherlands                   Strawberries                     0.01*
    (March 1984)                  Fruiting vegetables              0.01*
                                  Potatoes                         0.02
                                  Other food commoditie            0 (0.01*)

    USA                           Bananas                  )
                                  Pineapple fooder and     )
                                  forage                   )
                                  Cabbage                  )
                                  Cucumbers                )
                                  Fresh corn,including     )
                                  sweet corn (kernels      )
                                  + cob, husks removed     )
                                  Lima bean, Lima bean     )
                                  forage                   )
                                  Snap bean,snap bean      )
                                  forage                   )       0.02
                                  Soybean,soybean forage   )       (negligible
                                  Soybean hay              )        residue)

                                                                                              

    Country                       Commodity                        MRL, mg/kg
    (date of establishment
    of MRL)
                                                                                              

                                  Potatoes,sweet potatoes          )
                                  Maize (corn) grain,              )
                                  fodder and forage                )
                                  Sugarcane, Sugarcane             )
                                  fodder and forage                )
                                  Peanut, Peanut hay               )

    Yugoslavia                    All food commodities                                                                          
    0.02
                                                                                              

    * At or about limit of determination.
    

    APPRAISAL

         The meeting reviewed substantial information on the residue
    levels of ethoprophos from supervised trials on a variety of
    commodities in several countries in Europe, America and some other
    regions. Ethoprophos is an organophosphorus pesticide which is mainly
    used as a soil application at or shortly before planting or sowing
    against soil-borne nematodes and some soil-borne insects.

         The compound is formulated as 10% and 20% granules and as an EC.
    In contract to other organophosphorus or carbamoyl oxime nematicides,
    it has only a contact action with no systemic or fumigant effect. It
    has therefore to be worked into the top soil layer in which the pest
    organism mainly occurs, i.e. the root zone of the crop to be grown on
    the treated soil. Owing to the lack of systemic action the residues in
    the aerial parts of crops grown on treated soil are in general very
    low. Residues in the edible parts of crops which develop in the top
    soil layer may show higher and varying residues depending on how
    thoroughly soil particles with adhering ethoprophos residues are
    removed by washing, brushing or other cleaning procedures. In some
    crops soil particles are easily entrapped and complete removal is
    almost impossible.

         The meeting evaluated qualitative and quantitative aspects of the
    fate and metabolism of ethoprophos residues in plants and animals. The
    metabolic pathways in plants and animals are in principle similar, the
    only difference being a minor metabolite (desethyl-ethoprophos) found
    in the urine of rats but not in plants. The expected breakdown product
    of desethyl-ethoprophos is, however, found as a constituent of the
    plant residue.

         Information on analytical methods for ethoprophos and its
    metabolites was provided to the meeting. The current method of choice
    for residue analysis is GLC with a flame photometric detector operated
    in the phosphorus mode at a wavelength of 536 nm. The limit of
    determination is 0.005-0.02 mg/kg, depending on crop type, sample size
    and interferences not removed in the clean-up procedure. Additional
    clean-up steps may be needed for commodities with a high fat or
    vegetable oil content. The methods of residue analysis are suitable or
    can be adapted for regulatory purposes.

         Extensive information was made available on the current
    authorization or registration status of ethoprophos in various
    countries and the recommended good agricultural practice. Information
    was also made available on established national maximum residue
    limits.

    RECOMMENDATIONS

         The meeting examined residue data from supervised trials
    reflecting current good agricultural practices on a number of crops,
    but considered that the limited data available on egg plant, lima
    beans, common beans (i.e. French, snap or string beans) and radishes
    were not adequate to estimate maximum residue levels, especially since
    these data originated from only one country and the residue levels
    differed considerably from those in similar crops, without any
    apparent explanation. No maximum residue levels were estimated for
    tobacco since this commodity is not a food.

         From the extensive data available the meeting was able to
    estimate the maximum residue levels listed below. Since no ADI was
    allocated, these were recorded as guideline levels. They refer to
    ethoprophos only.


                                                                        

    Commodity                                             GL (mg/kg)
                                                                        

    fruit crops           grapes                          0.02*
                          strawberries                    0.02*
                          bananas                         0.02*
                          pineapple                       0.02*

    vegetables

    bulb vegetales        onions                          0.02*
    brassicas             cabbage                         0.02*
    fruiting
      vegetables          cucumbers                       0.02*
                          gherkins                        0.02*
                          melons                          0.02*

                                                                        

    Commodity                                             GL (mg/kg)
                                                                        

                          peppers                         0.02*
                          tomatoes                        002*
    leafy vegetables      lettuce                         0.02*
    legume vegetables     soybeans                        0.02*
                          peas                            0.02*

    root vegetables       beet root                       0.02*
                          potatoes                        0.02*
                          sweet potatoes                  0.02*
                          turnips                         0.02*

    stem and stalk
    vegetables            sugarcane                       0.02*

    cereal grains         maize                           0.02*

    oilseeds              peanuts                         0.02*

    misc.crops            pineapple fodder and forage     0.02*
                          soybean hay                     0.02*
                          sugarcane fodder and forage     0.02*
                          maize fodder and forage         0.02*
                          peanut hay                      0.02*
                                                                        

    * at or about the limit of determination


    REFERENCES

    Unpublished residue data provided by Industries, Governmental and non-
    Governmental Institutes made available by Rhone-Poulenc; reference
    codes Duphar, Fisons, Mobil, Rhone-Poulenc, INRA, CIVD, KUW.

    Argauer, R.J. and Feldmesser. J. Uptake of ethoprophos (Mocap) by ten
    1978      vegetables grown in soil treated for nematodes. J. Agr. Food
              Chem. 26 (1) 42-44.

    Harvey, G.R., Jacobson, H.I. and Jensen E.V. Phosphoric acid VI. The
    1963      reaction of trivalent phosphorus with organic disulphides.
              J. Amer. Chem. Soc. 85: 1618-1623.

    Hazleton. Mocap 21-day oral administration to dogs. Project No.
    1968      230/124. Report of Hazleton Laboratories, Fall Church,
              Virginia, to Mobil Chemical Co. (Unpublished).

    Smelt, J.H., Leistra, M. and Voerman, S. Movement and rate of
    1977      decomposition of ethoprophos in soil columns under field
              conditions. Pestic. Sci. 8 147-151.

    Smelt, J.H., Leistra, M., Dekker, A. and Schut, C.J. Movement and
    1981      conversion of ethoprophos in soil in winter: measured
              concentration patterns and conversion rates. Soil Science
              131 (4) 242-248.


    See Also:
       Toxicological Abbreviations
       Ethoprophos (ICSC)
       Ethoprophos (Pesticide residues in food: 1983 evaluations)
       Ethoprophos (Pesticide residues in food: 1987 evaluations Part II Toxicology)
       Ethoprophos (JMPR Evaluations 1999 Part II Toxicological)