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 FENITROTHION RESIDUES Explanation 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. USE PATTERN 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 (days) 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. RESIDUES RESULTING FROM SUPERVISED TRIALS 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 determination. 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 FATE OF RESIDUES 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. RESIDUES IN FOOD IN COMMERCE OR AT CONSUMPTION 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. APPRAISAL 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. RECOMMENDATIONS 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. FURTHER WORK OR INFORMATION 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. REFERENCES- RESIDUES 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. (Unpublished)
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)