IPCS INCHEM Home


    PESTICIDE RESIDUES IN FOOD - 1983


    Sponsored jointly by FAO and WHO






    EVALUATIONS 1983





    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
    Geneva, 5 - 14 December 1983

    Food and Agriculture Organization of the United Nations
    Rome 1985

    TRIAZOPHOS

    RESIDUES

    Explanation

         Triazophos was first evaluated in 1982 when a temporary
    acceptable daily intake (ADI) was estimated on the basis of the
    toxicological data available (FAO/WHO 1982)1. At that time, the
    information on use patterns, residues, fate of residues and methods of
    analysis was not evaluated. The following monograph presents the
    evaluation of the additional information and makes recommendations for
    maximum residue limits (MRLs).

    RESIDUES IN FOOD AND THEIR EVALUATION

         Information was available on the purity of the technical grade
    active ingredient used in the formulation of triazophos pesticides.
    This contains a minimum of 92 percent triazophos, together with
    varying amounts of five substances derived from intermediates used in
    the synthesis and with phosphorylated and unphosphorylated resins
    produced in the reaction.

         The Meeting held the view that none of these impurities, other
    than sulfotep, were of toxicological significance.

         Triazophos, a contact and stomach poison for insects and mites,
    is registered in many countries of the American continents, Africa,
    Asia and Europe. It is mostly marketed as a 40 percent emulsifiable
    concentrate (E.C.); other registrations include 15 percent and 25
    percent liquid formulations for ULV application, granules and a 30
    percent wettable powder (W.P.).

         It has a broad spectrum of activity and a good initial and
    residual effect against a variety of insects and mites that damage
    crops. It exhibits ovicidal action against summer eggs of mites and
    eggs of certain insects. It is especially effective against the summer
    fruit tortrix moth (Adoxophyes reticulana), citrus psyllid (Trioza
    sp.) and the diamond-back moth (Plutella xylostella.  Earias sp.,
    Pectinophora sp., Spodoptera sp. and Bemisia sp. are also
    killed.

         Triazophos controls a large number of insect pests and mites that
    damage agricultural, horticultural and forest crops. The main fields
    of application are cotton, sugarcane, maize, potatoes, vegetables,
    fruits, coffee and ornamentals.


              

    1  See Annex 2 for FAO and WHO documentation.

         The registered uses are listed in Table 1, where application
    rates/concentrations, pro-harvest intervals and established MRLs are
    indicated. In addition to the information on use patterns from the 15
    countries listed in Table 1, the Meeting received comprehensive
    details of approved use patterns in a further 11 countries.

    RESIDUES RESULTING FROM SUPERVISED TRIALS

         Reports of 318 residue trials, together with corresponding
    analytical results, were reviewed. These are summarized in Table 2,
    where crops have been arranged into groups corresponding to the Codex
    classification of food groups. Table 2 contains information about the
    country where trials were conducted and a summary of the rate of
    application, number of treatments, preharvest interval, plant part
    analysed, limit of determination in mg/kg, number of analyses, number
    of residues below limit of determination and residues found above this
    limit.

         Where the analysis was made separately on the peel and pulp of
    fruit with inedible peel, the residue levels in the whole fruit have
    been estimated from knowledge of the average ratio of pulp to peel.

         Results of some typical trials on crops where residues were found
    at levels significantly above the limit of determination have been
    summarized in Table 3. From this tabulation it is possible to
    determine the rate of disappearance of residues as well as the
    residues remaining at the time of normal harvest. The following
    observations have been made.

    Cereals

    Maize

         No residues could be determined in any of the analyses. The limit
    of determination varied from 0.005 to 0.07 mg/kg in the different
    trials.

    Wheat and oats

         The use of triazophos on wheat and oats is of minor importance.
    In two trials, residues of 0.02 mg/kg were determined using an
    analytical method with a limit of determination of 0.01 mg/kg.

    Fruit

    Apples and pears

         The results obtained are variable owing to changing application
    conditions. A residue level of 0.2 mg/kg was not exceeded when 0.3 kg
    a.i./ha was applied as a total of four applications at fortnightly
    intervals and a pre-harvest interval of 50 days. The same applies when
    an amount of 0.6 kg a.i./ha was used with a pre-harvest interval of 80
    to 90 days.


        Table 1.  Registration Status of triazophos1

                                                                                                                 

    Country       Dose                Crop                 Pre-harvest     MRLs             Remarks
                  (a.i.)                                   Interval        (mg/kg)
                                                           (days)
                                                                                                                 

    Brazil        400-600g/ha         cotton               28              0.03*            limit of detection
                                      citrus               60              0.002*
                                      coffee               14              0.01*

    Belgium       30-80g              fruit culture        75              0.1 for
                  in 100 l water                                           apples and
                  240g/ha             sugarbeet            45              pears

    Czechoslovakia
                  400g/ha             potatoes             14              -                aerial application
                  400/ha              rape                 14              -                only before flowering
                  0.6g/l              fruit                -               -
                  800g/ha             sugarbeet and        -               -                only before flowering
                                      fodder beet          -               -

    Denmark                           ornamental           -
                                      plants
                                      pome fruits          2 months

    Federal       0.2g/l              cauliflower          35              0.2
    Republic      240g/ha             bushybeans           14              0.2
    Germany       240g/ha             field beans          21              0.2
                  240g/ha             potatoes             14              0.05
                  240g/ha             sugarbeet            42              0.05
                  600-l 200g/ha       maize                -               0.05
                  0.6g/l,             fruit culture        -               0.2              only one application
                  240-360g/ha         forest               -               -                 after flowering
                  0.4g/l              ornamental           -               -
                                      plants
                                                                                                                 

    Table 1. (continued)

                                                                                                                 

    Country       Dose                Crop               Pre-harvest    MRLs        Remarks
                  (a.i.)                                 Interval       (mg/kg)
                                                         (days)
                                                                                                                 

    Great         300-1 000g/ha       apples             28             -
    Britain                           pears              28             -
                                      strawberries       28             -
                                      raspberries        28             -
                                      sugarbeet          28             -
                                      maize              28             -
                                      carrots            28             -
                                      leaf brassicas     28             -
                                      field beans        28             -
                                      ornamentals        28             -
                                      potatoes           28             -
                                      broad beans        28             -
                                      celery             28             -
                                      leeks and          28             -
                                      parsnips
                                      cereals            28             -
                                      root brassicas     28             -
                                      peas               21             -

    Hungary       400-1 600g/ha       fruit culture      21             0.1
                  400-480g/ha         viticulture        21             0.1
                  400g/ha             tobacco            21             0.1
                  280-400g/ha         soybean            21             0.1
                  400g/ha             maize              21             0.1
                  280g/ha             rape and           21             0.1
                                      mustard
                  400g/ha             vegetables         21             0.1

    Indonesia     0.3-0.6g/l          Chinese            14             -
                                      cabbage
                  1 kg a.i./ha        cotton             14             -
                                                                                                                 

    Table 1. (continued)

                                                                                                                 

    Country       Dose                Crop               Pre-harvest    MRLs        Remarks
                  (a.i.)                                 Interval       (mg/kg)
                                                         (days)
                                                                                                                 

    Iran          0.6g/l              pistachio nuts     14             -

    Malaysia      380g-400gg.i/ha     rice               14             -

    The Netherlands
                  0.4-0.6g/l          strawberry         -              0.01        only before flowering
                                      apples             -              0.01
                                      pears              -              0.01        only before flowering

    New Zealand   300-400g/ha         fodder
                                      brassicas          14

    Poland        240g/ha             field beans        28             -
                  240g/ha             sugarbeet          42             -
                  120-240g/ha         brassicas          -              -
                  360g/ha             potatoes           14             -

    Spain         0.6-0.8g/l          citrus             30             -
                  0.6-0.8g/l          fruit culture      40
                  0.3-0.6g/l          cotton             -
                  0.6-0.8g/l          maize              -
                  0.6-0.8g/l          potatoes           -
                  0.6-0.8g/l          hazelnuts          -

    South Africa  5g in 100 l         oranges and        56*            2.0         *if last spray at golf
                  water               grape fruit                                   ball size
                  up to 300g          pro-rated
                  in 100 l water      valencias          1*             2.0         *single spray at 60ml/
                                                                                    100 l water

                                                                                                                 

    Table 1. (continued)

                                                                                                                 

    Country       Dose                Crop               Pre-harvest    MRLs        Remarks
                  (a.i.)                                 Interval       (mg/kg)
                                                         (days)
                                                                                                                 

                                                         4*             2.0         *double sprays at 60ml/
                                                                                    100 l five weeks apart

                                      Lemons             1*             2.0         *shortly before harvest
                                                                                    single spray at 60 ml/
                                                                                    100 l water

    South Africa  5g in 100 l         lemons             4*             2.0         *if second spray at
                  water                                                             60ml/is applied 5
                  up to 300 g                                                       weeks later
                  in 100 l water
                                      all citrus         70*            2.0         *when more than 285ml/
                                                                                    100 l used per crop
                                                                                    including sprays for
                                                                                    thrips

                                      maize              21             0.1*        *green maize

                                      bananas            7              2.0
                                                                                                                 

    1    This summary includes only countries where MRLs and/or waiting periods are established.
         A further group of countries have approved the use of triazophos. Those include 
         Bulgaria, Colombia, Ecuador, El Salvador, Egypt, Korea, Romania, Thailand, United 
         Kingdom and Zimbabwe.

    Table 2.  Triazophos Residues in Crops from Supervised Trials

                                                                                                                                           

    Crop/          Rate of         No. of       Preharvest    Plant        Limit of         No. of     No. of residues    Residues above
    Country        application     treatments   interval      Part         determination    analyses   below limit of     limit of 
                   (kg a.i./ha)                 (days)        analysed     (mg/kg)                     determination      determination
                                                                                                                                           

    Cereals
    -Maize         1.2             1            28-68         grain        0.005            3          3
    Federal        0.045-0.2       1-2          28-171        grain        0.01             3          3
    Republic       1.2             1            60-69         grain        0.04             4          4
    Germany        1.2             1            14            grain        0.05             1          1
                   0.6-1.2         1-2          61-65         grain        0.07             3          3

    France         1.2             1            91            grain        0.07             1          1

    -Oats          0.8             1            93            grain        0.03             1          1
    Federal
    Republic
    Germany

    -Wheat         0.4             1-3          28-30         grain        0.01             1          -                  0.02
    Brazil

    Fruits
    -Apple         0.2-0.81        2            90            whole fruit  0.01             2          -                  0.01-0.1
    Argentina      0.2-0.4         1-2          45-56         whole fruit  0.01             -          1                  0.01-0.18
    United         0.16            1-2          45-83         whole fruit  0.004            3          1                  0.01-0.04
    Kingdom        0.1-0.34        1            28            whole fruit  0.01             2          -                  0.02-0.04

    France         0.15-0.24       1            21-30         whole fruit  0.15             4          3                  0.21

                                                                                                                                           

    Table 2. (continued)

                                                                                                                                           

    Crop/          Rate of         No. of       Preharvest    Plant        Limit of         No. of     No. of residues    Residues above
    Country        application     treatments   interval      Part         determination    analyses   below limit of     limit of 
                   (kg a.i./ha)                 (days)        analysed     (mg/kg)                     determination      determination
                                                                                                                                           

    -Apple
    Germany        1.2             2            60            whole fruit  0.004            1          -                  0.1
                   2.0             1            132           whole fruit  0.005            1          -                  0
                   1.6-3.2g/tree1  74-118                     whole fruit  0.005            9          -                  0-0.08
                   1.5             1            133           whole fruit  0.009            1          1                  -
                   1.2             1-2          60-131        whole fruit  0.01             5          4                  0.02
                   3.2g/tree       1            132           whole fruit  0.01             1          -                  0.01
                   1.2g/tree       1            63-75         whole fruit  0.03             2          -                  0-0.09

    New Zealand    -               1            36            whole fruit  0.01             1          -                  0.01

    South          0.126-0.2       1-9          28-50         whole fruit  0.01             17         -                  0.01-0.3
      Africa

    -Citrus
    South          1.3-3.3         4            49-132        peel         0.002            -          1.2-2.7
    Africa         1.3-3.3         4            49-132        pulp         0.02             3          -
                                                              whole fruit                              0.3-0.7

    -Grapefruit
    South          14.85           1-2          168-211       peel         0.002            2          0.01-0.7
    Africa         14.85           1-2          168-211       pulp         0.02             2          -
                                                              whole fruit                              0.02-0.25

    -Lemons
    South          0.61-1.69       1-6          18-58         peel         0.01             14         -                  0.3-48
    Africa                                                    pulp         0.01             14         11                 0.01
                                                              whole fruit                                                 0.1-1.6

                                                                                                                                           

    Table 2. (continued)

                                                                                                                                           

    Crop/          Rate of         No. of       Preharvest    Plant        Limit of         No. of     No. of residues    Residues above
    Country        application     treatments   interval      Part         determination    analyses   below limit of     limit of 
                   (kg a.i./ha)                 (days)        analysed     (mg/kg)                     determination      determination
                                                                                                                                           

    -Lemons
    South          1.32            2            10-14         peel         0.01             4                             2.0-2.7
    Africa         1.32            2            10-14         pulp         0.01             4                             0.03-0.04
                   1.32            2            10-14         juice        0.01             8                             0.02-0.03
                                                              whole fruit                                                 0.7-0.93

    -Oranges
    Italy          1.9-3.8         6            99            peel         0.01             2                             5.3-11.0
                   0.76-3.8        5-6          99-122        pulp         0.02             4          1                  0.04-0.07
                   0.76            5            122           peel         0.02             2                             5.0-5.8
                                                              whole fruit                                                 1.35-2.8

    Morocco        2.4-3.2         1            60            peel         0.002            2          1                  0.002
                   2.4-3.2         1            60            pulp         0.002            2          2                  -
                   1.6-3.2         1            30            peel         0.006            3                             0.24-0.35
                   1.6-3.2         1            30            pulp         0.006            3          1                  0.01-0.02
                                                              whole fruit                                                 0.07-0.1


    South          1.85            2            14            peel         0.01             4                             1.3-3.5
    Africa         1.85            2            14            pulp         0.01             4                             0.05-0.2
                   1.85            2            14            juice        0.01             9                             0-03-0.05
                                                              whole fruit                                                 0.36-1.0

                   1.2             1            42            peel         0.02             1                             1.6
                   1.2             1            42            pulp         0.008            1          1                  
                                                              whole fruit                                                 0.4

                                                                                                                                           

    Table 2. (continued)

                                                                                                                                           

    Crop/          Rate of         No. of       Preharvest    Plant        Limit of         No. of     No. of residues    Residues above
    Country        application     treatments   interval      Part         determination    analyses   below limit of     limit of 
                   (kg a.i./ha)                 (days)        analysed     (mg/kg)                     determination      determination
                                                                                                                                           

    -Oranges
    United         0.89-3.56       3            60            peel         0.01             3                             5.3-17.0
    States                                                    pulp         0.02             3          3                  0.04-0.06
                                                              whole fruit                                                 1.35-4.3

                   2.27            1            57-218        peel         0.01             2          1                  0.2
                   2.27            1            57-218        pulp         0.01             2          2
                                                              whole fruit                                                 0.05

    -Pears
    United         0.16-0.96       1            45            whole fruit  0.01             4          2                  0.05-0.24
    Kingdom        0.16-0.96       1            28            whole fruit  0.02             3          -                  0.03-0.1

    South          0.18            5            49            whole fruit  0.01             1          1
    Africa

    Vegetables

    -Brussels sprouts
    United         0.21            1            21            green plant  0.01             1          1
    Kingdom        0.4-0.8         1            20-28         not stated1  0.02             8          -                  0.03-0.09

    -Savoy cabbage
    Federal        0.8             1            35-83         not stated   0.009            8          7                  0.02
    Republic       0.2             1            35-87         not stated   0.02             3          2                  0.02
    Germany

    -Summer Cabbage
    United         0.01-0.04       1            54            not stated   0.13             3          3
    Kingdom        g/plant

                                                                                                                                           

    Table 2. (continued)

                                                                                                                                           

    Crop/          Rate of         No. of       Preharvest    Plant        Limit of         No. of     No. of residues    Residues above
    Country        application     treatments   interval      Part         determination    analyses   below limit of     limit of 
                   (kg a.i./ha)                 (days)        analysed     (mg/kg)                     determination      determination
                                                                                                                                           

    -White Cabbage
    Federal        0.04-0.1 g/     1-2          84            not stated   0.004            3
    Republic       plant
    Germany        0.36-3.0        1            56-84         not stated   0.004            3          3
                   1.5-2.5         1            90            not stated   0.00             2          1                  0.01
                   0.36-3.0        1            42-123        not stated   0.01             8          7                  0.02
                   0.04-0.1 g/     1-2          63-123        not stated   0.01             3          2                  0.01
                   plant

    New            0.6             1            28            not stated   0.05             1          1
    Zealand

    Philippines    0.07-0.28g/ha   9            21            not stated   0.004            3          2                  0.06
                   0.45            7-11         7             not stated   0.005            3          -                  0.008-0.01

    United         0.6-1.2         1            21-28         not stated   0.01             3          2                  0.01
    Kingdom

    -Carrots
    Federal        3.2-4.0         1            88            not stated   0.004            2                             0.01
    Republic
    Germany

    United         1.12-2.24       1            23-115        not stated   0.01             5                             0.01-0.06
    Kingdom

                                                                                                                                           

    Table 2. (continued)

                                                                                                                                           

    Crop/          Rate of         No. of       Preharvest    Plant        Limit of         No. of     No. of residues    Residues above
    Country        application     treatments   interval      Part         determination    analyses   below limit of     limit of 
                   (kg a.i./ha)                 (days)        analysed     (mg/kg)                     determination      determination
                                                                                                                                           

    -Cauliflower
    Federal        0.1 g/plant     1            53-64         head         0.004            3          1                  0.007
    Republic       1.5-3.0         1            59            head         0.004            2          2
    Germany        0.8             1            35-70         head         0.006            9          9
                   0.016 g/plant   1            49            not stated   0.008            3          2                  0.04
                   0.48            1            35-63         not stated   0.02             2                             0.09-0.1
                   0.9             1            42            head         0.003            1                             0.008
                   0.2             1            35-60         head         0.03             2          2
                   0.36            1            56            head         0.06             1          1
                   0.36            1            16-55         not stated   0.06             2          1                  0.2
                   0.36            1            56            head         0.06             1          1
                   0.48            1            63            plant        0.06             1          1

    -Onions
    Federal        12-15 g/kg seed 1            133-142       onion        0.01             5          5
    Republic                                                  leaves       0.01             4          2                  0.02
    Germany                                                   peel         0.01             2          2

                   12-20 g/kg seed 1            129-159       onion        0.02             6          4                  0.02-0.03
                                                              leaves       0.04             1          1
                                                              peel         0.04             6          5                  0.02

                   0.12-0.18       1            115-161       onion        0.03             4          4
                                   1                          leaves       0.03             4          4

                   12-15 g/kg seed 1            122           onion        0.2              2          2
                                                              leaves       0.05             2          2
                                                              peel         0.09             2          1                  0.1

                                                                                                                                           

    Table 2. (continued)

                                                                                                                                           

    Crop/          Rate of         No. of       Preharvest    Plant          Limit of         No. of     No. of residues    Residues above
    Country        application     treatments   interval      Part           determination    analyses   below limit of     limit of 
                   (kg a.i./ha)                 (days)        analysed       (mg/kg)                     determination      determination
                                                                                                                                           

    United         10 g/kg seed    1            98            not stated     0.02             1                             0.04
    Kingdom

    -Peas
    Federal        0.36            I            11-21         pea            0.05             4          4
    Republic       0.36-1.6        1-2          14-30         pea            0.02             6          6
    Germany        0.36            2            14-24         pea            0.005            2          2
                   0.24            1            35            pea            0.001            1          1

    United         0.6             2            23            pea            0.009            4          4
    Kingdom        0.34-0.67       1            21            pea            0.01             4          3                  0.03
                   0.34            1            19            pea            0.05             1                             0.08

    -Potatoes
    Federal        0.36-0.48       1            35-28         whole          0.001            3                             0.001-0.004
    Republic       0.18-0.24       2            14            whole          0.002            2          2
    Germany        0.18            2            14            whole          0.005            4          4
                   0.48            1            35            whole          0.007            2          1                  0.009
                   0.24            2            13-14         peel           0.007            3          3
                   0.24            2            13-14         pulp           0.06             3          3
                   0.18            2            14            pulp           0.01             1          1

    Others

    -Coffee
    Brazil         0.4             1            6-35          green beans    0.01             4          4
    -Cotton
    Australia      0.9-1.8         5            57            seed surface   0.04             2          1                  0.1
                                                              seed interior  0.02             2          1                  0.1
                   0.9-1.8         5            57            fibre          0.5              2                             0.5-3.2

                                                                                                                                           

    Table 2. (continued)

                                                                                                                                           

    Crop/          Rate of         No. of       Preharvest   Plant          Limit of        No. of     No. of residues    Residues above
    Country        application     treatments   interval     Part           determination   analyses   below limit of     limit of 
                   (kg a.i./ha)                 (days)       analysed       (mg/kg)                    determination      determination
                                                                                                                                           

    -Cotton
    South          0.6-1.5         1-4          25           seed surface   0.03            6          6
    Africa                                                   seed interior                  5          5                  0.05

                   0.6-1.2         1-4          25           fibre          0.2             6          4                  0.29-1.44

    Turkey         0.6-0.8         1            48           fibre          0.02            2                             0.5-1.1
                                   1            48           seed           0.02            2          1                  0.1

    -Sugarbeet
    Federal        0.12-1.6        1            120-175      beet           0.005           8          8
     Republic      0.48 kg/100 kg  1            175-196      beet           0.05            4          4                  0.05
     Germany               seed
                   5.0             1            169          beet           0.05            1          1
                   0.24-0.48       1-3          35-42        beet           0.01            5          4                  0.01

    -Tobacco
    Canada         8.425           1            77-105       leaves         0.2             1          1

    Philippines    0.077-0.12      5            21           leaves         0.01            6                             9.4-5.5
                                                                                                                                           

    1    Not stated whether edible part was analysed.

    Table 3.  Triazophos Residues in Crops from Supervised Trials

                                                                                                                                             

                                                Application                 Residues (mg/kg) at intervals (days) after application
                                                                                                                                     
    Crop/Country      Plant    Year     No.    rate        formulation   10       20      30       50        80        100       >120
                      part                     kg a.i./ha
                                                                                                                                             

    Oranges

    South Africa      peel     1975     4      2           40 E.C.                                 2.91                1.5       1.2 (132)
                      pulp                                                                         n.d.                n.d.
                      peel              4      3.3-8.3     40 E.C.                                                     1.6
                      pulp                                                                                             n.d.

    Italy             peel     1980/    5      0.75        40 E.C.                        8.9      7.0       5.6                 5.8
                               81
                      pulp                                                                0.2      0.07      0.06                0.04
                      peel     1980     5      0.75        40 E.C.                        11.0     7.1       6.1                 5.0
                      pulp                                                                0.2      0.2       0.07                0.06
                      peel     1979     6      1.9         40 E.C.                                 7.6       9.5       5.3
                      pulp                                                                         0.07      0.02      n.d.
                      peel     1979     6      3.8         40 E.C.                                 15.0      8.7       11.0
                      pulp                                                                         0.06      0.05      0.07

    United States     peel     1973     1      2.27        40 E.C.                                 0.2
                      pulp                                                                         n.d.

    Morocco           peel     1972     1      3.2         40 E.C.                                 0.002
                      pulp                                                                         n.d.
                      peel     1972     1      2.4         40 E.C.                        0.35
                      pulp                                                                0.01
                      peel     1972     1      3.2         40 E.C.                        0.42
                      pulp                                                                0.02
                                                                                                                                             

    Table 3. (continued)

                                                                                                                                             

                                                Application                 Residues (mg/kg) at intervals (days) after application
                                                                                                                                     
    Crop/Country      Plant    Year     No.    rate        formulation   0        3       7        14        21        28        42
                      part                     kg a.i./ha
                                                                                                                                             

    Oranges
    South Africa      whole    1975     1      1.2         40 E.C.       0.6      0.4     0.5      0.6       0.4       0.3       0.6
                      peel     1978     2      1.85        40 E.C.       3.7      3.1     2.3      3.5
                      pulp                                               0.1      0.02    0.03     0.05
                      peel     1978     2      1.85        40 E.C.       4.6      4.9     2.5      1.7
                      pulp                                               0.2      0.04    0.1      0.2

    Lemons

    South Africa      peel     1979     3      1.22        40 E.C.                                                     2.4       2.1
                      pulp                                                                                             0.01      n.d.
                      peel     1980     4      2.88        40 E.C.                                           3.0                 2.0
                      pulp                                                                                   n.d.                n.d.
                      peel     1980     6      0.61        Bait                                              3.3       2.6
                      pulp                                                                                   0.01      0.01
                      peel     1979     3      4.32        30 W.P.                                                     2.9       2.4
                      pulp                                                                                             n.d.      n.d.
                      peel     1977     1      1.69        40 E.C.       1.4      1.3     1.1      0.5       0.6       0.3
                      pulp                                               n.d.     n.d.    n.d.     n.d.      n.d.      n.d.
                      peel     1978     2      1.32        40 E.C.       5.3      2.2     3.7      2.6
                      pulp                                               0.02     0.03    0.03     0.05

                                                                         0        25      40       60        90        120       >120
                                                                                                                                         
    Apples
    Argentina                  1980/81  2      2.7         30% W.P.      0.9      0.7     0.4      0.4       0.1
                               1980/81  2      2.4                       1.1      0.2     0.2      0.2       0.01

                                                                                                                                             

    Table 3. (continued)

                                                                                                                                             

                                                Application                 Residues (mg/kg) at intervals (days) after application
                                                                                                                                     
    Crop/Country      Plant    Year     No.    rate        formulation   0        25      40       60        90        120       >120
                      part                     kg a.i./ha
                                                                                                                                             

    Federal                    1975     1      3.0         40% E.C.               0.3     0.2      0.07                n.d.
    Republic                   1975     1      3.0         40% E.C.               0.3     0.3      0.09      0.07
    Germany                    1972     1      8g/tree     40% E.C.               1.1     0.5      0.2       0.08
                               1972     1      8g/tree     40% E.C.                       0.05     0.02      0.06      0.009
                               1977     2      1.2         40% E.C.               0.2     0.06     0.02

    South Africa               1979     3      0.2         30% W.P.      0.4      0.3     0.2
                               1979     6      0.2         30% W.P.      0.6      0.2     0.2
                               1979     3      0.2         40% E.C.      0.4      0.3     0.3
                               1981     4      0.2         30% W.P.      0.4      0.2     0.2      0.1
                               1980/81  4      0.2         30% W.P.      0.4      0.3     0.2      0.2
                               1980     6      0.27        30% W.P.      0.4      0.2     0.2
                               1981     5      0.18        30 W.P.       0.5      n.d.    n.d.     n.d.
                               1971     1      0.96        40 E.C.                        0.05
                               1971     1      0.64        40 E.C.                        0.24
                               1971     1      0.96        40 E.C.                0.11
                               1971     1      0.32        40 E.C.                0.03


                                                                         0        7       14
                                                                                                
    Bananas
    South Africa      peel              2      36g/1001    40 E.C.       1.6      0.8     0.6
                      pulp                                               0.08     0.03    0.07
                      whole                                              0.58     0.3     0.25
                      peel                     50g/1001    40 E.C.       1.9      1.0     0.1
                      pulp                                               0.09     0.1     0.09
                      whole                                              0.7      0.4     0.09

                                                                                                                                             

    Table 3. (continued)

                                                                                                                                             

                                                Application                 Residues (mg/kg) at intervals (days) after application
                                                                                                                                     
    Crop/Country      Plant    Year     No.    rate        formulation   0        7       14       21        28        35        84
                      part                     kg a.i./ha
                                                                                                                                             

    Brussels Sprouts
    United                     1974     1      0.8         40 E.C.                                 0.06
    Kingdom                    1971     1      0.4         40 E.C.                                 0.03
                               1974     1      0.8         40 E.C.                                 0.05
                               1974     1      0.4         40 E.C.                                           n.d.
                               1975     1      0.8         40 E.C.                                           0.09
                               1974     1      0.4         40 E.C.                                 0.04

    Savoy Cabbage
    Federal                    1974     1      0.8         40 E.C.                0.02    0.03     n.d.      n.d.      0.02
    Republic                   1974     1      0.8         40 E.C.                        n.d.     n.d.      n.d.      n.d.
    Germany                    1974     1      0.8         40 E.C.       0.4      n.d.    n.d.     n.d.      n.d.      n.d.
                               1974     1      0.2         40 E.C.       0.2      0.1     0.09     0.1       0.05      0.02

    Summer Cabbage
    United                     1971     1  0.01g/plant     5% Gran                                                     n.d.
    Kingdom

    White Cabbage
    Federal                    1973     1      0.36        40 E,C.       2.2              0.07               0.04      n.d.      n.d.
    Republic                   1973     1      0.36        40 E.C.       3.6              0.02     0.03      n.d.      0.05      n.d.
    Germany

    Philippines                1974     9      0.2g/l      40 E.C.       0.06     0.01    0.01     n.d.
                               1974     9      0.4g/l      40 E.C.       0.09     0.03    n.d.     n.d.
                               1974     9      0.6g/l      40 E.C.       1.4      0.1     n.d.     0.06

    New Zealand                1975     1      0.6         40 E.C.       4.0      0.17    0.06     n.d.

                                                                                                                                             

    Table 3. (continued)

                                                                                                                                             

                                                Application                 Residues (mg/kg) at intervals (days) after application
                                                                                                                                     
    Crop/Country      Plant    Year     No.    rate        formulation   0        7       14       21        28        35        84
                      part                     kg a.i./ha
                                                                                                                                             

    Cauliflower

    Federal                    1973     1      0.36        40 E.C.       0.3              n.d.               n.d.      n.d.
    Republic                   1973     1      0.36        40 E.C.                2.1     0.2      n.d.      n.d.      n.d.
    Germany                    1974     1      0.48        40 E.C.       0.4      0.4     0.2      0.2       0.1       0.09

                                                                         7        21      28       35        49        63        84
                                                                                                                                       
    Carrots
    Federal                    1972     1      4.0         40 E.C.                                           0.04      0.18      0.06
    Republic                   1972     1      3.2         40 E.C.                                           0.04      0.07      0.02
    Germany

    Peas
    United            pea      1974     1      0.34        40 E.C.                0.008
    Kingdom           pod                                                         0.5
                      pea      1972     1      0.67        40 E.C.                n.d.
                      pod                                                         0.04
                      pea      1972     2      0.6         40 E.C.                n.d.
                      pod                                                         0.4

                                                                                                                                             

    Table 3. (continued)

                                                                                                                                             

                                                Application                 Residues (mg/kg) at intervals (days) after application
                                                                                                                                     
    Crop/Country      Plant    Year     No.    rate        formulation   7        21      28       35        49        63        84
                      part                     kg a.i./ha
                                                                                                                                             

    Cottonseed

    Australia                  1970     5      0.9         40 E.C.                                 0.35      0.2
                               1970     5      0.9         40 E.C.                                 0.1       n.d.

    Cottonseed

    South Africa               1970     4      0.6         40 E.C.       0.2      0.05
                               1970     1      0.6         40 E.C.       0.05     n.d.
                               1970     3      0.6         40 E.C.       0.1      n.d.    n.d.
                               1970     3      1.2         40 E.C.       0.07     n.d.    n.d.

                                                                         0        3       7        14        21
                                                                                                                    
    Tobacco

    Philippines                1977     5      0.3         40 E.C.       27.6     13.3    12.7     8.2       6.9
                               1977     5      0.4         40 E.C.       25.2     13.8    8.6      11.4      7.5
                               1977     5      0.48        40 E.C.       27.5     15.5    18.7     16.1      9.4
                               1977     5      0.39        40 E.C.       36.2     8.5     15.7     6.4       8.3
                                                                                                                                             

    1    n.d. = not detected.
    

    Citrus

         One to six applications of triazophos to various species of
    citrus showed residue levels in the pulp of less than 0.1 mg/kg. Only
    in one out of 100 trials was a residue of 0.2 mg/kg determined. The
    fruit juices showed residue levels well below 0.05 mg/kg. The residue
    level in the peel was significantly higher, ranging up to 5.0 mg/kg.
    Studies in South Africa have shown that when citrus fruit is small and
    immature triazophos does penetrate into the pulp, but this residue is
    completely degraded within 30 days and before the fruit is harvested
    (see Table 4).

    Vegetables

         The vegetable samples analysed showed few or no residues above
    the limit of determination.

    Carrots

         In the course of investigations into the control of carrot fly,
    Suett (1975) showed that triazophos is readily taken up by carrots
    soon after spraying and that uptake continues during active growth.
    Following incorporation into the soil of 2 kg/ha of triazophos, the
    residue level in the carrots 6 mo. later ranged from 0.01 to 0.1
    mg/kg. The method and rate of application, carrot cultivar, soil type
    and age of carrots at harvest affected the uptake of residues. During
    storage, the residue level may increase due to loss of moisture from
    the carrot. The 6-8 percent of the carrot removed during peeling
    contains 75-90 percent of the total residues present. Cooking further
    reduces the concentration of residues,

    Potatoes

         None of the trials showed residue levels above 0.01 mg/kg.

    Sugarbeet

         No residues could be found in most of the trials. In some cases,
    0.01 to 0.05 mg/kg was determined.

    Cotton

         The highest residue level determined on cotton seed was 0.1
    mg/kg.

    Tobacco

         In six trials conducted in the Philippines, a maximal residue
    level of 9.4 mg/kg was determined following five applications. A
    further trial carried out in Canada showed residues of 0.2 mg/kg
    following a single application.

        Table 4.  Triazophos Residues in Oranges from Supervised Trials

                                                                                                  

    Spray                    Residue (mg/kg) at interval (days) after treatment
    concentration            O          11         21         32        41        50        57
                                                                                                  

    PULP

    0.025% a.i.              n.d.       1.4        0.3        n.d.      n.d.      n.d.      n.d.
                             n.d.       0.6        0.2        n.d.      n.d.      n.d.      n.d.
                             n.d.       0.2        0.08       n.d.      n.d.      n.d.      n.d.
                             n.d.       0.08       0.02       n.d.      n.d.      n.d.      n.d.
    0.04% a.i.               n.d.       0.08       0.12       n.d.      n.d.      n.d.      n.d.
                             n.d.       0.05       0.3        n.d.      n.d.      n.d.      n.d.
                             n.d.       0.012      0.08       n.d.      n.d.      n.d.      n.d.
                             n.d.       0.07       0.02       n.d.      n.d.      n.d.      n.d.
    0.08% a.i.               n.d.       0.01       0.01       n.d.      n.d.      n.d.      n.d.
                             n.d.       0.01       0.01       n.d.      n.d.      n.d.      0.01
                             n.d.       0.01       0.02       n.d.      n.d.      n.d.      0.01
                             n.d.       0.01       0.02       n.d.      n.d.      n.d.      0.01

    PEEL

    0.025% a.i.              1.2        2.1        1.3        1.5       1.2       1.9       1.7
    60 ml/100 l              1.1        1.7        1.7        1.7       1.6       1.1       1.5
                             0.81       1.5        0.9        1.2       1.2       1.1       0.9
                             0.83       1.5        1.2        2.4       1.5       1.0       1.0
    0.04% a.i.               1.5        3.0        2.7        3.2       2.9       1.7       2.1
    100 ml/100 l             1.7        2.5        2.2        3.8       1.8       1.7       2.9
                             1.4        2.8        2.4        3.2       2.1       1.7       2.5
                             1.8        2.7        4.1        3.3       3.8       2.6       2.7
    0.08% a.i,               2.6        4.3        3.8        3.7       3.3       3.9       3.8
    200 ml/100 l             3.9        7.3        6.5        3.2       3.3       4.3       6.3
                             4.0        5.8        5.3        3.4       3.6       6.1       4.9
                             3.7        5.5        5.0        4.9       3.7       5.4       5.1
                                                                                                  
    
    Coffee

         No residues could be determined in the green coffee beans.

    FATE OF RESIDUES

    In Animals

         No information was available on the distribution, excretion,
    storage or fate of triazophos in livestock. The 1982 Meeting evaluated
    information on its absorption, distribution, elimination and
    biotransformation in rats.

    In Plants

         The disappearance of residues from the plant surface is mainly
    caused by the evaporation of the unchanged active ingredient, if
    washing off by rain is excluded. This could be verified by trials with
    14C-labelled active ingredient on cotton, beans and rice (Thier 
    et al. 1971; Gorbach 1970; Thier et al. 1973; Bock et al. 1975).
    The residual half-life on cotton and rice was of the order of two to
    three weeks and, was four weeks on beans.

         Unchanged triazophos represents the only toxicologically
    significant residue at harvest and it can readily be determined by the
    usual means of residue analysis applicable to this substance (Thier 
    et al. 1979). At the time of harvest the degradation product 
    1-phenyl-3-hydroxy-l,2,4-triazole always represents a small fraction
    of the total residue. Only traces of the P=O analogue of triazophos,
    1-phenyl-3-(O,O-diethyl-phosphoryl) 1,2,4-triazole, are detectable on
    the plant surface, as confirmed by model trials with 14C-labelled
    triazophos in cotton, beans and rice (Gorbach 1970; Thier et al.
    1971; Thier et al. 1973). Thus, for example, on cotton plants four
    weeks after the final application in the greenhouse the residue of
    unchanged triazophos amounted to 4 percent of the applied
    radioactivity, 0.1 percent corresponded to 1-phenyl-3-hydroxy-1, 
    2,4-triazole and 0.04 percent to the P=O-analogue (Thier et al.
    1973). The latter was the only ChE inhibiting metabolite found. In
    routine residue samples of apples, grapes and oranges, ChE 
    inhibition was measured using a Technicon Auto-Analyser (Thier 
    et al. 1974). After deduction of the ChE inhibition 
    attributable to the intact active ingredient present, the 
    remaining ChE inhibition totalled in the region of only 0.1 ppb, 
    if attributed solely to the P=O analogue of triazophos.

         The uptake of triazophos and the translocation from the treated
    spot into other parts of the plant is different for the individual
    plant species.

    Cotton

         The persistence of triazophos on cotton plants was longer in the
    greenhouse than in the field. The substance penetrated rather quickly
    into deeper layers of the treated leaves but was not translocated in
    significant amounts into other parts of the plant. In the greenhouse,
    27 percent of the applied radioactivity was still present in the
    interior of the treated leaves after 4 weeks. The amount of intact
    triazophos in these leaves was 25 mg/kg. The P=O analogue of
    triazophos occurred only temporarily in the interior of treated
    leaves, the maximum residue level amounting to 0.5 mg/kg (Figure 1).

         Only slight residual radioactivity, or none at all, was
    detectable in the new shoots. Any radioactive residues found in the
    cotton fibre and seeds must have reached these parts by means of the
    biological transport of triazophos and its metabolites, since only the
    leaves were treated individually in the greenhouse trials and
    contamination of the bolls was avoided.

         It was also found that far less triazophos was absorbed via the
    roots from moist soil than from a hydroponic culture, the ratio being
    about 1 : 15 (Thier et al. 1973).

         Fifteen weeks after initial application, ca. 0.025 percent of the
    total radio activity applied directly to the plants was still present
    in the cotton fibre. The residues consisted of unchanged triazophos
    (0.02 mg/kg) 1-phenyl-3-hydroxy-l,2,4-triazole (0.01 mg/kg) and an
    unidentified compound (0.01 mg/kg). In the seeds, 0.3 mg/kg triazophos
    and 0.1 mg/kg 1-phenyl-3-hydroxy-l,2,4-triazole were found.

         The results of field applications in Spain demonstrated that only
    minor residues of triazophos and its metabolites are likely to be
    present in cotton fibre and seeds if the last application takes place
    before opening of the bolls (Table 3). The levels of the residues in
    the cotton fibre and seeds were ca. 0.1 mg/kg unchanged triazophos and
    0.1 mg/kg 1-phenyl-3-hydroxy-l,2,4-triazole; 0.1 mg/kg of an
    unidentified metabolite without ChE inhibiting properties, assumed to
    be a des-ethyl derivative of triazophos was also found. The identity
    of the intact active ingredient and the known metabolites was
    confirmed by comparison with control samples fortified with the
    labelled compounds (Thier et al. 1973).

    Beans

         In broad beans (Vicia faba) and dwarf beans (Phaseolus
    vulgaris), triazophos was absorbed by the plants, then metabolized
    and transported to the roots and new shoots (Figures 2 and 3). About
    40 percent of the active ingredient (ca. 20 mg/kg) applied evaporated
    within 20 to 30 days; 45 to 55 percent was degraded and remained in
    the plant. About 4 to 10 percent was retained as parent compound in
    and on the plant (Gorbach 1970).

    FIGURE 1

    FIGURE 2

    FIGURE 3

    Rice

         Transport into the rice grain occurs only to a very low extent
    (Figure 4). As in cotton, triazophos is less readily taken up from wet
    soil than from a hydroponic culture; the ratio is about 1 : 30.

         Greenhouse and field trials showed that only negligible residues
    of triazophos are likely to occur in rice grain, although
    contamination is possible during threshing. An unidentified metabolite
    found at low levels in the grain was not a ChE inhibitor in vitro.
    Rice straw and husks contained residues of triazophos and its
    metabolites; this should be considered when using the straw as fodder
    for livestock (Thier et al. 1971).

    In Soil

         The degradation capability of different soils was found by model
    trials with nine soil types, one of them tropical (from a Philippine
    rice field) and eight from different regions of the Federal Republic
    of Germany (Bock et al. 1975). Two of these were standard soils;
    they were used for trials for determination of degradation rates and
    formation of metabolites after different periods of time. In addition,
    14CO2-production from 14C-labelled active ingredient was
    investigated.

         The sandy soil showed a good mineralization capacity, as
    demonstrated by rapidly increasing CO2 production which rose to 18
    percent after 42 days (no figs. included) (Martens 1974). Eighteen
    days after application, less than 50 percent of the applied amount was
    still detectable as parent compound. After the eighth day, only one
    metabolite, representing 2-4 percent of the initial radioactivity, was
    found but could not be identified. In the less active sandy-loam soil
    the half-life was 87 days, with slower CO2 production (Martens 1974).

         Of the remaining seven soils, four degraded the compound more
    rapidly. After 12 weeks, only 3-8 percent of the initial radioactivity
    was recovered; the other three soils still contained 22-28% of the
    active ingredient. In nearly all of these seven soils, three unknown
    compounds and traces of hydroxy triazole (1 percent) occurred
    simultaneously as metabolites in individual amounts of 1-6 percent of
    the initial radioactivity.

         The leaching behaviour of triazophos was examined according to a
    regulation of the Biologische Bundesanstalt f. Land-und
    Forstwirtschaft. Contamination of the water table is not likely to
    occur as no triazophos was detected in the seepage water under drastic
    experimental conditions (Kelker & Thier 1973).

         In the field, a loamy and a sandy soil were sprayed individually
    with labelled triazophos at concentrations of 0.48 and 0.96 kg/ha.
    After 90 days, only slight radioactivity (1.8 to 4.3 percent of that
    applied) was detectable in the upper 10 cm of the treated plots, the
    radioactivity in loamy soil being slightly higher than that in the

    FIGURE 4

    sandy soil. The lower soil layers (10-20 cm), as well as the untreated
    neighbouring plots, exhibited little or no radioactivity (Bock et
    al. 1975).

         A loamy-sandy soil treated with different formulations of
    triazophos showed low residues in the upper layer (0-10 cm) and very
    low or no residues in deeper layers (10-30 cm) after 29 to 141 days
    (Kelker & Gorbach 1974).

         Triazophos was shown to have no effect, at concentrations up to
    100 mg/kg, on the rate of nitrogen mineralization in the soil, on the
    process of fixation of atmospheric nitrogen and on CO2 production in
    a loess soil with high organic matter content. Furthermore, it had no
    inhibiting effect on the isolated nitrogen-fixing enzyme nitrogenase
    from Azotobacter vinelandii cells (Neven et al. 1975). In
    addition, neither bacterial nor fungal growth nor oxygen uptake by the
    soils were inhibited (Tu 1980).

         In a study that measured the effects of 32 separate pesticides on
    the enzyme activity of an organic soil, it was found that triazophos
    inhibited dehydrogenase after one week and that the inhibition was
    more pronounced after two weeks of incubation, but was not as
    pronounced as that occurring merely as a result of heating the soil,
    which apparently releases soil organic matter. Triazophos inhibited
    the action of microflora involved in soil decomposition of OP
    compounds. Triazophos was the only pesticide of those tested that did
    not show some inhibition of urease at 10 mg/kg after one week of
    incubation. Following treatment with other pesticides, the urease
    activity returned to normal after two weeks. The author observed that
    the inhibition of soil enzymes is only transitory (Tu 1981).

    In Processing

         A study was made to determine the fate of triazophos residues in
    cottonseed subjected to normal processing. Triazophos was applied to
    cotton in Arizona when the balls were 80 percent mature. Three rates
    were applied (0.4, 0.6 and 1.1 kg/ha) by aircraft to separate plots
    and samples of cotton were collected 73 days later. The cotton was
    ginned and the cottonseed processed. The three fractions of the seed
    were analysed separately and the crude oil likewise after refining,
    bleaching and hydrogenating.

         The bulk of the residues was in the crude oil, which was
    significantly affected by the refining process. The concentration of
    residue was reduced by bleaching and completely eliminated by
    hydrogenation. No residues were carried over into soapstock. The
    amount of triazophos remaining in those fractions used for annual
    feeds (hulls and cottonseed meal) was apparently quite low.

         In extensive experiments conducted in Taiwan Province of China in
    1966 (Talekar et al. 1977), Chinese cabbage plants were sprayed at
    weekly intervals until harvest. Residues were monitored 0, 1, 3 and 7
    days after the last spraying. Triazophos persisted longer than all
    other organophosphorus and carbamate insecticides tested. It was found
    that the bulk of the residues were in the four outer leaf layers. A
    simple washing in cold water removed 50 percent of the triazophos
    residues from the leaves. There was a further decrease of about 50
    percent when the leaves were boiled in water for 20 min. (after
    allowing for the loss of about 60 percent of the water in the fresh
    leaves).

    RESIDUES IN FOOD IN COMMERCE OR AT CONSUMPTION

         There are no reports of triazophos residues being found in any
    published total diet studies. The Swedish government reported that
    triazophos was found only 14 times in routine analyses of 3 028
    samples of fruit and vegetables conducted in the 28 months ended 30
    April 1983. All of these samples were of imported commodities. The
    results are given in Table 5 (Sweden 1983).

    METHODS OF RESIDUE ANALYSIS

         A standard method for determination of triazophos in biological
    material was developed at Hoechst AG (Thier et al. 1979). The active
    ingredient is extracted with acetone from the sample material with
    homogenization in an Ultraturrax apparatus. The acetone extract is
    diluted with aqueous NaCl solution and extracted with methylene
    chloride. The combined methylene chloride extracts are dried in a
    sodium sulphate column, concentrated and the residue dissolved in
    ethyl acetate. If purification of the extracts of biological material
    is required, this is done by column chromatography on polystyrene gel
    with ethyl acetate as the mobile phase.

         The active ingredient is determined by gas chromatography using a
    flame-photometric detector. The recovery rate is 80-100 percent after
    addition of 0.01-1.0 mg/kg of active ingredient to the untreated
    control samples. The limit of detection is about 0.005 mg/kg.

    NATIONAL MAXIMUM RESIDUE LIMITS

         For existing maximum residue limits in countries where triazophos
    is registered see Table 1. Sweden has established an MRL for fruit and
    vegetables of 0.3 mg/kg.

    APPRAISAL

         This organophosphorus insecticide was evaluated in 1982, when a
    temporary ADI was estimated. The uses, residues resulting from such
    uses and the fate of residues were not considered at that time.

        Table 5.  Triazophos Residues found in Imported Food, Sweden1

                                                                                                  

    Food         Origin      No. of      No. of samples with residues within        Maximum
                             samples     given ranges (mg/kg)                       residue
                             analysed    <0.07   0.07-0.18   0.19-0.34   >0.34      (mg/kg)
                                                                                                  

    Apple        Sweden      286         286
                 Import      917         912                 3           2          2.0

    Mandarin     Import      292         291                 1                      0.27

    Orange       Import      622         618     3                       1          0.35

    Pepper       Import      206         205                             1          0.63
    (sweet)

    Tomato       Sweden      205         205
                 Import      500         497                 3                      0.22
                                                                                                  

    1    Total number of samples analysed: 8 654; Period: 81-01-01 to 83-04-30.
    

         Triazophos is a contact and stomach poison for insects and mites
    with a broad spectrum of effect against pests of many crops. It
    exhibits ovicidal action against summer eggs of mites and some insects
    and activity against free-living nematodes. The main fields of
    commercial use are cotton, sugarcane, maize, potatoes, vegetables,
    fruits (especially citrus), coffee and tobacco.

         Triazophos has been registered in many countries since 1970/71
    and the Meeting received comprehensive information on use patterns in
    18 countries where MRL's and withholding periods have been
    established. Authority to use triazophos extends to more than 30
    countries. The application rate ranges from 40 g to 2 kg/ha.

         The Meeting received reports of 318 residue trials together with
    corresponding analytical results. These revealed that, owing to the
    relatively low rate of application, the initial deposits are generally
    less than 2 mg/kg. The residual half-life under rainfree conditions
    ranges from two to four weeks, depending on the crop, with a
    considerable reduction following rain. This is because the major
    proportion of the deposit remains on the surface.

         Though triazophos penetrates plant surfaces, it is not
    translocated to any measurable extent. The cholinesterase-inhibiting
    residues at harvest consist almost exclusively of the parent compound,
    the P = 0 analogue being either absent or, if present, occurring at
    extremely low concentrations.

         No information was available on the fate of triazophos residues
    in livestock but, from studies carried out on rats, it appears likely
    that triazophos and its degradation products are rapidly excreted in
    urine and faeces and that little or none is retained in body tissues
    or fat.

         Triazophos has been shown not to leach from soil, not to affect
    biological processes in soil and to degrade at a moderately rapid rate
    in soils typical of several parts of the world. Triazophos is not
    taken up from soil by plants, although it may be absorbed from
    hydroponic solution.

         Information was available on the effect of processing and
    refining on residues in cottonseed and cottonseed oil, together with
    one study from Taiwan Province of China on Chinese cabbage, where it
    was shown that 50 percent of the triazophos residue is removed by
    water washing and 50 percent of the remainder is destroyed by cooking.
    Triazophos residues in cottonseed oil were destroyed when the oil was
    hydrogenated.

         Triazophos residues can be extracted from plant materials with
    acetone and, after transfer to methylene chloride, can be determined
    by gas chromatography, using a flamephotometric detector. The method
    gives food recoveries over the range 0.01-1.0 mg/kg with a limit of
    determination of 0.005 mg/kg.

         National MRLs have been established in a few countries.

    RECOMMENDATIONS

         The following MRL's are recommended for triazophos, determined
    and expressed as triazophos only. Metabolites are not included.


                                                                    

    Commodity               MRL           Preharvest interval (days)
                            (mg/kg)       on which MRL is based
                                                                    

    bananas                 2             7
    Brussel's sprouts       0.1           21
    cabbage                 0.1           21
    carrots                 0.1           30
    citrus fruit            2             60
    coffee                  0.05          14
    cotton seed             0.1           28
    cereal grains           0.05          40

    onions                  0.1           30
    pome:fruit              0.2           50
    peas                    0.1           14
    potatoes                0.05          14

    sugarbeet               0.05          45
                                                                    


    FURTHER WORK OR INFORMATION

    Desirable

                            Information on the fate of triazophos in
    livestock.

    REFERENCES - RESIDUES

    Bock, K.-D., Bock, R., Fischer, H., Gorbach, S. & Thier, W.G.
    1975                    Triazophos (active substance in the sales
                            product Hostathion(R)). Environmental impact,
                            degradation on/in plants, in soil and in
                            warmblooded animals. Environmental Quality and
                            Safety, Suppl. vol. III, p. 833-839. Georg
                            Thieme Publishers, Stuttgart.

    Gorbach, S. Degradation and distribution of triazophos in and on bean
    1970                    plants. Hoechst AG - Research report no. 
                            01-Z53-0174-70.

    Kelker, H. & Thier, W. Seepage behaviour of triazophos. Hoechst AG,
    1973                    Reports to the Biologische Bundesanstalt fuer
                            Land- und Forstwirtschaft according to
                            Memorandum No. 37.

    Kelker, W. & Gorbach, S. Trial for determination of triazophos
    1974                    degradation in field soil. Hoechst AG-Internal
                            report.

    Martens, R. The residual behaviour of triazophos in the soil.
    1974                    Institute for Soil Biology. Research Institute
                            for Agriculture., Braunschweig. (Unpublished)

    Neven, H., Vlassak, K. & Heremans, K.A.H. Invloed van ipuron,
    1975                    dinosebacetaat en triazophos op enkele
                            biologische processen in de bodem. Meded. Fac.
                            Land-bouwwetensch., 40(2,II) : 1221-30.

    Suett, D.L. Insecticide residues and carrot fly control. Agricultural
    1975                    Department Advisory Service, Quarterly Review
                            No. 19 125-138, Ministry of Agriculture,
                            Fisheries and Food, U.K.

    Sweden. Triazophos analyses in imported fruit and vegetables. Data
    1983                    submitted to FAO. 

    Talekar, N.S., Sun, L.T., Lee, E.M., Chen, J.S., Lee, T.M. & Lu, S.
    1977                    Residual behaviour of several insecticides on
                            Chinese Cabbage. J. Econ. Entomology, 70(6) :
                            689-692.

    Thier, W., Gorbach, S., Brommer, U. & Fischer, H. Distribution and
    1971                    metabolism of triazophos-3-14C and triazophos-
                            5-14C, respectively, with regard to the
                            triazole-component in and on rice under
                            different test conditions. Hoechst AG-Research
                            report no. 01-Z53-0193-71.

    Thier, W. Gorbach, S. & Fischer, H. Model experiments on the
    1973                    distribution and metabolism of triazophos in
                            and on cotton plants under different test
                            conditions. English translation of publication
                            in Z. Anal. Chem., 267 : 181-86.

    Thier, W., Schulze, E.F., Fischer, H. & Lohfink, G. In vitro
    1974                    examinations of residue samples originating
                            from field trials with triazophos (apples,
                            oranges, grapes) for determination of ChE-
                            inhibiting substances, using the 
                            Auto-Analyser. Hoechst AG-Research report 
                            no. 01-253-225-74.

    Thier, W., Losse, K. & Merz, H.D. Method of analysis for determination
    1979                    of HOE 02960 OI (triazophos) in biological
                            material. Hoechst AG-Internal report AL 17/79.

    Tu, C.M. Influence of pesticides and some of the oxidized analogues
    1980                    on microbial populations, nitrification and
                            respiration activities in soil. Bull. Environ.
                            Contam. Toxicol., 24 : 13-19.

    Tu, C.M. Effects of some pesticides on enzyme activities in an
    1981                    organic soil. Bull. Environ. Contam. Toxicol.,
                            27 : 109-114.


    See Also:
       Toxicological Abbreviations
       Triazophos (JMPR Evaluations 2002 Part II Toxicological)
       Triazophos (Pesticide residues in food: 1982 evaluations)
       Triazophos (Pesticide residues in food: 1986 evaluations Part II Toxicology)
       Triazophos (Pesticide residues in food: 1991 evaluations Part II Toxicology)
       Triazophos (Pesticide residues in food: 1993 evaluations Part II Toxicology)