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    PESTICIDE RESIDUES IN FOOD - 1980


    Sponsored jointly by FAO and WHO






    EVALUATIONS 1980





    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, 6-15 October 1980




    CAPTAN

    Explanation

    Captan has been reviewed by the Joint Meeting on several occasions,
    initially in 1965 and most recently in 1978 (FAO/WHO, 1966, 1979).
    Maximum limits have been recommended on numerous commodities on the
    basis of those reviews.

    In response to reservations of two delegations who questioned the need
    for a 40 mg/kg limit on cherries, the 8th Session of the Codex
    Committee on Pesticide Residues returned the proposal to Step 6 and
    requested governments to send data.  Data were provided and evaluated
    by the 1977 Joint Meeting (FAO/WHO, 1978) which retained the 40 mg/kg
    limit pending additional information on national use patterns and
    supervised trials.  A limited amount of data were provided to the 1978
    Joint Meeting (FAO/WHO, 1979) but they were insufficient to enable a
    revision the of 1969 recommendation to be made.

    The 1980 Meeting was provided with, and evaluated, additional
    information on good agricultural practice on apples and potatoes and
    residues of captan on cherries after spraying and on potatoes after
    post-harvest treatments.

    USE PATTERNS

    On apples in the Netherlands

    A formulation containing 55.37 captan and 16.77 nitrothal-isopropyl
    has been used since 1979 to control apple scab and mildew.  The
    interval between last application and harvest is 21 days.

                                                           
    Treatment             Application         Rates
                            g/100l            kg/ha
                                                           

    Weekly spray          110 with            1.65 with
    from the beginning    34g                 0.5kg
    of blossoming         nitrothal-          nitrothal-
    until June            isopropyl           isopropyl

    Mid-June until        82.5 with           1.24 with
    mid-August,           25.5g               0.38kg
    spraying at           nitrothal-          nitrothal-
    10-12 day intervals   isopropyl           isopropyl
                                                           

    On Potatoes in the USA

    In the USA captan is used pre-harvest on potatoes at a rate of 5.6
    kg/ha ai, with no limitation between last application and harvest, and
    at a rate of 0.12% ai as a spray or dip post-harvest.

    RESIDUES IN FOOD

    RESIDUES RESULTING FROM SUPERVISED TRIALS

    Residue data resulting from pre- and post-harvest uses of captan on
    cherries and post-harvest uses on potatoes are summarized in Tables 1
    and 2 (Stauffer, 1979; Canada, 1979).  The post-harvest treatment data
    are the first such data made available.

    Although most of the pre-harvest trials on cherries do not reflect the
    maximum 0.24% rates permitted by good agricultural practice (FAO/WHO,
    1978) they do indicate that residues at 0 day (or even 7-8 days) after
    last application can be expected to be at least 20 mg/kg.  In fact,
    the highest residues resulted from rates of one fourth to one half the
    maximum permitted rates.  These data therefore are consistent with
    earlier pre-harvest data on cherries examined by the Joint Meeting.

    The 40 mg/kg limit for captan on cherries previously recommended by
    the Joint Meeting was based on pre-harvest uses only.  Residues
    resulting from post-harvest application approximating good
    agricultural practices were 18.4 mg/kg or less in 44 of 45 samples and
    44.8 mg/kg for the remaining sample (Stauffer, 1979).  The ranges are
    given in Table 3.

    NATIONAL MAXIMUM RESIDUES LIMITS

    The Netherlands reported the following MRLs to the meeting.

    Apricots                    20 mg/kg

    Other fruit and vegetables  15 mg/kg

    Wheat                       0.1 mg/kg



        TABLE 1. Summary of residues of captan on cherries from pre- and post-harvest applications

                                                                                                                                             

    Country       Cultivar/       Year           Application                       Residues1 (mg/kg) at intervals (days) after application
    (reference)   type                    no.     kg ai/ha      formulation     0       1           3-5      7-8      10-12     14-15     17
                                               (spray concen.)
                                                                                                                                             
    Pre-harvest

    Canada        Stella          1979     3     1.65 (0.3%)        5OW              0.08-1.5
    (1979)                                                                          (0.670.51)

                  Bing                     7     3.4 (0.1%)                          0.6-5.7
                                                                                    (3.82.2)

                  Golden                   8     3.4 (0.1%)                          2.9-5.5
                                                                                    (4.21.1)

    U.S.A.        Bing            1963     1     0.09%              5OW        4.3-6                                           4.6-5.5    4.5
    (Stauffer,
    1979)         sweet           1975     5     3.4 (0.12%)                    0.6

                  sour                                                          2.6

                  Bing            1976     2     5.6 (0.24%)                            7.9

                  Montmorency              6     2.2 (0.08%)                    13     20           15       5.9      4.3
                                                                                21.3   11           18.7    20                   8.2

                  Montmorency              6     1.68 (0.06%)                   12.3   14.3          8.3     5.5      1.9
                                                                                20     16.3          9.7    15.5                12.3
                  Emperor Francis
                  & Napoleon      1977     7     2.2 (0.06%)                            4.3                  0.92

                  Montmorency              7     3.4 (0.12%)                                                          8.2
                                                                                                                      7.4

    TABLE 1.  Continued...

    Country       Cultivar/       Year           Application                       Residues1 (mg/kg) at intervals (days) after application
    (reference)   type                    no.     kg ai/ha      formulation     0       1           3-5      7-8      10-12     14-15     17
                                               (spray concen.)
                                                                                                                                             
                  Montmorency     1978     5     1.1 (0.12%)        80W         16.1   15            9.9     7.4      7.1        2
                                                                                17.1    5.3         11.2     8.3

    Post-harvest

    U.S.A.        Bing            1963           0.09%              5OW          4.6
    (Stauffer,                                                                   3.6
    1979)
                  Bing                     1     0.14%              80W        1.6-4.7
                                                                              (2.71.2)

                  Black                                                          4.9

                  Tatarian                                                       3.9

                  Chapman         1964     1     0.05%                           0.4
                                                 0.19%                         4.5-11.6
                                                                               (9.52.9)

                  Bing                                                             2

                  Lambert         1965           0.12%              50W                             0.86     0.94

                  Chapman         1967                                          2.9-3.7
                                                                               (3.30.35)

                  un-named                                                       3.4
                                                                                 3.4

                  Bing                           0.12%           flowable        7.2
                                                                                 8.7

    TABLE 1.  Continued...

    Country       Cultivar/       Year           Application                       Residues1 (mg/kg) at intervals (days) after application
    (reference)   type                    no.     kg ai/ha      formulation     0       1           3-5      7-8      10-12     14-15     17
                                               (spray concen.)
                                                                                                                                             
    U.S.A.        un-named        1967     1     0.12%              50W         <0.05-4
                                                                               (0.91.1)

                                  1968     1                        80W         18.4
                                                                                16
                                                 0.12%           flowable       14.8
                                                                                13.5
                                                                                                                                             

    1 Mean and standard deviation in brackets.


    TABLE 2.  Summary of Residues of Captan on Potatoes from Post-harvest treatments in USA

                                                                                                        
    State          Year             Applications                     Residue (mg/kg)
                           no.    % concentration     formulation    after dipping
                                     ai in dip
                                                                                                        

    Washington     1954     1           0.12            50W               9.0
                                                                         13.2 (3.4 after washing)
                                                                          3.7 (0.8; 0.8 after scrubbing)
                   1954     1           0.12            50W               8.6
                                                                         12.3
                                                                          6.9
                                                                          7.8
                   1955     1           0.24            50W               4.3
                                                                          3.7
                   1955     1           0.12            50W               3.0
                                                                          4.0
                            1           0.24            50W               9.3
                                                                          7.8
                            1           0.12            50W               5.5
                                                                          5.2

    California     1955     1           0.12            50W               7.1
                                                                          8.0
                                                                          4.4
                                                                          5.0
                                                                          5.6
                                                                          6.0
                                        0.24            50W               6.3
                                                                          7.0
                                                                          9.5
                                                                          9.8

    TABLE 2.  Continued...

    State          Year             Applications                     Residue (mg/kg)
                           no.    % concentration     formulation    after dipping
                                     ai in dip
                                                                                                        

    North          1955     1           0.12            50W               3.5
    Carolina                                                              4.3
                                                                          4.9
                                                                          4.8
                                                                          3.2
                                                                          4.0
                                                                          3.3
                                                                          3.3

    Idaho          1955     1           0.12            50W               3.4
                                                                          3.4
                                                                          3.3
                                                                          3.7
                                        0.24            50W               5.7
                                                                          6.5
                                                                         10.5
                                                                         10.0

    New York       1955     1           0.12            50W               2.5
                                                                          2.0
                                                                          2.6
                                                                          1.9
                                                                          2.5
                                                                          2.1
                                                                          2.2
                                                                          2.2
                                                                          3.0
                                                                          3.2
                                                                          4.2
                                                                          4.0

    TABLE 2.  Continued...

    State          Year             Applications                     Residue (mg/kg)
                           no.    % concentration     formulation    after dipping
                                     ai in dip
                                                                                                        
    Oregon         1955                 0.12            50W               3.5
                                                                          3.4
                                                                          4.2
                                                                          4.8
                                        0.24            50W               4.0
                                                                          4.1
                                                                          7.0
                                                                          6.9
                                                                                                        

    Stauffer, 1980
    

    TABLE 3.  Captan residues on cherries from post-harvest uses (at day
    of application)

                                            
    Range         Number            Percent
    (mg/kg)       in range          in range
                                            
    40-45          1                  2.2
    20-39.9        0                  0.0
    15-19.9        2                  4.4
    10-14.9        5                 11.1
    5-9.9          3                  6.7
    0.05-4.9      34                 75.6
    Total         45                100.0
                                            

    EVALUATION

    APPRAISAL

    The meeting was provided with additional information on good
    agricultural practice and further residue data for captan on cherries
    and potatoes.

    In the case of cherries, the Joint Meeting had previously recommended
    a 40 mg/kg limit for captan on the basis of residue data resulting
    from pre-harvest applications.  Subsequent review of additional
    residue data resulting from pre-harvest uses did not support a
    proposed reduction of that limit.  The additional pre-harvest data,
    and for the first time, residue data from post-harvest applications
    are reviewed in this addendum and considered in conjunction with data
    previously evaluated.

    The newly submitted pre-harvest data, resulting mostly from
    application rates of less than the maximum permitted by good
    agricultural practice, are consistent with the earlier findings.  At
    the maximum application rates permitted by good agricultural practice,
    previous evaluations had shown that residues may be up to 53 mg/kg at
    0 day or 25-29 mg/kg at 7-9 days after last application.  On the basis
    of pre-harvest data alone therefore, there is no justification for a
    limit lower than the 40 mg/kg limit previously recommended.  The
    recently submitted post-harvest data show that residues on cherries,
    like those from pre-harvest uses, can exceed 40 mg/kg.

    In the case of potatoes, residues can approach 15 mg/kg from
    post-harvest uses alone.  Good agricultural practises in some
    countries allow higher rates and shorter intervals for pre-harvest
    treatments than previously considered although no data were available
    for those uses.

    On the basis of the new data the Meeting found it necessary and was
    able to estimate new maximum residue levels for cherries and potatoes
    to cover pre- and post-harvest uses on cherries and post-harvest uses
    on potatoes.

    RECOMMENDATIONS OF RESIDUES LIMITS

    The meeting concluded that the levels listed below were suitable for
    establishing maximum residue limits to replace the existing figures.

                                                                

    Commodity           Estimated Maximum Residue Levels (mg/kg)
                                                                

    Cherries                            50

    Potatoes                            20
                                                                

    FURTHER WORK OR INFORMATION

    Desirable

    Additional information on national use patterns and corresponding
    residue data from supervised trials, in particular from pre-harvest
    uses on potatoes.


    REFERENCES

    Canada. (1979) Studies conducted by Agriculture Canada Central
    Experimental Farm, Ottawa Canada, KIA 0C5 and made available by Peter
    R. Bennett, Division of Additives and Pesticides, Food Directorate,
    Health Protection Branch, Health and Welfare Canada, Ottawa, Canada,
    K1A 0L2.

    Stauffer. (1979) Unpublished reports submitted by Stauffer Chemical
    Company, 1200 South 47th Street, Richard, California 94804.
    Pre-harvest studies are identified as FSDS No. A-14005, A-17638,
    A-17635, A-13626, A-13627, A-17616, A-13621, A-13622, A-19931,
    A-17615, and A-12730 and Ag. Tox. Report 409. Post-harvest studies are
    in Ag. Tor. Reports 409, 411, 419, 421, 502, 503, 760, 993, 1002,
    1035, 1233, and 1234 Agricultural Toxicology, University of
    California, Davis.

    Stauffer. (1980) Unpublished reports submitted from the California
    Spray-Chemical Corporation, dated October 5 and October 14, 1955 from
    James M. Cripps and entitled 'Captan-potatoes'.
    


    See Also:
       Toxicological Abbreviations
       Captan (HSG 50, 1990)
       Captan (ICSC)
       Captan (PIM 098)
       Captan (FAO/PL:1969/M/17/1)
       Captan (WHO Pesticide Residues Series 3)
       Captan (WHO Pesticide Residues Series 4)
       Captan (Pesticide residues in food: 1977 evaluations)
       Captan (Pesticide residues in food: 1978 evaluations)
       Captan (Pesticide residues in food: 1982 evaluations)
       Captan (Pesticide residues in food: 1984 evaluations)
       Captan (Pesticide residues in food: 1984 evaluations)
       Captan (Pesticide residues in food: 1990 evaluations Toxicology)
       Captan (Pesticide residues in food: 1995 evaluations Part II Toxicological & Environmental)
       Captan (IARC Summary & Evaluation, Volume 30, 1983)