1967 EVALUATIONS OF SOME PESTICIDE RESIDUES IN FOOD
The content of this document is the result of the deliberations of the
Joint Meeting of the FAO Working Party of Experts and the WHO Expert
Committee on Pesticide Residues, which met in Rome, 4 - 11 December,
1967. (FAO/WHO, 1968)
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
WORLD HEALTH ORGANIZATION
This pesticide was evaluated by the 1965 Joint Meeting of the FAO
Committee on Pesticides in Agriculture and the WHO Expert Committee on
Pesticide Residues (FAO/WHO, 1965). Since the previous publication the
results of additional experimentation have become available and are
summarized and discussed in the following monograph addendum.
EVALUATION FOR TOLERANCES
RESIDUES RESULTING FROM SUPERVISED TRIALS
The sorption of carbon tetrachloride by cereals and cereal products is
less than that of some other fumigants used in the mixtures (ethylene
dichloride, ethylene dibromide). Increase of moisture content of wheat
from 9.0 to 18.5 per cent did not increase the uptake of carbon
tetrachloride. Even moderate decrease in particle size by grinding,
very markedly increased the uptake of the gas (Berck, 1965a).
Shelled walnuts, in 55-pound batches, were fumigated with 3 ml of a
carbon tetrachloride-acrylonitrile mixture (34 : 66 by volume).
Fumigation (3 hr) under reduced pressure, followed by storage for 30
days resulted in carbon tetrachloride residues (5.3 ppm) which were
lover than those (23.1 ppm) obtained by fumigation (48 hr) at
atmospheric pressure. An aeration for four hours after fumigation at
atmospheric pressure decreased the amount of carbon tetrachloride
found to 9.6 ppm. At a dosage of 6 ml at atmospheric pressure (48 hr)
33.7 ppm were found after 30 days storage (Berck, 1960).
RESIDUES IN FOOD MOVING IN COMMERCE
The Netherlands Government has analysed a number of imported cereals
and has found that nearly half of the samples investigated (276
samples from all over the world) contained a detectable amount of
carbon tetrachloride. In about 20 per cent of all samples the residue
range was 0.1 - 0.5 ppm, in 5 per cent the range was 0.5 -1 ppm, and
in 8 per cent the range was 1 - 5 ppm. Three per cent of the samples
investigated exceeded the 5 ppm level. The maximum residue found was
METHODS OF RESIDUE ANALYSIS
A polarographic method developed by Berck can be used for rapid
measurement of carbon tetrachloride in amounts as low as 10-5M
Berck (1965b) also described a gas chromatographic multi-detection
method for the determination of microgram amounts of 34 fumigant gases
including carbon tetrachloride.
An electron-capture gas chromatographic method for detecting carbon
tetrachloride residues in the ppb range has been described (Bielorai
and Alumot, 1966).
Country Tolerance, ppm Crop
India 5 ppm Cereals
Netherlands 0 ppm Grains
U.S.A. exempt Barley, corn,
RECOMMENDATIONS FOR TOLERANCES
Further work required before recommendations for acceptable daily
intakes and tolerances can be proposed. (See FAO/WHO, 1965)
1. Further investigation of the amount of the residual carbon
tetrachloride remaining in the food after treatment and the
effect on this of processing and cooking.
2. Long-term feeding studies should be carried out on two mammalian
REFERENCES PERTINENT TO EVALUATION FOR TOLERANCES
Berck, B. (1960) Retention of acrylonitrile and carbon tetrachloride
by shelled walnuts fumigated with acrylon. J. Agr. Food Chem. 8:
Berck, B. (1962) Polarographic determination of methyl bromide,
ethylene dibromide, acrylonitrile, chloropicrin and carbon
tetrachloride in air. J. Agr. Food Chem. 10 : 158-162.
Berck, B. (1965a) Sorption of ethylene dibromide, ethylene dichloride
and carbon tetrachloride by cereal products. J. Agr. Food Chem. 13 :
Berck, B. (1965b) Determination of fumigant gases by gas
chromatography. J. Agr. Food Chem. 13 : 373-377.
Bielorai, R., Alumot, E. (1966) Determination of residues of fumigant
mixture in cereal grain by electron capture gas chromatography.
J. Agr. Food Chem. 14: 622-625.
FAO/WHO. (1965) Evaluation of the hazards to consumers resulting from
the use of fumigants in the protection of food. FAO Mtg. Rept.
PL/1965/10/2; WHO/Food Add./28.65.