FAO/PL:1967/M/11/1
WHO/Food Add./68.30
1967 EVALUATIONS OF SOME PESTICIDE RESIDUES IN FOOD
THE MONOGRAPHS
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
Rome, 1968
ETHYLENE DICHLORIDE
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 available information pertinent to evaluations for tolerances has
been restudied and is summarized and discussed in the following
monograph addendum.
EVALUATION FOR TOLERANCES
USE PATTERN
Pre-harvest treatments
Ethylene dichloride, formulated with carbon tetrachloride, is
sometimes used on the trunks and lower branches of fruit trees to
control the peach tree borer. It is not used on any growing, edible
part of a tree. Therefore, no ethylene dichloride residues result in
foods from any known pre-harvest use.
Post-harvest treatments
A 3:1 ethylene dichloride-carbon tetrachloride mixture is commonly
used as a fumigant for grain, pulses, and animal feeds. It is applied
to these commodities while they are in bulk storage bins or under
gasproof covers. The mixture is used at the rate of 2 to 6.5 gal/1,000
bu (0.2 to 0.7 l/m3), depending on the product being treated and the
type of enclosure.
Other uses
It is occasionally used for fumigating household articles such as
clothing, rugs, upholstery, etc.
RESIDUES RESULTING FROM SUPERVISED TRIALS
Winteringham (1944a) found that sorption of ethylene dichloride by
flour reached equilibrium within 24 hours, but sorption by whole wheat
still continued after 1 week. In another study (1944b), he concluded
that the retention of ethylene dichloride by wheat is physical and
that there in no chemical decomposition of the fumigant within the
product.
Maximum residues on wheat obtained from fumigation with ethylene
dichloride (35 per cent) in combination with carbon tetrachloride (60
per cent) and ethylene dibromide (5 per cent) at the recommended
dosage (2 gal/1,000 bu) (0.2 l/m3) and at triple the dosage were 55
and 140 ppm of ethylene dichloride, respectively (Conroy, Walkden, and
Farrell, 1957).
Wheat treated with a mixture of carbon tetrachloride, ethylene
dichloride, and ethylene dibromide (60:35:5 per cent by volume) at the
normal dosage had 76 ppm of organic chloride in the wheat and 17, 22,
and 58 ppm of ethylene dichloride in the flour, shorts, and bran,
respectively (Munsey, 1957).
RESIDUES IN FOOD MOVING IN COMMERCE
Analyses conducted by The Netherlands during 1964-1965 period (CCPR,
1966) showed that 4 out of 227 lots of cereal sampled, or 1.6 per cent
of those imported, had ethylene dichloride present. The origin of the
cereals with ethylene dichloride residues and the amounts found were:
United States 5 ppm
Argentina 1.4 ppm
70 ppm
70 ppm
FATE OF RESIDUES
In storage and processing
After wheat containing 140 ppm of ethylene dichloride was cleaned and
tempered, the residue fell to 41 ppm. Wheat with 34.6 ppm of ethylene
dichloride had 17.8 ppm after cleaning and tempering, and residues in
the fractions after milling were 3 ppm in the flour, 3.5 ppm in the
shorts, 22.8 ppm in the bran, and 12.0 ppm in the germ (Conroy,
Walkden, and Farrell, 1957).
Five bins of wheat fumigated with a carbon tetrachloride-ethylene
dichloride mixture had 418 ppm of ethylene dichloride, 24 hours after
fumigation, 325 ppm after the first turning (transfer to another bin),
and 263 ppm after the third turning (Stenger and Mapes, 1957).
Ethylene dichloride was added to flour at 6.1 and 40 ppm, the flour
made into bread dough, and the dough then baked. The bread made from
the two batches had less than 2 ppm of ethylene dichloride. Oats with
61.6 ppm of ethylene dichloride had an average of 31.4 ppm after
cooking (1 min) or a loss of 49 per cent (Munsey, Mills, and Klein,
1957).
When ethylene dichloride at levels up to 1,000 ppm was added to grain
and was fed to cows, an average of less than 0.25 ppm was found in the
milk. There appeared to be no direct correlation between the amounts
of ethylene dichloride added to the grain and that found in the milk
(Sykes and Klein, 1957)
When 140 pounds (63.5 kg) of 85-per cent extracted wheat flour was
fumigated for 48 hours at 25°C with 300 g of ethylene dichloride (11.1
lb/ton), samples from the center of the bag had 1,030 ppm, 350 ppm,
and 46 ppm after airing 1 hour, 2 days, and 7 days, respectively (Pest
Infestation Laboratory, 1943).
METHODS OF RESIDUE ANALYSIS
Ethylene dichloride residues have been determined by the combined
methods of Ramsey (1957) which measures the carbon tetrachloride and
of Conroy, Munsey, and Ramsey (1957) which measures the total organic
halides. The amount of ethylene dichloride is calculated by
subtracting the amount of carbon tetrachloride from the total
inorganic halides. The sensitivity is 0.5 ppm.
An electron-capture gas chromatographic method for detecting certain
chlorinated residues in the ppb range has been described by Bielorai
and Alumot (1966). This method may be adapted for ethylene dichloride
residue analysis.
NATIONAL TOLERANCES
Country Tolerances Crop
Canada Exempt Grain
United States Exempt1/ Grain
1/According to U.S. Food and Drug laws, ethylene dichloride is
exempt from requirement of a residue tolerance because when used as
a fumigant for grain under currently prevailing practices it does not
appear to involve any hazard to public health.
RECOMMENDATIONS FOR TOLERANCES
Cereals fumigated with ethylene dichloride according to good
agricultural practices may contain high levels of the fumigant for a
relatively long time. Aeration, aging, and processing will remove most
of the ethylene dichloride but very small amounts may persist in the
food. Since no reaction products or metabolites of ethylene dichloride
have been found in grain, (IUPAC, 1967), the concern is over the
amount of the ethylene dichloride per se present in the food when it
reaches the consumer. No suitable analytical method is available for
the specific determination of this fumigant. Furthermore no acceptable
daily intake (ADI) could be estimated at this time with the available
toxicological data.
Under the above conditions, no tolerances were recommended for
ethylene dichloride.
FURTHER WORK
Further work required before acceptable daily intakes and tolerances
can be recommended
In addition to that specified in the previous publication (FAO/WHO,
1965) further data is required on:
Extent of use as a fumigant for raw and processed foods.
Residue levels in various food resulting from good agricultural
practices and the effects of aerating, aging, processing, and cooking
in reducing residues of ethylene dichloride.
Development of a specific method for detecting ethylene dichloride
with a sensitivity of about .001 ppm.
Residue levels of ethylene dichloride in various types of food while
in trade channels.
REFERENCES PERTINENT TO EVALUATION FOR TOLERANCES
Bielorai, R. and Alumot, E. (1966) Determination of residues of
fumigant mixture in cereal grain by electron-capture gas
chromatography. J. Agric. Fd. Chem., 14(6) : 622-625.
CCPR. (1966) Codex Committee on Pesticide Residues. Residues of
insecticides in cereals, imported in the Netherlands, 1964/65, Second
Report. Paper prepared by the Ministry of Social Affairs and Public
Health, Ministry of Agriculture. CCPR 66-17.
Conroy, H.W., Munsey, V.E., and Ramsey, L.L. (1957) Residues foods and
foods resulting from fumigation of grains with the commoner liquid
formulations of carbon disulfide, carbon tetrachloride, ethylene
dichloride, and ethylene dibromide. 2. Ethanolamine-sodium reduction
procedure. J. Ass. Off. Agric. Chem., 40 (1) 9 185-189.
Conroy, H.W., Walkden, H.H., and Farrell, E. (1957) The fumigation,
milling, and sampling of wheat and its milled products. B. Manhattan
studies. J. Ass. Off. Agric. Chem., 40 (1) : 166-168, 192-195.
FAO/WHO. (1965) Evaluation of the hazards to consumers resulting from
the use of fumigants in the protection of food. FAO Mtg. Rept. No.
PL/1965/10/2; WHO/Food Add./28.65.
IUPAC. (1967) International Union of Pure and Applied Chemistry.
Proceedings of the Commission on Terminal Residues and the Commission
on Residue Analysis. Vienna, August, 1967.
Munsey, V.E. (1957) The fumigation, milling and sampling of wheat and
its milled products. J. Ass. Off. Agric. Chem., 40(1) : 165, 192.
Munsey, V.E., Mills, P.A., and Klein A.K. (1957) Effects of cooking on
fumigated residues. J. Ass. Off. Agric. Chem., 40(1) : 201-202.
Pest Infestation Laboratory. (1943) Pest Infestation Research Report :
87. Slough, England.
Ramsay, L.L. (1957) Residues in foods and feeds resulting from
fumigation of grains with the commoner liquid formulations of carbon
disulfide, carbon tetrachloride, ethylene dichloride, and ethylene
dibromide. B. Colorimetric determination of carbon tetrachloride in
fumigated cereal products. J. Ass. Off. Agric. Chem., 40(1) : 175-180.
Stenger, V.A. and Mapes, D.A. (1957) Effect of baking on ethylene
dibromide and total bromide residues. J. Ass. Off. Agric. Chem.,
40(1): 196-200.
Sykes, J.F. and Klein, A.K. (1957) Chloro-organic residues in milk of
cows orally administered ethylene dichloride. J. Ass. Off. Agric.
Chem., 40(1) : 203-206.
Winteringham, F.P.W. (1944a) The sorption of ethylene dichloride by
wheat products. J. Soc. Chem. Ind., 63 : 144-150.
Winteringham, F.P.W. (1944b) The sorption of ethylene dichloride by
wheat products. J. Soc. Chem. Ind., 63 : 359-363.