IPCS INCHEM Home


    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

    CAPTAN

    Explanation

         Captan was evaluated in 1965, 1969, 1973, 1974, 1977, 1978, 1980
    and 1982 1/ at which times numerous limits were estimated or revised.
    It was scheduled for toxicological evaluation in 1984 as a result of
    the 1982 review. The last residue review was in 1980 at which time
    limits for cherries and potatoes were revised and additional
    supervised trials data and information on good agricultural practice,
    especially on pre-harvest uses on potatoes, was considered desirable.

         Additional information on uses, monitoring data, residue trials,
    national tolerances and persistence is reviewed herein.

    RESIDUES IN FOOD AND THEIR EVALUATION

    USE PATTERN

         Information was available on nationally approved use patterns in
    four countries. Those of The Netherlands are summarized in Table 1 and
    those of New Zealand, Canada and Sweden in Table 2.

    RESIDUES RESULTING FROM SUPERVISED TRIALS

         Information on captan residues resulting from supervised trials
    was provided from three countries and the data are summarized in
    Tables 3-7. Pre-harvest intervals in one country were "nil" for all
    commodities, but longer in other countries. It is necessary therefore
    to consider residues shortly before harvest.

    Apples, pears.  Supervised trials residue data were provided by one
    of the countries (Canada) providing additional good agricultural
    practice information. In one trial (Table 3) application rates
    reflected good agricultural practice in that country, although none of
    the data reflected Canada's 7-day pre-harvest interval. Maximum
    residues were 3.2 mg/kg at 14 days after the last application and not
    markedly different at 21-22 days except for one residue of 8.4 mg/kg.
    Judging from the dissipation rate indicated, residues at the 7-day
    pre-harvest interval would probably not exceed 10 mg/kg. Data reviewed
    by the 1978 JMPR indicate that residues can approach or even exceed 10
    mg/kg from pre-harvest use alone.



              

    1/  See Annex 2 for FAO and WHO documentation.


        Table 1. National use pattern of captan in The Netherlands

                                                                                                                                 

    Crop and            Pest                Application rate    Formulation   Treatment                Pre-harvest     In use
    situation           controlled                                                                     interval        since
                                            g/100L   kg/ha                                             (days)

                                                                                                                                 

    Fruit:
    Apple and           Scab                120      2.5        wp 85%        spraying at 7-10         -               before
    pear                (Venturin sp.)                                        day intervals                            1965
                                                                              until mid-June

                                            100      2.0        wp 83%        spraying at 10-          -               before
                                                                              day intervals                            1965
                                                                              after mid-June
                                                                              until shortly
                                                                              before harvest

                        Scab + Fruit        120      2.5                      spraying at 7-12                         about
                        rot (Pexicula                                         day intervals                            1968
                        mulicortis                                            after mid-July
                                                                              until shortly
                                                                              before harvest

                        Nectrica-Fruit      200      2.0                      autumn spraying                          about
                        tree                                                                                           1968

    Cherry              Fruit-rot           120      2.5        wp 83%        spraying 14-8            4               1965
                                                                              days before
                                                                              harvest

    Strawberry          Fruit-rot           120      2.25       wp 83%        weekly sDraying          4               1965
    Outdoors            (Botrytis sp.)                                        from shortly before
                                                                              blossoming until
                                                                              4 days before harvest
                                                                                                                                 

    Table 1. (continued)

                                                                                                                                 

    Crop and            Pest                Application rate    Formulation   Treatment                Pre-harvest     In use
    situation           controlled                                                                     interval        since
                                            g/100L   kg/ha                                             (days)
                                                                                                                                 

    Strawberries        Fruit-rot                                             Not more than two        14              about
    glasshouse          (Botrytis sp.)                                        sprayings from                           1975
                                                                              blossoming until
                                                                              2 weeks before
                                                                              first harvest

    Blackberry          Botrytis sp.        120                 wp 83%        repeated                 4               before
    Raspberry                                                                 spraying                                 1965

    Currants            Botrytis sp.        120                 wp 83%        repeated                 10              before
    (black, red                                                               spraying                                 1965
    and white)

    Vegetables:         Anthracnose         120      1.2        wp 83%        repeated                 21              about
    Endive              (Marssonina sp.)                                      spraying until                           1968
                                                                              3 weeks before
                                                                              harvest

    Leek                Phytophtora         300      3.0        wp 83%        repeated spraying        21              about
                                                                              with 10-12 day                           1970
                                                                              intervals
                                                                                                                                 

    The wettable powder and a 10% dust are also used in floriculture and on nursery stock

    Table 2. National use patterns of captan in Canada, New Zealand and Sweden

                                                                                                             

                                                     Application rate              Interval, last
                                                     kg a.i./ha or                 application to harvest
    Commodity               Formulation              (kg a.i./10001)               (days)
                                                                                                             

                                                     CANADA

    Pre-harvest

    raspberry               solid, susp., WP         (1), multiple                        2
                            WP                       2.25 (with benomyl)

    blackberry              WP                       1.75, multiple
                            WP                       2.25 (with benomyl)

    loganberry              dust, WP                 1.1-1.75, multiple                   2

    blueberry               dust, WP                 1.75, multiple                       2

    strawberry              solid, WP                2.25-3.25                            2
                            dust                     2.5-4.25, multiple
                            WP                       3.25 (with benomyl)                  2

    rhubarb (in                                      1-1.5, multiple                      2
    forcing sheds)

    cucumber                solid, susp.             1.75-2.5 (young plants) or           2
                            WP, dust                 2.5-3.25 (mature plants);
                                                     multiple

    pepper                  5% dust                  Not given, multiple                  2

    eggplant                5% dust                  "     "       "                      2

    tomato (field,          solid, susp., WP         1-3, multiple                        2
    greenhouse              dust                     1.75-4.25                            2
                                                                                                             

    Table 2. (continued)

                                                                                                             

                                                     Application rate              Interval, last
                                                     kg a.i./ha or                 application to harvest
    Commodity               Formulation              (kg a.i./10001)               (days)
                                                                                                             

                                                     NEW ZEALAND
                                                     (Replaces 1973, 1975, 1977)

    Pre-harvest             80% WP                   2-4                                 "Nil"
                                                     or
    pip fruit                                        (0.1 - 0.15)

    stone fruit
    citrus
    grapes
    strawberries
    vegetables
    ornamentals

    Seed treatment          60%                      100-300 g a.i.
    Protectants             per 100 kg seed

    vegetables
    cereals
    fodder crops

                                                     SWEDEN

    Pre-harvest

    fruit orchards          formulation              0.05%                               21
                            unspecified
                                                                                                             

    Table 3. Captan residues on fruits resulting from supervised trials

                                                                                                                                           

                            Application                   Residues, mg/kg, at interval (days) after application
                                                     
    Crop                       rate                                                                                      
    Country         No.     kg a.i./ha   formulation      0       1      3     5       7-8    14    18      21-22  25-30   Reference
    Year                    (g ai/100L)
                                                                                                                                           

    Apple
    Canada
    1982            10      1 kg a.i.    50W                                                  2.1           0.7    0.6     Canadian Govt.
                            /1001 to                                                          2.9           0.9    1.7
                            run-off                                                           0.9           1.9    0.8
                                                                                              0.6           1.4    0.8
                                                                                              3.2           3.1    2.2
                                                                                              1.6           8.4    1.1
                                                                                              1.2           1.2    1.0
                                                                                              1.4           0.5    2.9

    Blueberry
    New Zealand
    1980            1       3.8          80WP             13      12.3   12            11.3   2.3           0.5    0.8     N.Z. Govt. Report
                                         (registered)                                                                      PB/7/3/3
                                                                                                                           May 1980

    1979            1       3            80WP             15      11.8   6.9           6.4    3             1.4
                            (100)

    1980            1       2            80WP             16.6    14.94  16.7          14.7   9             1.2    1.7
                            (100)                         13      12.9   12.           10.9   5.5           1      1.4

    1978            1       (120)        80WP                                                                      <0.05
                                                                                                                   0.03
    1979            2       (120)        80WP                     1.9    1.1   0.8     0.9    <0.05
                                                                  2.5    1.9   1       1      <0.05
                                                                                                                                           

    Table 3. (continued)

                                                                                                                                           

                            Application                   Residues, mg/kg, at interval (days) after application
                                                     
    Crop                       rate                                                                                      
    Country         No.     kg a.i./ha   formulation      0       1      3     5       7-8    14    18      21-22  25-30   Reference
    Year                    (g ai/100L)
                                                                                                                                           

    Currants
    New Zealand
    1979            4       1.3-2.9      80WP                                          4.43   3.3 2 4                      PB 7/3/3
                            (100-160)    registered                                    4.3    4.0 2
                            (2 trials)                                                        2.1 2
                                                                                              3.9 2

                    6       4.9-9        80WP                            17.84
                            (120)                                        19.1
                                                                         23.1
                                                                         20.3

                    6       1.6-2.5      80WP                            5.44
                                                                         6.2
                            (68-120)                                     5.2
                                                                         <0.05

                    1       2.2          80WP                     10     6.7           6.3    4.3
                            (120)                                                      5.4

                    1       8                                     5.8    3.9   3.6     0.6
                            (120)                                              1.35
                                                                                                                                           

    Table 3. (continued)
                                                                                                                                              

                      Application                 Residues, mg/kg, at interval (days) after application
                                               
    Crop                 rate                                                                                                  
    Country      no.   kg a.i./ha  formulation    0     1     2     5    7-8  14-15  17-20  21-22   25-30  31-35   68-75   >75     Ref.
    Year              (g ai/100L)
                                                                                                                                              

    Kiwi fruit
    New Zealand                                         
    1980         1      2.7        80WP                 <0.16            <0.1 <0.1                  <0.1                   0       N.Z. Govt.
                        (80)       registered                                                                                      report 13/5

                                                        
    1980         3      2.7        "                    7.16             1.9                        2.2                    0.2     "

    1979         2      1.4.1      80WP                                       2.7    1.2            1      1.1     <0.1    <0.1    N.Z. Govt.
                                                                                                    1      <0.6                    report
                                                                                                    1.2    <0.7                    PB 13/7/5
                                                                                                    <0.6   0.71
                                                                                                    <0.6
                                                                                                    <0.6
                                                                                                    <0.6
                                                                                                    <0.6
                                                                                                    2

    1979         1      1.1-4.4    80WP                                                                            Range 0.08-     "
                        3          (4 trials)                                                                            0.43
                                                                                                                   Mean 0.18
                                                                                                                   S.D. 0.13

    1978-79      9-14   1.5-3.5    80WP                 Range 6.3-                                                                 "
                        (100)                                15
    '                   (6 trials)                      Mean 9.2
                                                        S.D. 2.5
                                                        No. of samples:
                                                        17
                                                                                                                                              

    Table 3. (continued)

                                                                                                                                              

    Crop               Application              Residues, mg/kg, at interval (days) after application
                                                                                                                       
                          rate
    Country      no.   kg a.i./ha  formulation  0       1     2     5    7-8  14-15  17-20  21-22 25-30  31-35  90-120      Ref.
    Year               (g ai/100L)
                                                                                                                                              

    Kiwi fruit
    New Zealand                                                          Range 5.5-                                         N.Z. Govt.
    1978-79      9-10   1.5-3.2    80WP                                       13.8                                          Report
                        (100)      registered                            Mean 9                                            PB 4 June
                        (4 trials)                                       S.D. 2.5                                           1981
                                                                         No. of samples 17

                                                                                                           whole8
    1978-79      11-15  1.3-3.5    80WP         Range   4.2-7 1.7-  2.8- 2.1-   0.7-         2.2-   3.5-   0.9-
                        (100)                           14.3  10.5  6.5  13.1   9.2          12.5   10.7   5.5

                        (16 trials)             Mean    8.5  5.5  4.7 6.2   4.4         6.4   5.8   2.4

                                                S.D.    3     2.9   1.5  3.3    2.5          3.5    3.1    1.2

                                                No. of values 16   7     7    11     18           7      7      28

                                                                                                  edible 8,9

                                                                                            Range <0.1-0.4

                                                                                            Mean  0.04
                                                                                            S.D.  0.01
                                                                                     No. of values 24
                                                                                                                                              

    Table 3. (continued)

    1  Duplicate blueberry values represent different varieties
    2  12 days
    3  Each sample from each half of trial
    4  Each sample from each quarter of trial
    5  10 days
    6  Average of duplicates
    7  Range of means of individual trials at all intervals
    8  Samples at 90-120 days cool-stored
    9  All 90-120 day edible sample values <0.1 mg/kg except one each at 0.3 and 0.4 mg/kg
    
         This is confirmed in other Canadian trials (Table 7: Frank et
    al., 1984) where captan was applied to apples at the normal rate and
    half of it. Maximum residues varied from 15.7 mg/kg at day 0 to
    approximately 7 mg/kg at that country's 7-day pre-harvest interval or
    at 10 days. The authors note that at least 6 mg/kg is required for
    efficacy on apples and pears and suggest that a half-rate application
    near harvest may be adequate. Residues were reduced by rainfall in
    only two of the six trials and in some trials were relatively constant
    for 7 days. The number of applications did not appear to affect
    residue levels significantly. These authors also reported trials on
    pears in which residues were comparable to those in some apple trials
    (Table 7).

         These data and those reviewed by the 1977 and 1978 JMPRS indicate
    that residues may approach and occasionally exceed 10 mg/kg from 
    pre-harvest uses alone at intervals around 7 days and even
    occasionally approach 20 mg/kg at the 0-day interval permitted in some
    countries. Data reviewed by the 1977 JMPR indicate that post-harvest
    uses can also result in residues of the order of 10 mg/kg. There is no
    basis for lowering the current 25 mg/kg limit. This is supported by
    monitoring data (see "Residues in commerce or at consumption").

    Blueberries.  Supervised residue trial data were available from New
    Zealand (Table 3). Although it is not entirely clear what formulation
    was used, it was presumably the 80 WP since that is the product
    registered in that country for other fruit. No good agricultural
    practice information was provided. It is not clear on what basis the
    current 20 mg/kg Codex limit was estimated, although it is first
    recorded in the report of the 1973 JMPR. If the data presented to this
    meeting represent good agricultural practice, residues up to 17 mg/kg
    on the day of last application and 15 mg/kg even at 7-8 days show that
    the 20 mg/kg limit is required.

    Currants.  Residue trials data were available only from New Zealand
    (Table 3) and good agricultural practice information from The
    Netherlands. Good agricultural practice information was provided for
    "pip fruit" from New Zealand. Application rates on currants were
    consistent with those for pip fruit, although the approved withholding
    period was only identified as "nil". The interval is 10 days in The
    Netherlands, but these countries are not in close proximity, nor do
    they have similar climates. Maximum residues were 23, 6 and 4 mg/kg at
    3, 7-8, and 12 days respectively. Assuming the trials reflected good
    agricultural practice, as they apparently did, the current 20 mg/kg
    limit is supported.

    Kiwi fruit.  Residue data from 34 trials were provided from one
    country (Table 3). Application rates generally reflected approved
    rates in that country, although it is not clear how many applications
    are good agricultural practice, nor what the exact approved
    withholding interval is since it was only described as "nil". Numbers
    of applications ranged from one to 15. Data were available for
    intervals of one to 120 days from last treatment.

         The maximum residue 2 days after the last application was
    15 mg/kg. The highest mean residues in individual trials were
    14.3 mg/kg at 2 days and 10.7 mg/kg at 31-35 days. The maximum mean
    residue was 5.5 mg/kg even after 90-120 days after the last
    application when stored under "cool" conditions. Most residues in the
    edible portion of the 90-120 day samples were <0.1 mg/kg. The highest
    was 0.4 mg/kg.

         The number of applications appears to affect residue levels,
    which in some trials were relatively constant from 2 days to one month
    after application. Residues will, therefore, not necessarily decrease
    markedly even on relatively long storage.

         If the trials reflect good agricultural practice, a 20 mg/kg
    limit would appear to be required with a 2-day pre-harvest interval.
    Additional information on the approved number of applications and the
    exact withholding interval is need for the country in which the trials
    were conducted. Good agricultural practice information and residue
    data from additional countries are desirable.

    Cherries.  The persistence of captan on cherries has been
    investigated in relation to the reduction of one national tolerance to
    5 mg/kg (Northover et al., 1984). The concern was whether residues
    could be maintained at the 2-3 mg/kg level necessary for efficacy.
    Supervised trials reflecting commercial practice are summarized for
    sweet and sour cherries in Tables 4 and 5 respectively. Maximum
    residues were approximately 30 mg/kg on the day of last application
    and 2-4 mg/kg after 14 days in the 1983 trials, but were lower in the
    1982 trials with maxima of 13 and 5 mg/kg at 0 and 14 days
    respectively in sour cherries. Sweet cherry residues were generally
    somewhat higher than sour at comparable intervals. The author
    considered the 1983 data to be exceptionally high and suspected
    analytical difficulties, but there is no firm evidence to support that
    view.

         These and other data from the same studies indicate that rain can
    reduce residues by 50%, but show that losses can be much less. In the
    absence of rain, residues decreased little during 7 days. The authors
    also demonstrated that water washing can remove 50% of the residue or
    substantially more, depending on its thoroughness (see "Fate of
    residues in processing").

         These data together with those previously reviewed by the JMPR
    clearly show that the current 50 mg/kg limit is reasonable for pre-
    harvest uses where harvest on the day of last application is
    permitted. Additional post-harvest treatment, as permitted in some
    countries, reinforces the need for such a limit. Water washing before
    marketing or consumption would give reasonable assurance that residues
    would be substantially below MRL levels at consumption, even if close
    to them initially.

    Table 4.  Decline of captan residues on sweet cherry fruits remaining 
              on trees, in relation to cumulative rainfall, in 1982 and 
              1983.

                                                                         

                               Date and application rate
                                                                         
                            1982                        1983
                    7x2.4 kg a.i.50% WP/ha     5x2.5 kg a.i.50% WP/ha
                                                                           
    Interval,       Residue     Rainfall       Residue      Rainfall
                    (mg/kg)     (mm)           (mg/kg)      (mm)
                                                                         

    Pre-spray       2.8         --              4.1         --

    Post-spray
    0               6.7          0             26.5          3
    1               5.2          0              9.5          3
    2               2.8          0              7.9          3
    3               4.6          0             11.9          3
    5               5.0          0              9.8          3
    7               4.4          0             13.4          3
    10              1.9         30              --
    11              --                          4.5         42
    14              1.8         30              4.3         55
    Unsprayed       0.01                        0.04
    Mean temp. (14 days): 21.1C                      23.6C
                                                                         

    Table 5.  Decline of captan residues on sour cherry fruits 
              remaining on trees, in relation to cumulative 
              rainfall, in 1982 and 1983.

                                                                         

                                Date and application rate
                                                                         
                           1982                         1983
                    8x3.4 kg a.i.50% WP/ha     4x3.5 kg a.i.50% WP/ha
                                                                           
    Interval,       Residue     Rainfall       Residue      Rainfall
                    (mg/kg)     (mm)           (mg/kg)      (mm)
                                                                         

    Pre-spray       10.4        --             3.5

    Post-spray
    0               13.4         0             29.5          0
    1                8.1         0             31.5          3
    2                6.2        30             18.5          3
    3                7.0        30             10.6          3
    5                9.7        30             12.5          3
    7                8.6        38              8.3          3
    10               5.5        51              --          --
    11               --                         3.0         42
    14               4.8        60              2.1         55

    Unsprayed        0.02                       0.01
    Mean temp. (14 days):  20.8C                    23.6C
                                                                         


        Table 6.  Decline of captan residues on peach fruits remaining on trees in relation to cumulative 
              rainfall in 1981 and 1983.

                                                                                                        

                                               Date, variety and application rate
                                                                                                        
                                              1981                                 1983
                                                                                                        
                                 Redhaven               Garnet Beauty            Redhaven

                               3 x 3 kg a.i.           3 x 3.4 kg a.i.         4 x 3.4 kg a.i.
                                50 %WP/ha                 50 %WP/ha               50 %WP/ha
                                 (Dilute)                (Airblast)              (Airblast)
                                                                                                        
    Interval,               Residue   Rainfall       Residue    Rainfall      Residue    Rainfall
    days                    (mg/kg)   (mm)           (mg/kg)    (mm)          (mg/kg)    (mm)
                                                                                                        

    Pre-spray                3.0        --             1.7        --             9.6       --

    Post-spray

    0                       12.1         0             9.9         0            11.1        0
    1                        6.5        27             7.3         0            10.2        0
    2                         --        --              --        --            11.7        0
    3                        5.8        29              --        --            15.5        0
    4                         --        --             2.7         1              --       --
    5                        6.6        34              --        --            13.1        8
    7                        6.1        34             2.2        42            11.1       14
    10                       4.8        34              --        --             8.9       14
    12                        --        --             2.9        42              --       --
    14                        --        --             1.7        42             2.9       24

    Unsprayed               0.06                        --                      0.24

    Mean temp. (14 days):      19.1C                    20.7C                    23.1C
                                                                                                        

    Table 7.  Captan residues in fruits resulting from supervised trials in Canada
              (Frank et al., 1984; Ritcey et al., 1984)

                                                                                                                                 
                            Application                      Residues, mg/kg, at interval (days) after application
                                                                                                                                   
    Crop             no.       rate                     0       1      2     3      5      7     10     14      15     18-38
    Year                    kg a.i./ha   formulation
                                                                                                                                 

    Apples
    1982-83          3      1.7          50%WP          12 a    3.7          4.3    4.3    3.4   3                     1.9 c
                     15                                 4.2     3.3          4.7    5.4    3.9   3.2    4.2
                     3      3.4                         15.7    8.5          5.1    7.3    3.9   3.2
                     7                                  5.3     3.9          4.4    3.8    4.7   3.3            4.4
                     7                                  5.1     2.8          2.6    3      3.5   2.3            2.2
                     12                                 9.4     4.2          4.1    9.4    6.9   7.1    5.1

    Pears
    1983             3      3.4          50%WP          7.8     5.5          4.7    5.9    3.8   2.1            1.7
    1982             4                                  3.5     3.7          2.2    1.1    2.3   1.1            1.2

    Grapes
    1981             1      2.8          50%WP          3.3     4.5    3.1          2.5    3.4   4.6    3.5
    1982             1                                  1.7     1.5          2.7    2.1    2.1   2.1            0.6
    1981             5                                  8.3     7.3                 4.9    4.1                  3.4    2.4 d
                                                                                                                       2.9 e
    Strawberries
    1982
    Berries b        1      3.4          80%WP          2.4     1.8    0.9          1.3          0.93   0.31
    Foliage                                             17      24     19           21           17     1

    Strawberries
    1983
    Berries b               3.4          80%WP          4.1     4.1    3            0.91         0.8    0.26
    Foliage                                             28      23     21           15           19     8.7
    Calyz                                               4.2     2.5    7.1          5            3      1.9

    Mulch straw                                         97      51     30           45           3.5    21
                                                                                                                                 

    Table 7. (continued)

    a  Apples small (80-100g) in this trial
    b  Residues are the mean of 4 replicates
    c  18 days
    d  21 days
    e  38 days
    

        Table 8.  Residues found in monitoring in The Netherlands, 1981-1983

                                                                                    

    Commodity         Range (mg/kg)   No. in range   Total no.    Codex MRL, mg/kg
                                                                                    

    apple                10-15             2            530             25
    currants             15-20             4            159             20
    endive               3- 5              1             12             15
                         10-15             0
    grape                10-15             1             42             none
                         5-10              6
    pear                 15-20             1            132             25
    raspberry            15-20             2             66             10
                         10-15             7
                         5-10             12
    strawberry           45-54             4            368             20
                         15-20             1
                         10-15            14
    tomato               10-15             2              6             15
                                                                                    
    
    Peaches.  Supervised trials with captan on peaches were also
    available (Northover et al., 1984) and are summarized in Table 6.
    Applications were said to reflect commercial practice. Maximum
    residues in the 1983 trial were 15.5 mg/kg 3 days after the last
    application, with little dissipation during the first 10 days. In the
    1981 studies residues decreased to about one third of the initial
    deposits in 10-12 days. In contrast to cherries, residues in peaches
    were not substantially affected by rainfall except shortly after
    application. Thorough washing removed only a maximum of 50% of the
    initial deposits as contrasted to cherries where very thorough washing
    could remove most of the residue (see "Fate of residues in
    processing"). The data support the Codex limit of 15 mg/kg even for
    the 2-day pre-harvest interval of the country where the trials were
    conducted.

    Grapes.  Supervised trials were conducted in Canada (Frank et
    al., 1984). Data are summarized in Table 7. The rates apparently
    reflect good agricultural practice in that country, although the kg
    a.i./ha rates cannot be equated with kg a.i./1000 l of Table 2.
    Maximum residues ranged from 8.3 mg/kg at day 0 to 4.1 mg/kg at
    Canada's 7-day pre-harvest interval. In two of the trials residues
    were relatively constant from 0 to 10 days. Rainfall affected residue
    levels in two of the three trials. These data indicate that residues
    would probably not exceed 5 mg/kg from Canadian good agricultural
    practice. Additional data and good agricultural practice information
    are needed to support a limit.

    Strawberries.  Data were available from one country (Ritcey et
    al., 1984) and are summarized in Table 7. Applications reflect good
    agricultural practice in the country where the trials were conducted
    and where the pre-harvest interval is 2 days. The interval ranges from
    "nil" to 4 days in other countries for which information was provided.
    Maximum residues on berries were 4.1 mg/kg on the day of treatment and
    3 mg/kg after two days. Residues were much higher on the foliage and
    straw and comparable on the calyx. Rainfall did not appear to reduce
    residues substantially. This was confirmed with simple water rinses
    (See "Fate of residues").

         The current 20 mg/kg limit is more than adequate to accommodate
    Canadian good agricultural practice with single applications, even on
    the last day of application. Data reviewed by the 1978 JMPR clearly
    show that even average residues from glasshouse use (two applications)
    can reach 20 mg/kg and information provided to this meeting confirms
    that use, so there is no basis for lowering the current limit. This is
    supported by monitoring data (see "Residues in commerce or at
    consumption").

         The question has been raised as to why the limit for cherries
    (50 mg/kg) is higher than that for strawberries. No definite
    explanation can be given. Higher residues would be expected on
    strawberries with similar use patterns, in view of the surface area to
    weight ratios. In both cases rainfall can reduce residues
    substantially, although in some trials with cherries it did not.

    Foliage protection may differ between the two. It is more likely that
    uniform residue deposition and representative sampling are more
    difficult with cherries, since it has been shown (Northover et
    al., 1984) that residue levels are higher in the lower outside areas
    of cherry trees.

         It is also noted that residues on strawberries and raspberries
    moving in commerce (see below) sometimes exceed the limits for those
    commodities, which suggests that their MRLs may be too low.

    FATE OF RESIDUES

    In storage and processing

         Some information on the fate of residues in storage or processing
    was available on several commodities. It has already been noted above
    that rainfall can reduce captan residues on apples, but not
    consistently.

         In cherries (Northover et al., 1984) water rinsing for 15 and
    120 seconds removed 70 and 97% respectively of field-incurred
    residues, although it is not clear whether sampling was immediately
    after application or after several days. Storage at 4 or 20C for two
    weeks resulted in no loss of residue.

         The same authors reported on residue losses in peaches. As noted
    above, rainfall did not substantially reduce captan residues on
    peaches. Similarly, 10-second "hand washing" remove a maximum of 50%
    of the initial residue, whereas simple rinses removed substantially
    more from cherries. Even vigorous washing with a stiff bristle brush
    removed only 70% from peaches.

         Residues were also determined in the products of grapes processed
    into wine (Frank et al., 1984). With initial deposits on grapes of
    2.2 mg/kg 8 days after treatment, residues were 1.9 mg/kg on 
    de-stemmed grapes, 16 mg/kg on stems, and <0.01 mg/kg in fermented
    juice and wine.

         For strawberries, several post-harvest treatments have been shown
    to remove residues from initial deposits of 2.4 mg/kg: a 20-minute
    cool water rinse removed 14%; calyx removal gave 36% reduction; calyx
    removal followed by warm and cool water rinses, 63% and calyx removal
    followed by a 5 minute cook, 95%. No losses were reported on storage
    at -20C for 3 months (Ritcey et al., 1984).

    EVIDENCE OF RESIDUES IN FOOD IN COMMERCE OR AT CONSUMPTION

         Substantial data were provided to the meeting on residues in
    commerce. In U.K. monitoring in 1981-1984, residues in apples and
    pears were well below the 25 mg/kg Codex (maximum of 0.9 mg/kg on
    imported apples), and one positive result (0.2 mg/kg) was found in 30
    grape samples. Residues found in Swedish monitoring of domestic and
    imported cherries and potatoes in 1981-1983 were <1.01 mg/kg. In 1983

    Canadian monitoring of domestically grown cherries, residues were
    <0.78 mg/kg in 19 samples taken at the packing plant.

         Substantial monitoring data were provided from The Netherlands on
    a wide range of commodities with and without Codex MRLs. 1981-1983
    data on domestic and imported commodities for which there are Codex
    MRLs and on which residues were found near or above Codex limits are
    given in Table 8.

    Seed Treatments

         Substantial information on Canadian captan seed treatments was
    also provided on many fruits, vegetables and field crops with
    emulsion, WP and suspension formulations, either alone or with other
    presticides.  It was not possible to includes these in this summary. 
    Application rates are typically 50-200 g a.i./100 kg seed.

         In general, monitoring data provided to the meeting give
    reassuraance that current limits are adequate.  The Netherlands' data
    suggest that limits for respberries and strawberries may not be high
    enough if the residues in fact resulted from good agricultural
    practice.  Residues on blackberries (for which there is no Codex MRL)
    also exceeded 20 mg/kg.

    NATIONAL MAXIMUM RESIDUE LIMITS

         National MRLs were reported for four countries:

    Country                Commodity                       MRL, mg/kg
                                                                         
    The Netherlands        apricots                             20
                           currants (black,red,white)           20
                           strawberry                           20
                           tree nuts                            15
                           other fruit                          15
                           spinach                              20
                           other vegetables                     15
                           cereal grains                      0.1*
                           other foods                    0* (0.1)


    *At or about the limit of determination

    New Zealand            fruit                                10
                           vegetables                           10

    Poland                 fruit and vegetables                  6

    Canada                 plums, strawberries,
                           raspberries, peach,
                           pear, tomato, apricot,
                           apple, grape, cranberry,
                           cherry, blueberry                     5
                                                                         

    APPRAISAL

         The meeting considered additional information on agricultural
    practices, and residue data from supervised trials, monitoring,
    processing and storage. Current limits were confirmed for pome fruit,
    blueberries, currants, cherries, peaches and strawberries. Data or
    other information were insufficient to estimate limits for grapes.
    Substantial data were available for Kiwi fruit from one country.

         Rainfall had varying effects on residue levels, depending on the
    commodity, ranging from substantial in some trials on cherries to
    minimal to moderate for strawberries and peaches. In trials on several
    commodities residues were slow to dissipate in the absence of rain.

         Washing was shown to remove over 50% of the residue on some
    commodities and less on others. No losses were evident under cold
    storage. Kiwi fruit residues were slower to dissipate when storage was
    under cool conditions. Residues did not concentrate in grape juice or
    wine.

         Monitoring data provided reassurance that current captan limits
    on many commodities are adequate, although residues on strawberries
    and raspberries suggest good agricultural practice may not have been
    followed or that the limits might be too low.

         The meeting considered the question of the MRL for cherries being
    higher than that for strawberries and concluded that data based on
    good agricultural practice supported current limits. The most likely
    reason for substantial differences in the maximum residue is uneven
    deposition of captan and/or the greater difficulty of representative
    sampling of cherries, although other factors could contribute to the
    difference.

         Questions have also been raised on the definition of the residue.
    In the absence of additional information on the fate of residues, the
    meeting concluded that the current definition, which specified captan
    only, should be retained.

         The meeting examined residue data from supervised trials
    reflecting good agricultural practice on a number of crops and was
    able to estimate the maximum residue levels which are likely to occur
    when captan is used in practice and when the reported intervals
    between last application and harvest are observed. These levels refer
    only to the parent compound.

    RECOMMENDATIONS

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

    Kiwi fruit        20                           2
                                                                       

    FURTHER WORK OR INFORMATION

    Desirable

         Additional information on the number of applications and 
         pre-harvest intervals for Kiwi fruit from the country from which
         data were provided and additional data and information on good
         agricultural practice for captan on Kiwi fruit from additional
         countries.

    REFERENCES

    Northover, J., Frank R., and Braun, H.E. Persistence of Captan on
    1984      Cherry and Peach Fruits. Unpublished document provided by
              the Canadian Government. Proposed for publication in Agric.
              Food Chem. 1984. Contact: Mrs. Jean Stalker, Room 1129, K.W.
              Neatby Bldg., C.E.F. Agriculture Canada, Carling Ave.,
              Ottawa, Ontario, K1A 0C6.

    Frank, R., Northover, J. and Braun, H.E. Persistence of Captan on
    1984      Ontario-grown Apples, Grapes and Pears. Unpublished document
              made available by the Canadian Government. To be submitted
              to Agric. Food Chem. Contact: Mrs. Jean Stalker.

    Ritcey, G., Frank, R., McEven, F.L., and Braun, H.E., Captan Residues
    1984      on Strawberries and Estimates of Exposure to Pickers.
              Unpublished document provided by the Canadian Government.
              Sent to: Archives of Environmental Contamination and
              Toxicology. Contact: Mrs. Jean Stalker.


    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: 1980 evaluations)
       Captan (Pesticide residues in food: 1982 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)