PESTICIDE RESIDUES IN FOOD - 1983
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
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.
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
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
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.
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 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
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.
Finland. Fenitrothion residues in imparted citrus
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.