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    TRICHLORFON          JMPR 1978

    Explanation

         Trichlorfon was evaluated in 1971 and 1975 (FA0/WHO, 1972b,
    1976b). Further studies on the spontaneous conversion of
    trichlorfon to dichlorvos in vitro and in vivo were considered
    desirable. The temporary maximum residue limit for tomatoes was
    increased from 0.1 to 0.2 mg/kg at the 1975 Meeting. The limited
    additional data provided for consideration by the present Meeting
    are evaluated in the following monograph addendum.

    EVALUATION FOR ACCEPTABLE DAILY INTAKE

    BIOCHEMICAL ASPECTS

         In experiments with mice using 14C-labelled trichlorfon some
    alkylation of nucleic acids was demonstrated. Based on the urinary
    excretion of 14C-methyl guanine, the alkylation potency of
    trichlorfon was about 4-10 times lower than that of DDVP (Dedek et
    al, 1976). No quantitative data on the methylation of DNA in
    tissues were reported. However, 24 hours after the administration,
    14C-methylguanine was no longer detectable in liver nucleic acids.

    TOXICOLOGICAL STUDIES

    Special studies on mutagenicity

         A dominant lethal test was performed in mice. Groups of male
    mice of two different strains received a single i.p. injection of
    1.6 m.mol/kg trichlorfon (405 mg/kg) or its metabolites (methyl-2,
    2-dichloro-1-1-dihydroxy ethane-phosphonate) (390 kg/kg) and
    dichloroacetaldehyde (170 mg/kg). The animals were noted. The
    average number of living pups was lower in the treated groups then
    in the controls. An increased pre-implantation loss was observed
    only in one strain. No differentiation was made between early and
    late foetal losses. Although the differences with regard to the
    number of living pups were statistically significant within one
    experiment they were within the range of variation seen in a
    different control series (Fisher, et al, 1977).

    Special studies on carcinogenicity

         Three carcinogenicity studies were performed with groups of 30
    AB/Jona mice of each sex. The animals were either treated with oral
    doses of 0 and 30 mg/kg b.w., i.p. doses of 0 and 28.2 mg/kg b.w.
    or were topically treated with 0 and 0.25 ml of a 1% solution
    corresponding to 2.5 mg a.i. per animal. The doses were
    administered twice a week for a period of 75 weeks (2-week
    treatment interruption in the 46th and 47th week). After 80 weeks
    the experiments were concluded.

         The treatment caused reduction of the mean survival time and
    body weight gain in the treated animals. The separate incidences of
    benign and malign tumours respectively and the tumourspecies or
    -localisation did not reveal any significant difference between
    treated or control animals (Teichmann and Hauschild, 1978).

          A summary of carcinogenicity study in mice which were
    administered 100, 300 and 1000 ppm. Trichlorfon in the diet during
    lifetime was available. Except for inhibition of cholinesterase no
    other adverse effects and no increase of the incidences of tumours
    was reported (Anonymous, 1978). In abstract form carcinogenicity
    studies in mice and rats were reported showing an increased
    incidence of tumours at dose levels of 0.03 - 30 mg/kg. Pertinent
    information such as numbers of animals tested, duration of
    treatment, route of administration, nature of and localisation of
    tumours was not given (Petrouskaja and Knzmenko, 1978)

         30 male and 35 female rats received oral doses of 22 mg/kg
    b.w. or i.p. doses of 12 mg/kg b.w. twice a week for up to 90
    weeks. The control groups consisted of 25 animals of each sex. The
    study was terminated after 118 weeks.

         The mean survival time was lower in test animals compared to
    control animals, but, no intergroup differences between treatment
    and control groups were evident with respect to incidences of
    malign and benign tumours, tumour-species and -localisation
    (Teichmann et al., 1978).

         Groups of 23 male and 25 female hamsters were administered
    intraperitoneally 20 mg trichlorfon 1 kg b.w. once weekly for 90
    weeks, 22 males and 23 females served as control. The surviving
    animals were killed at 100 weeks after initiation of the
    experiment. Growth rate was lower in treated animals than in
    controls. By week 80 the survival rate was 50% in treated animals
    and 70% in male and 65% in female controls. The tumour incidence
    was similar in all groups. 5 and 7 in treated males and females
    versus 4 and 5 in the controls (Teichmann and Schmidit, 1978).

    Special study on potentiation

         The simultaneous oral administration of trichlorfon and
    demeton-s-methyl to male rats in equitoxic doses resulted only in
    additive toxicity (Flucke and Kimmerle, 1977).

    Acute Toxicity

                                                                  
    Species   Sex       Route          LC50    Reference
                                       mg/m3
                                                                  
    Rat       M, F      inhalation     533       Kimmerley 1975a
                        (4 hours)
                                                                  

    Sheep

         Treatments of sheep by bathing them in 0.025% trichlorfon
    solution were well tolerated by the animals and only a slight
    reduction of the cholinesterase activity in blood of about 20%
    compared to normal values was observed. Pour-on application with 6%
    trichlorfon solution at dose levels of 36 mg/kg b.w. and 60 mg/kg
    b.w. caused inhibition of the blood cholinesterase activity of 30%
    and 70%. These changes in the enzyme activity were not accompanied
    by clinical symptoms of poisoning (Mieth et al., 1975).

    Short Term Studies

    Rat

         Groups of 10 male and 10 female rats were exposed 6 hours a
    day over a 3-week period (total of 15 exposures) to an atmosphere
    containing trichlorfon at concentrations of 0, 12.7, 35:4 and 103.5
    mg/m3. Exposures to concentrations of up to 35.4 mg/m3 were
    tolerated without any symptoms, whereas rats exposed to 103.5
    mg/m3 showed slightly affected health condition (no details
    available). Body weight gain, parameters of haematological and
    clinical chemistry examinations and urinalyses were not influenced
    at any exposure levels.

         Cholinesterase inhibition of 42, 31 and 22% was found in
    plasma, erythrocytes and brain respectively in male animals at
    103.5 mg/m3; female animals showed dose-dependent inhibition
    values of 39, 26 and 26% at 35.4 mg/m3 and 48, 44 and 47% at 103.5
    mg/m3 in plasma, erythrocyte and brain respectively. The only
    significant alteration in relative organ weight was found in male
    animals showing a dose related increase of the relative
    spleen-weight of about 20 and 25% at the 35.4 and 103.5 mg/m3
    exposure levels. No abnormal histological findings were observed in
    any of the tissue microscopically examined (Kimmerle, 1975b)

    COMMENTS

         The Meeting evaluated data on mouse and rat carcinogenicity
    studies, mutagenicity studies, and the results of studies on DNA
    alkylation.

         A mouse dominant lethal study could not be fully evaluated,
    since the available data did not differentiate between early and
    late foetal death.

         Data on DNA alkylation indicated some activity with regard to
    7-methyl guanine a reaction which has been postulated as indicative
    of carcinogenic activity. However, the Meeting evaluated two rats,
    three mice and one hamster long-term carcinogenicity studies and no
    evidence of tumour induction was observed in any of these studies.
    The Meeting therefore changed the temporary ADI to an ADI.

    TOXICOLOGICAL EVALUATION

    Level causing no toxicological effects

         Rat: 50 ppm in the diet equivalent to 2.5 mg/kg bw

         Dog: 50 ppm in the diet equivalent to 1.25 mg/kg bw

    Estimate of acceptable daily intake for man

         0 - 0.01 mg/kg bw

    RESIDUES IN FOOD AND THEIR EVALUATION

    USE PATTERN

         In addition to the use patterns mentioned in previous
    monographs, the use of trichlorfon for controlling lepidopterous
    larvae, sawfly in apples and pears shortly before harvest (Anon.,
    1978d) and the post-harvest use for controlling vinegar fly (Anon.,
    1978a) have been reported.

    RESIDUES RESULTING FROM SUPERVISED TRIALS

         Residues resulting from post-harvest treatment of sultanas are
    given in Table 1.

        TABLE 1. Residues resulting from post-harvest treatment of sultanas

                                                                                        

    Dosage                  No. of           Days after             Residue, mg/kg
                            treatments       last application
                                                                                        

    10 g/100 kg                 1                  15               0,15; 0,05; 0,1; 0,1
                                                                    0,15; 0,1; 0.05; 0,05

                                2                   9               0,25; 0,15; 0,15; 0,25; 0,1
                                                                    0,15; 0,05; 0,1; 0,10
                                                                                        
    
         Results of supervised trials carried out on various plants as
    foliar treatment are summarized in Tables 2 and 3 (Anon., 1978,c,d;
    Nihon Tukushu, 1978).

    FATE OF RESIDUES

    In animals

         Lactating cows were treated with different formulations of
    trichlorfon at dose rates of 20-45 mg/kg. The trichlorfon residues
    reached a maximum of 0.6-6 mg/kg in the blood depending on the
    formulation during the first 12 hours. The residue in the milk is a
    function of the trichlorfon concentration in the blood and the
    equilibration in rapid (Table 4). The total residue detected contained
    less than 5% of the metabolite dichlorvos in the blood and less than
    2% in the milk.

         The milk of each of ten cows contained less than 0.05 mg/kg of
    trichlorfon residue 48 hours after a dermal pour-on application of
    neguvon solution at a dose rate of 50 mg/kg (Juskiewicz, 1974).

         Oral administration of 30 mg/kg trichlorfon resulted in a maximum
    residue of 0.55 mg/kg in milk one hour after treatment. The level was
    0.007 mg/kg after 24 hours. Small amounts of dichlorvos,
    trichloroethanol and dimethyl phosphate were detected in the milk 3
    hours after treatment but none was detectable after 9 hours (Nakahara,
    1972).

         Filatov et al., (1972) found that 0.32% of trichlorfon applied
    dermally to cows was excreted with the milk in the first 24 hours. The
    residues in the milk decreased rapidly after treatment trichlorfon;
    1 h 1.7 mg/kg; 24 h 0.2 mg/kg; 36-96 h traces; dichlorvos 1 h 0.58
    mg/kg; 3 h 0.29 mg/kg; 6-24 h traces.

         The milk fat contained considerably lower residues than the whole
    milk, indicating that trichlorfon is hydrophilic.

         It should be pointed out that the evaluation of trichlorfon in
    1971 contains a misinterpretation of the work of Arthur and Casida on
    the metabolism of butonate in rats stating that "45% of the
    administered dose was found in the fat." In fact the amount of
    butonate and its metabolite trichlorfon was very low, but the ratio of
    the compounds detected in the fat was as follows: butonate 17.9%,
    trichlorfon 44.6%, hydrolysis product 37.5%. No measurement of
    residues in the fat after direct treatment with trichlorfon was
    mentioned in the papers available for evaluation.

         Subcutaneous treatment of pigs with trichlorfon resulted in
    somewhat lower residues in the meat and small intestine (ileum) than
    in the blood. Dichlorvos was the only metabolite found in the blood
    and ileum (Table 5; Dedek and Schwarz, 1969).


        TABLE 2. Residues resulting from supervised trials.

                                                                                                                                         

    Crop             Country   Year   No.   Rate       Formulation
                                            kg ai/ha                 1-3        4-6         7-10         13-15        18-21      27-29
                                            or as
                                            specified
                                                                                                                                         

    Cabbage(1)       Japan     1975   6     2-5        EC 50%                   0.14-0.05   0.08-0.03
                     Japan            8                                         0.23-0.07   0.05-0.03
                     Finland                           not                      0.6                      0.5          0.4        0.2
                                                       stated

    Chinese(1)       Japan     1972   3     2          EC 50%                                            0.13-0.04    0.09-0.02
    cabbage
                     Japan            5                                                     0.06         0.05
                     Japan            6                                                     0.13         0.086

    Citrus(1)        Japan     1973   5     3          EC 50%                                                                    <0.003

    Eggplant(1)      Japan     1972   5     1          EC 50%                   0.02-0.03   0.01-<0.005  <0.005
                                      8                                         0.02        0.007-<0.005 <0.005

    Japanese(1)      Japan     1975   3     0.063%     EC 50%        0.57-0.53              0.36         0.3-0.25
    kaki persimmon                          18 l/tree

    Japanese         Japan     1971         2          EG 50%        2.76-0.22  0.26-0.09   0.07-0.02
    radish leaf                       5
    root(1)                                                          0.12-0.07  0.07-0.03   0.05-0.01

    leaf                              8                EC 50%        1.4-0.9    0.77-0.1    0.09-0.03
    root(1)                                                          0.12-0.008 0.04-0.03   0.04-0-01

    Potatoe          Japan     1976   6     2          EC 50%                               0.03-0.02    0.02-<0.008

    Black            Finland                1.3 g/     not                                               2.6                     0.2
     currant(1)                             plant      stated

    TABLE 2. (Cont'd)

                                                                                                                                         

    Crop             Country   Year   No.   Rate       Formulation
                                            kg ai/ha                 1-3        4-6         7-10         13-15        18-21      27-29
                                            or as
                                            specified
                                                                                                                                         

    Raspberry        Finland          2     0.8                                                          5.6
                                            linean
                                            0.5-0.6    not                                                            0.7-2.9
                                            g/plant    stated

    Red currant      Finland                16 g/      not                                               25           12
                                            plant      stated

    Strawberry       Japan     1976   3     2          EC 50%                                            1.4          0.33
                                      5                                         4.6                      0.74

    Strawberry       Japan            3     3          EC 50%                                            2.12         0.46
                                      5                                                     3.31         1.06
                                      1     1.6-2.4                                                                   0.02

    Sugarbeet(1)     Japan     1975   6     1.5        EC 50%                               0.05-0.02    0.04-0.02
                                      8                                                     0.04-0.02    0.024-0.02
                     Finland          2     0.64       not                                                                       0.05
                                                       stated                                                                    (48 days)

    Watermelon(1)              1976   6     2          EC 50%                               0.008
                                                                                                                                         

    (1) These crops were analyzed for dichlorvos but none was detected (limit of detection 0.005 mg/kg). Low levels of dichlorvos were found
          in strawberry (see Table 7).

    TABLE 3. Residues resulting from supervised trials.

                                                                                                                                         

                                       Application                   Residues (mg/kg)1 at intervals (days) after application
    Crop           Country     Year    No.   Rate,     Formulation
                                             kg ai/ha                0/1          2           3      4-5      7-8            9-10
                                                                                                                                         

    Apple,         Netherland  1976    1     1.2       WP 80%                                                                0.8
    winston                                                                                                                  (0.6-0.9)

    Apple,         Netherland  1976    1     1.2       WP 80%                                                                1.4
    golden                                                                                                                   (0.-1-1.9)

    Brussels       Netherland  1970    3     1.2       WP 80%        0.26         0.26                        0.1
    sprouts                                                          (0.15-0.4)   (0.15-0.4)                  (0.08-0.13)

                               1970    4     1.2       WP 80%        0.29         0.1                         0.05
                                                                     (0.08-0.9)   (0.08-0.1)                  (0.03-0.05)

    Carrot         Hungary     1976    1     0.8       WP 50%        0.5                      0.1    0.02     0.01           0.012

    Green          Hungary     1976    1     1.0       WP 50%        0.13         0.06        0.05   0.03     0.02           0.02
    pepper                                                                                                                   (14-16 days)

    Kale           Netherland  1976    1     1.0       WP 80%                                                 0.26
                                                                                                              (0.12-0.33)

    Kohlrabi       Netherland  1976    1     1.0       WP 80%                                                 0.02
                                                                                                              (0.01-0.02)

    Parsley        Hungary     1976    1     0.8       WP 50%                                 0.2    0.02     0.01           0.012

    Red cabbage    Netherland  1976    1     1.0       WP 80%                                                 0.05
                                                                                                              (0.03-0.05)

    Savoy          Netherland  1976    1     1.0       WP 50%                                                 0.2
    cabbage                                                                                                   (0.12-0.36)

    TABLE 3. (Cont'd)

                                                                                                                                         

                                       Application                   Residues (mg/kg)1 at intervals (days) after application
    Crop           Country     Year    No.   Rate,     Formulation
                                             kg ai/ha                0/1          2           3      4-5      7-8            9-10
                                                                                                                                         

    Spinach        Netherland  1976    1     1.0       WP 80%                                        4.0
                                                                                                     (3.4-5.3)

                               1976    1     1.0       WP  80%                                       3.2
                                                                                                     (2.1-6.2)
                                                                                                                                         

    1 Average of 3 or 4 samples
    2 Average of 7 samples

    TABLE 4. Residues in the blood and milk of cows treated with trichlorfon.

                                                                                                                      

    Treatment                     Dosage,           Sample      Residue (mg/kg(at intervals (h) after treatment
                                  mg ai/kg bw                                                                         

                                                                2         4         6         8         10        24
                                                                                                                      

    Intramuscular,                25                blood       4-6       2-4       1-2       -         -         -
    50% in polyethylene

    glycol                                          milk        2.4       1.3       0.7       0.5       0.25      0.1

    Pour-on, 2%                   20                blood       2         0.5       0.3       0.2       0.1       0.05
    in mineral oil                                  milk        1.2       0.5       0.3       0.2       0.1       0.05

    Pour-on, 2%                   20                blood       0.3       0.5       0.55      0.6       0.6       0.3
    in vegetable
    oil                                             milk        0.2       0.3       0.35      0.35      0.2       0.1
                                                                                                                      
    

         Sheep were treated with an aerosol formulation of trichlorfon at
    49/m3 and kept in a closed pen for 3 hours. The animals were
    slaughtered 1, 3, 5, 7 and 10 days after the treatment (Nepoklonov and
    Bukstynor). The residues of trichlorfon and dichlorvos was determined
    by TLC. The results are summarized in Table 6.

    In plants

         Strawberries, sugar beets and radishes were treated with
    trichlorfon and analysed for both trichlorfon and dichlorvos (limit of
    detection 0.005 mg/kg). Dichlorvos was detected in strawberries but
    only in the leaves of radishes and sugar beets. The dichlorvos residue
    was 20-30 times lower than that of trichlorfon and disappeared at a
    rate similar to the parent compound (Table 7).

    RESIDUES IN FOOD MOVING IN COMMERCE

         The residues found in samples taken from the yield at harvest in
    Hungary and known to have been treated are summarized in Table 8. 90%
    of the samples contained residues below 0.02 mg/kg.

         In routine market surveys in Australia, low residues of
    trichlorfon (< 0.1 mg/kg) were found in 9% of the samples analysed
    during a 12-month period in 1977-78 (Anon., 1978a). No trichlorfon
    residues were detected in 66 total diet samples in England in 1966-67
    (Abbott et al., 1970).

    NATIONAL MRLs REPORTED TO THE MEETING

    The following new or amended MRLs have been reported to the Meeting.

    METHODS OF ANALYSIS

         A well established multi-residue method (based on acetone
    extraction and partition of the diluted extract with methylene
    chloride) can be recommended for regulatory purposes
    (Methodensammulung zur Rückstandsanalytik, 1976).

    APPRAISAL

         The new data available for evaluation support the conclusions of
    the previous Meetings and indicate that the concentration of
    trichlorfon in various organs after direct application to animals
    largely depends on the treatment procedure and the formulation used.
    The residue level in organs and tissues reached its maximum within 12
    hours of dosing in cows and pigs. Only low residues were detectable
    after 24 hours. The fat of milk contains much lower residue than the
    whole milk since trichlorfon is hydrophilic. Trichlorfon was detected
    in organs and tissues of sheep 7 days after aerosol treatment.


        TABLE 5. Residues of trichlorfon and its metabolite dichlorvos in pigs after subcutaneous treatment (25 mg/kg).

                                                                                                               

    Sample                     Residue (mg/kg) at intervals (h) after treatment
                                                                                                               

                     0.5       1         1.5       2            3           4         6         12        24
                                                                                                               

                                                   trichlorfon

    Blood                      9-10                5-6          4-5         3-4       1-2       0.2       -

    Meat                       6                   5            3-4         2-3       1         0.1       <0.01

    Ilium                      5-6                 5-6          3           1.5       1         -         -

                                                   dichlorvos

    Blood            0.5-1               0.3-0.5                <0.05

    Ilium            0.3-0.5             0.2-0.4                <0.1
                                                                                                               

    TABLE 6. Residues of trichlorfon and dichlorvos in organs and tissues of sheep treated with trichlorfon aerosol.

                                                                                                                                         

    Sample                 Residue (mg/kg) at intervals (days) after treatment
                                                                                                                                         

                         1                        3                        5                        7                        10
              Trichlorfon  Dichlorvos  Trichlorfon  Dichlorvos  Trichlorfon  Dichlorvos  Trichlorfon  Dichlorvos  Trichlorfon  Dichlorvos
                                                                                                                                         

    Muscle        2.3          0           0.8           0          0.6          0          Trace          0      0            0

    Heart         1.7          0           0.3           0          0.3          0

    Liver         1.7          0           1.4           0          1.1         0.8          0.6

    Spleen         2           0           0.8           0          0.3          1          Trace          0      0            0

    Lung          1.7          0           0.3           0         Trace         0

    Kidney        2.3          0           0.5          0.8         0.6         1.2          0.3

    Brain         1.4          0           0.3           0          0.3          0            -

    Milk          0.8          0           0.6           0          0.4          0            -
                                                                                                                                         

    TABLE 7. Trichlorfon and dichlorvos residues in crops treated with trichlorfon.

                                                                                                   

    Crop                Dosage         No. of         Days after          Residue, mg/kg
                        kg a.i./ha     treatments     last application    Trichlorfon    Dichlorvos
                                                                                                   

    Strawberry          2-3            3              13-14               2.1-1.4        0.08

                                                      20-21               0.46-0.33      <0.005

                                       5              6-7                 4.6-3.3        0.23-0.1

                                                      13-14               1.1-0.74       0.04-0.02

    Sugar beet          1.5            6              6-7                 0.24-0.06      0.02-0.01

                                                      13-14               0.07-0.02      <0.01

                                       8              6-7                 0.29-0.05      0.06-0.02

                                                      13-14               0.08-0.02      0.02-0.003

    Radish (leaf)       1.5-2          8              1                   1.4-0.22       0.006

                                                      5                   0.77-0.1       <0.004

                                                      10                  0.09-0.03      <0.004
                                                                                                   
    

        TABLE 8. Residues of trichlorfon in samples taken from fields at or about harvest.
               (Hungary; MRL = 1 mg/kg)

                                                                                           

    Crop                No. of         No. of samples and their mean residues in the ranges
                        samples                  mg/kg shown *
                                                                                           

                                         0.5 - 1            0.02 - 0.5         0.02
                                       No.     Mean        No.     Mean        No.
                                                                                           

    Apple                184           1       0.54         9      0.14         174

    Apricot               40           2       0.69         4      0.21          34

    Bean                  18           1       0.52         0      0.            17

    Cabbage               83           0       0.0         23      0.10          60

    Carrot                37           0       0.0          1      0.04          36

    Cauliflower           36           2       0.60         5      0.19          29

    Cherry               106           1       1.0          8      0.15          97

    Cucumber              21           0       0.0          0      0.0           21

    Grape                118           0       0.0          7      0.18         111

    Kale                  40           3       0.71         6      0.15          31

    Kohlrabi              33           1       0.6          7      0.16          25

    Lettuce                9           1       0.78         1      0.12           7

    Paprika               53           0       0.0          3      0.06          50

    Parsley               20           0       0.0          1      0.02          19

    Peach                 67           1       0.58         6      0.15          60

    Pear                  54           0       0.0          4      0.18          50

    Plum                  42           1       0.8          1      0.08          40

    Potatoe              212           1       0.95        17      0.14         194

    Radish                18           0       0.0          1      0.07          17

    TABLE 8. (Cont'd.)

                                                                                           

    Crop                No. of         No. of samples and their mean residues in the ranges
                        samples                  mg/kg shown *
                                                                                           

                                         0.5 - 1            0.02 - 0.5         0.02
                                       No.     Mean        No.     Mean        No.
                                                                                           

    Red currant           16           0       0.0          2      0.09          14

    Sour cherry           51           0       0.0         13      0.17          38

    Spinach               15           0       0.0          0      0.0           15

    Strawberry            93           4       0.72         2      0.03          87

    Tomatoe               53           0       0.0          1      0.05          52
                                                                                           

    * No residues above 1 mg/kg were found.


    TABLE 9. National MRLs reported to the Meeting

                                                                                               

    Country                                 Commodity                               MRL, mg/kg
                                                                                               

    Australia                               Dried fruits                            2

                                            Bananas, peaches                        0.2

                                            Brussels sprouts

                                            Caluiflower, kale

                                            Sweetcorn, celery

                                            Beetroot

                                            Raw cereals                             0.1

                                            Vegetables (except those above)         0.1

                                            Milk, sugarbeet                         0.05

                                            Sugar cane                              0.05*

    TABLE 9. (Cont'd.)

                                                                                               

    Country                                 Commodity                               MRL, mg/kg
                                                                                               

    the Netherlands

                     Established            Fruit                                   0.5

                                            Vegetables                              0.5

                     Under Consideration

                                            Raw cereals                             0.2

                                            Sugar beet                              0.05

                                            Peanut (shelled)                        0.1

                                            Milk and milk products                  0.05

                                            Meal and meal products                  0.1

                                            Other food commodities                  0.05*

    Sweden                                  Fruit and vegetables                    0.5
                                                                                               

    * At or about the limit of determination.

    
         After treating strawberries, sugar beets and radishes with
    trichlorfon, residues of dichlorvos were detected In strawberries but
    only in the leaves of radishes and sugar beets. The level of
    dichlorvos was 20-30 times lower than that of trichlorfon.

    RECOMMENDATIONS

         With the establishment of an ADI, the previously recommended
    temporary MRLs are converted to MRLs.

         In the light of new use patterns and residue data from supervised
    trials on various commodities some previous recommendations are
    amended and additional MRLs are recommended.

    Commodity                 MRL, mg/kg    Pre-harvest (pre-slaughter)
                                            intervals on which
                                            recommendations are based
                                            (days)
    Amended recommendations

    Apple                    2              10
    Strawberries             1              21
    Cabbage                  0.5            10

    Additional recommendations

    Grapes                   0.5            14
    Meat of sheep            0.1             7
    Radishes                 0.1            10
    Parsley                  0.05           10
    Carrots                  0.05           10
    Eggplants                0.05           14

    FURTHER WORK OR INFORMATION

    Desirable

    1.   Submission of full reports of carcinogenicity studies available
    to the Meeting in summary form only and therefore not considered.


    2.   Further studies on the spontaneous conversion of trichlorfon to
    dichlorvos in vitro and in vivo and of the possible intermediates
    involved.

    3.   An adequate dominant lethal study in mice.

    4.   Residue data from recent supervised trials or from selected
    surveys on commodities on which trichlorfon is known to be used, where
    there is evidence of good agricultural practice.

    REFERENCES

    Abbott, D.C., Crips, S., Tarrant, K.R., Tatton, J.O'G. Pesticide
    (1970)              residues in the total diet in England and Wales,
                        1966-1967. Pestic. Sci. 1; 10-13.

    Arthur, B.M., Casida, J.E. Biological activity of several
    (1958)              O-O-dialkyl alpha-acyloxyethyl phosphonates J.
                        Agr. Food Chem. 6; 360-365.

    Anonymous Unpublished summary from the Institue of Comparative and
    (1978)              Human Toxicology, Albany (USA) submitted by Bayer.

    Anonymous Information on trichlorfon from Australia.
    (1978a)

    Anonymous Information on trichlorfon from Finland.
    (1978b)

    Anonymous Information on trichlorfon from the Netherlands
    (1978c)

    Anonymous Information on trichlorfon from Sweden.
    (1978d)

    Dedek, W., Koch, H., Uhlenhut, G., Bröse, F. Zur Kenntnis der
    (1969)              Umsetzung von 3H-trichlorphon zu DDVP,
                        Zeitschrift f. Naturforschung, Serie B. 24
                        663-664.

    Dedek, W., Schwarz, H. Zur Rückstandsbildung von
    (1970)              32p-markierten/Organophosphorinsktiziden bei
                        landwirschaftlichen Nutztieren/Archir
                        experimentelle Veterinaermedizin 24 719-726.

    Dedek, W., Lobs, K.H., Fischer, G.W. and Schmidt, R. Alkylation
    (1976               of guanine in Mice in vivo by Organophosphorus
                        Insecticides. I. Trichlorphone and Butonate. Pest.
                        Biochem, Physiol. 6, 101-110.

    FAO/WHO 1975 evaluations of some pesticides residues in food.
    (1977)              IAG.P 1975/M/13.

    FAO/WHO 1971 evaluations of some pesticides residues in food.
    (1972)

    Filatov, G.V., Sivokhin, P.A., Metelitsa, V.K. Trichlorfon
    (1972)              excretion in milk. Veterinariya Moscow/5 102.


    Flucke W. and Kimmerle, G. Trichlorfon and Demeton-S-methyl,
    (1977)              Untersuchungen zur akuten Toxizität nach
                        gleichzeitiger Verabreichung beider Wirkstoffe.
                        Unpublished report from Bayer AG, No. 7066,
                        submitted by Bayer AG.

    Juskiewicz, T., Kosmala, K., Zumdrit J. Trichlorfon residues in
    (1974)              milk following dermal application of neguvon
                        (Bayer) against hypodermo Bovis. Bull. vel. Inst.
                        Pulawy 18 93-96.

    Kimmerle, G. Acute Inhalation toxicity study on rats. Unpublished
    (1975a)             report from Bayer AG. Unpublished report from
                        Bayer AG, No. 5581, submitted by Bayer AG.

    Kimmerle, G. Subacute inhalation toxicity study on rats.
    (1975b)             Unpublished report from Bayer AG, No. 5582,
                        submitted by Bayer AG.

    Mieth, K., Beier, D. and Losch, K. Untersuchen mit
    (1975)              Phosphorsäureesterpräparaten beim Rind, Schwein
                        und Schaf unter besonderer Berücksichtigung der
                        Cholinesteraseaktivität. 4. Mitteilung: Der
                        Einsatz von Phosphorsäurepräparaten und deren
                        Einfluss auf die Acetylcholinesteraseaktivität
                        beim Schaf. Arch. Exp. Veterinärmed. 29, 501-517.

    Methodensammlung zur Rückstandsanalytik von Pflanzenschutzmitteln
                        Liefenung 1976 s-8 Verlag Chemie GmbH,
                        Weinheim/Bergstrasse F.R.G.

    Nakahara, T. et al. Residues of trichlorfon and its metabolites in
    (1972)              fresh milk. BotyuKagaku 37 149-154/in
                        Japanese/English abstract was used only.

    Nihon Tokushu, Noyaku Seizo, K.K. Analytical test results on
    (1978)              residues of trichlorfon.

    Nepoklonov, A.A., Bukstynov, V.I. On terms of chlorophos release
                        from the sheep organizm in aerosol treatment UOK
                        619:615.777/779:61Y.484:541.12.213:636.32/38.

    Petrouskaja, O.G. and Kuzmenko. N.M. Unpublished summary from the
    (1978)              All-Union Research Institute for Hygiene and
                        Toxicology, Kiev, USSR.

    Teichmann, B. and Hauschild, F. Zur Prüfung von
    (1978)              O.O-Di-methyl(1-hydroxy-2,2,2-trichloräthyl)-phosp
                        onat (Trichlorphon) auf kanzerogene Wirkung in
                        Mäusen durch orale (ösophago-gastrale Sondung),
                        intraperitoneale und dermale Applikation. Arch.
                        Geschwulstforschung 48, 301-307.

    Teichmann, B., Hauschild, F. and Eckelmann, A. Zur Prüfung von
    (1978)              O.O-Dimethyl(1-hydroxy-
                        2,2,2-trichloräthyl)-phosphonat (Trichlorphon) auf
                        kanzerogene Wirkung in Ratten durch orale
                        (ösophago-gastrale Sondung) und intraperitoneale
                        Applikation. Arch, Geschwulstforschung 48,
                        112-119.

    Teichmann, B.       and Schmidt, A. Zur Prüfung von
    (1978)              O,O-Dimethyl(1-hydroxy-2,2,2-trichloräthyl) 
                        phosphonat (Trichlorphon) auf kanzerogene Wirkung
                        in syrischen Goldhamstern (Resocricetus anratus
                        Waterhouse) durce intraperitoneale Iniekton.
                        Arch. Geschmulstforschung 48, 718-721.
    


    See Also:
       Toxicological Abbreviations
       Trichlorfon (EHC 132, 1992)
       Trichlorfon (HSG 66, 1991)
       Trichlorfon (JECFA Food Additives Series 51)
       Trichlorfon (WHO Food Additives Series 45)
       TRICHLORFON (JECFA Evaluation)
       Trichlorfon (WHO Pesticide Residues Series 1)
       Trichlorfon (WHO Pesticide Residues Series 5)
       Trichlorfon (IARC Summary & Evaluation, Volume 30, 1983)