Sponsored jointly by FAO and WHO


    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




    The present Codex limit for orange, 0.2 mg/kg, was proposed by the
    Meeting in 1974,1/ and took into account the results of supervised
    trials derived from trunk pulverization. The Spanish delegation
    informed the Codex Committee on Pesticide Residues (CCPR) that the
    registered use of fenitrothion in Spain permits the pulverization of
    both leaves and fruits, which leads to higher residues in the fruits.
    Results of supervised trials reflecting the present use pattern and
    data on residues in citrus fruit moving in commerce were provided to
    the Meeting for evaluation. At its 14th session, the CCPR requested
    the Meeting to reconsider the definition of the residue, for which the
    original data were studied in 1969. The result of the evaluation is
    presented in this monograph addendum.


    The registered use rates are summarized in Table 1.

    Table 1   Registered Use Rates of Fenitrothion


    Country           Formulation     Rate                 Preharvest
                                      (kg a.i./ha or %)    interval

    Argentina         100 E.C.        0.04-0.06%
    Cyprus            50 E.C.         0.1-0.15/            7
    India             50 E.C.         0.5
    Iran              50 E.C.         1.0
    Paraguay          50 E.C.         0.08-0.15%
    Portugal          50 E.C.         0.1-0.15%
    Spain             50 E.C.)        0.1-0.15%            15
                      40 W.P.)        4.5
    Soviet Union      50 E.C.         0.006


    1/ See Annex 2 for FAO and WHO documentation.


    Sumithion 50 E.C. was applied in a 0.15 percent spray (equivalent to
    4.5 kg a.i./ha) to a commercial mandarin orchard at the beginning of
    colour change of fruits in Valencia, Spain. The parallel samples taken
    at various intervals were analysed with five different methods at five
    independent laboratories in Japan (Sumitomo), in the Netherlands (TNO)
    and in Spain. The results, including the variation of sampling and
    analyses, are summarized in Table 2. In the fruits analysed the
    average ratio of peel to pulp was 30:70 (Spain 1983).

    Another mandarin orchard was treated with 4.5 kg a.i./ha of Sumithion
    50 E.C. in 1981. Samples taken at 14, 21 and 28 days contained
    fenitrothion residues at levels of 1.1 mg/kg, 1.0 mg/kg and 0.9 mg/kg,
    respectively. The residue in the pulp was below the limit of

    Sumithion 50 E.G. was also applied in Japan (Sumitomo 1983)on mandarin
    orange at 4.5 kg a.i./ha. The average residue in whole fruit was 0.89
    mg/kg and 0.79 mg/kg 14 and 28 days after treatment. The average ratio
    of peel to pulp was 25:70.

    Orange trees were treated with two different formulations of
    fenitrothion at rates of 4.5 kg a.i./ha. The results of analyses were
    as follows:

    Days after          Folithion 50 E.C.        Sumithion 50 E.C.
    treatment           _____________________    _____________________
                        peel pulp whole fruit    peel pulp whole fruit

    14                  4.7   0.03     1.2       4.5  0.02      1.15

    28                  3    <0.02    0.9       3.3  0.03      0.96


    The major routes of degradation of fenitrothion are hydrolysis,
    demethylation and reduction to the amino compound. The formation of
    fenitrooxon is minor compared to products formed via hydrolysis. No
    fenitrooxon was detected in milk and meat of cattle kept on diets
    containing fenitrothion residues. The oxygen analogue may be formed in
    plants. However, it occurred only during the initial period at a small
    concentration (ca. 1 percent of total residue) (Miyamoto 1963) and its
    half-life was estimated to be only a few hours (Mollhoff 1968). Apple,
    rice, wheat and wheat products were tested for metabolites of
    fenitrothion but no oxon was reported.

        Table 2  Residues of Fenitrothion in Mandarins


    Before treatment                                  Residues (mg/kg) after treatment1
           Control               2 hours               7 days                 14 days                 21 days                  28 days
    peel   pulp    whole    peel   pulp    whole  peel   pulp   whole   peel    pulp   whole   peel    pulp     whole    peel   pulp    whole
                   fruit                   fruit                fruit                  fruit                    fruit                   fruit

    n.d.2  n.d.    n.d.     4.1    0.009   1.2    1.6    0.02   0.5     1.5     0.01   0.4     3.5     0.02     1.1      2.0    0.023   0.7
    n.d.   n.d.    n.d.     6.6    n.d.    1.8    6.6    n.d.   2.0     5.2     n.d.   1.6     5.0     n.d.     1.5      4.0    n.d.    1.2
    n.d.   n.d.    n.d.     7.9    n.d.    2.3    6.6    n.d.   1.9     6.4     n.d.   1.9     4.9     n.d.     1.6      4.8    n.d.    1.5
    n.d.   n.d.    n.d.     8.0    0.007   2.8    6.8    n.d.   2.1     4.8     n.d.   2.2     5.1     0.006    2.0      5.3    n.d.    2.1
    0.03   <0.005  <0.01    8.11   0.005   2.46   5.44   0.014  1.61    4.53    0.017  1.70    4.27    <0.005   1.64     5.10   0.005   1.84

                            6.94           2.11   5.41          1.62    4.48           1.56    4.55             1.57     4.24           1.47

    1 Treatment was 4.5 kg a.i./ha.

    2 n.d. = not detected.

    Fenitrothion residue was analysed in 181 orange, 138 lemon, 87
    grapefruit, 306 mandarin (satsumas) and clementine samples in Finland
    in 1982. Detectable residues were found in three lemon samples (0.32,
    0.63 and 0.78 mg/kg). In mandarin and clementine samples, the
    distributions of residue was:

    Residue (mg/kg)   <0.1   0.1-0.2   0.21-0.5   0.51-1.0   >1

    No. of samples       2       5          7         2        1

    The maximum residue measured was 1.1 mg/kg.


    The maximum residue level (MRL) for fenitrothion in orange was
    established by the 1974 Meeting. The mode of application of the
    compound has been changed since then.

    Results of supervised trials reflecting current good agriculture
    practice indicate that the residue in whole mandarins (Satsuma) ranges
    from 0.2 mg/kg to 2.1 mg/kg and in oranges it is about 1 mg/kg 28 days
    after application. The residue is mainly concentrated in the peel; the
    pulp contained residue up to 0.03 mg/kg only. The residue levels found
    in shipments imported from Spain to Finland support the results of
    supervised trials.

    Supervised trials carried out in different commodities indicate that
    the oxygen analogue occurs in plants only during the initial period in
    less than 1 percent of the total residue.


    Based on the limited information derived from supervised trials
    carried out in accordance with present good agricultural practice and
    the results of food surveys, the Meeting concluded that the existing
    MRL (0.2 mg/kg) of fenitrothion in orange has to be increased to 2
    mg/kg. The new limit is temporary, regardless of the status of the
    acceptable daily intake in man, and covers the residue in oranges and
    mandarins (Satsuma).

    All MRLs refer to the parent compound only. The new residue
    description does not alter the limits recommended.


    Required (by 1986)

    1. Information on current good agricultural practices.

    2. Results of supervised trials carried out on different varieties of
    citrus fruits according to present use recommendations.


    Finland.                  Fenitrothion residues in imparted citrus
    1983                      fruit.

    Miyamoto, J., Sato, Y.,   Studies on the mode of action of
    Vatoda, T., Fujinami, A.  organophosphorus compounds Part II.
    & Eudo, M.                Agric. Biol. Chem. (Tokyo),
    1968                      27: 669-76

    Mollhoff, E.              Beitrag zeer Frage der Ruckstande und ihrer
    1968                      Bestimmung in Pfdanzen nach tuwendung von
                              Praparaten der E605-und fapsitox-Reihe.
                              Pflanzenschutz Nachrichten, Bayer, 21: 331.

    Spain.                    Report on fenitrothion residue trials in
    1983                      mandarin and orange orchards. (Unpublished)

    Sumitomo                  Residues of Sumithion R in mandarin oranges
    1983                      sprayed in Japan. Report No. HR-30-0076.

    See Also:
       Toxicological Abbreviations
       Fenitrothion (EHC 133, 1992)
       Fenitrothion (HSG 65, 1991)
       Fenitrothion (ICSC)
       Fenitrothion (FAO/PL:1969/M/17/1)
       Fenitrothion (WHO Pesticide Residues Series 4)
       Fenitrothion (Pesticide residues in food: 1976 evaluations)
       Fenitrothion (Pesticide residues in food: 1977 evaluations)
       Fenitrothion (Pesticide residues in food: 1979 evaluations)
       Fenitrothion (Pesticide residues in food: 1982 evaluations)
       Fenitrothion (Pesticide residues in food: 1984 evaluations)
       Fenitrothion (Pesticide residues in food: 1986 evaluations Part II Toxicology)
       Fenitrothion (Pesticide residues in food: 1988 evaluations Part II Toxicology)
       Fenitrothion (JMPR Evaluations 2000 Part II Toxicological)