FAO/PL:1968/M/9/1
WHO/FOOD ADD./69.35
1968 EVALUATIONS OF SOME PESTICIDE RESIDUES IN FOOD
THE MONOGRAPHS
Issued jointly by FAO and WHO
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 Geneva, 9-16 December,
1968.
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
WORLD HEALTH ORGANIZATION
Geneva, 1969
DDT
Since the previous evaluation (FAO/WHO, 1968) additional data have
become available and are summarized and discussed in the following
monograph addendum.
RESIDUES IN FOOD AND THEIR EVALUATION
Background
At the Second Session of the Codex Committee on Pesticide Residues,
the delegation of Australia proposed that a practical residue limit
should be established for DDT residues in eggs and suggested a limit
of 0.5 ppm DDT plus metabolites (CCPR, 1967). The 1967 Joint Meeting
did not consider the proposal because of the absence of relevant data.
At the Third Session of the Codex Committee on Pesticide Residues it
was agreed (CCPR, 1968) that Australia would prepare a submission for
consideration by the 1968 Joint Meeting (Australia, 1968).
Residues resulting from supervised trials
The literature on residues in poultry fat and eggs resulting from the
controlled use of DDT on and around poultry and from known amounts of
DDT in poultry feeds is most extensive. Bearsé (1966) has made a
comprehensive review of the published literature on pesticide residues
in poultry products.
The deposition of DDT into chicken eggs from a feed source was
demonstrated by Rubin et al. (1947). They showed that residues in the
egg increased as dietary levels of DDT increased.
The presence of residues in eggs, and poultry tissues resulting from
the inclusion of alfalfa containing DDT in the ration was reported by
Draper et al. (1950 and 1952) and Bryson et al. (1950). Liska et al.
(1964) showed that the feeding of hens on a ration containing 0.1 ppm
DDT for 30 days resulted in residues in the egg yolk below 0.1 ppm. A
ration containing 0.5 ppm DDT gave rise to residues of 1.3 ppm DDT in
egg yolk.
Bryson et al. (1950) carried out extensive investigations into the
effect on eggs from feeding DDT-contaminated alfalfa meal in the mash
of hens. The amount of DDT in the eggs was correlated with the DDT
intake. Up to 5 ppm DDT in eggs arose from the feeding of a mash
containing 15 per cent of alfalfa from fields treated with DDT.
Stadelman et al. (1965) observed that feeding DDT to laying hens by
capsule at the rate of 0.1 to 0.15 ppm in the diet for 14 days
resulted in residues in egg yolk. Samples analysed five weeks after
the feeding period ended contained no residues. Feeding 10-15 ppm of
DDT for five days resulted in significant residues in eggs which were
extremely persistent. DDT had disappeared 26 weeks after feeding
stopped but DDE, the degradation product, persisted beyond that time.
Of 537 samples of egg pulp examined in Australia during 1966/67, 40
per cent were found to contain traces of DDT metabolites, most being
less than 0.25 ppm. Of all the samples examined, only one per cent
contained residues in excess of 0.5 ppm but nine per cent of samples
ranged between 0.26 and 0.5 ppm. During 1968 the method of making the
survey was revised and samples were taken from localities where the
most significant residues had been found in previous surveys. Of 944
samples examined, 47 per cent contained detectable quantities of DDT
and metabolites; 19 per cent contained less than 0.25 ppm, 15 per
cent between 0.26 ppm and 0.5 ppm and 12 per cent between 0.51 and
1.0 ppm. Only 1.4 per cent of the subjective samples contained DDT
and metabolites totalling more than 1.0 ppm. In this survey all
detectable residues were recorded and added to give the total values
quoted (Australia, 1968).
Wesley et al. (1966) carried out an investigation to determine the
effect of management practices on the depletion of DDT residues in
eggs of commercial laying hens following a measured exposure to the
insecticide. Following the administration of DDT the residual DDT in
the egg yolk declined from a peak of 4.5 ppm to only 0.38 ppm in 17
weeks.
Cummings et al. (1966) conducted a low-level feeding experiment with
laying hens using a mixture of pesticide chemicals. Sixty hens were
carried for 20 weeks in a study designed to show the residue levels in
eggs from hens on feed containing 0.05, 0.15 or 0.45 ppm of lindane,
heptachlor epoxide, dieldrin, endrin, and DDT in combination. The DDT
was a 70/30 synthetic mixture of p,p'-DDT and o,p'-DDT. The basal diet
had less than 0.01 ppm of each of the pesticides (and DDE). No report
was made on the amount of DDD or o,p'DDT that built up. The p,p'-DDT
and DDE residues at the end of 96 days feeding are shown in Table I.
The p,p'-DDT appeared to have nearly plateaued at this time but DDE
continued to increase at a steady rate.
TABLE I. RESIDUES IN WHOLE EGGS
ppm
Total pp'DDT
Feeding level p,p'-DDT DDE and DDE
0.05 0.06 0.03 0.09
0.15 0.11 0.04 0.15
0.45 0.28 0.09 0.37
Ninety-seven per cent of the DDT was in the yolk and three per cent
in the white.
Evidence of residues in food moving in commerce or at consumption
The United States Food and Drug Administration report that 66.4 per
cent of 2444 samples of domestic shell eggs and 26 per cent of 116
samples of imported shell eggs, examined in the years 1964 through
1967, contained DDT or its metabolites. Though the average level of
these residues was 0.08 ppm and 0.02 ppm respectively, a significant
proportion of the samples contained residues in excess of 0.1 ppm. By
far the largest proportion of the residue occurred in the form of DDE.
Of 537 samples of egg pulp examined in Australia during 1966-67, 40
per cent were found to contain traces of DDT metabolites, most being
less than 0.25 ppm. Of all the samples examined, only one per cent
contained residues in excess of 0.5 ppm but nine per cent of samples
ranged between 0.26 and 0.5 ppm.
The data appear to indicate that residues in feed below 0.5 ppm DDT
would result in eggs with total residues of DDT, DDE and TDE below 0.5
ppm.
RECOMMENDATIONS FOR TOLERANCES AND PRACTICAL RESIDUE LIMITS
Appraisal
Even in countries such as the United States of America, Canada and
Australia where the treatment of poultry with DDT is not permitted and
where DDT is not used for the treatment of cereal grains and animal
feeds, it has been shown that significant levels of DDT residues occur
in eggs. The available information indicates that DDT cannot be
eliminated from the environment or from animal feedstuffs. The
presence of small quantities of DDT metabolites in egg yolk arises as
a consequence of the protection of people, food crops and animals from
insect attack.
The Codex Committee on Cocoa and Chocolate also requested a tolerance
for DDT in cocoa and cocoa products, but did not provide sufficient
data for the meeting to arrive at a decision.
In respect to the practical residue limits for DDT in whole milk and
milk products contained in the report and monographs prepared at the
1967 Joint Meeting (FAO/WHO, 1968a and b), the meeting agreed that
these recommendations were in error. The practical residue limits for
milk and milk products (on a fat basis) should have been 0.05 ppm and
1.25 ppm, respectively.
Attention should also be drawn to the omission in the 1967 report and
monographs (FAO/WHO, 1968a and b) of a previously recommended
temporary tolerance for nuts, on a shell-free basis (FAO/WHO, 1967).
Recommendations
In addition to the previously recommended temporary tolerances and
practical residue limits (as corrected) to be in effect until 1970:
Temporary tolerances
Apples, pears, peaches, apricots,
small fruit (except strawberries),
vegetables (except root vegetables),
meat, fish or poultry (on a fat
basis) 7.0 ppm
Nuts (shelled) 1.0 ppm
Strawberries, root vegetables 1.0 ppm
Cherries, plums, citrus fruit,
tropical fruit 3.5 ppm
Practical residue limits
Whole milk 0.05 ppm
Milk products (on a fat basis) 1.25 ppm
The meeting also recommends the following practical residue limits
to be in effect until 1970:
Eggs (on a shell-free basis) 0.5 ppm
The above temporary tolerances and practical residue limits are to
apply to raw agricultural products moving in commerce unless otherwise
indicated. In the case of fruits and vegetables the tolerances should
be applied as soon as practicable after harvest and in any event prior
to actual retail to the public. In the case of commodities entering
international trade, the tolerances should be applied by the importing
country at the point of entry or as soon as practicable thereafter.
REFERENCES
Australia. (1968) Submission to 1968 Joint Meeting of the FAO Working
Party of Experts and the WHO Expert Committee on Pesticide Residues.
Prepared by the Australian Delegation to the Codex Committee on
Pesticide Residues
Bearsé, G. E. (1966) Pesticide Residues and Poultry Products: USA
Legislation and Pertinent Research. Proceedings of the International
Poultry Conference, 194-2-6 (1966)
Bryson, M. J., Draper, C. I., Harris, J. R., Biddulph, C., Greenwood,
D. A., Harris, L. E., Binns, W., Miner, M. L. and Madsen, L. I. (1950)
DDT in eggs and tissues of chickens fed varying levels of DDT.
Advances in Chem. Series, 1: 232
CCPR. (1967) Report of Second Session of the Codex Committee on
Pesticide Residues; (ALINORM 68/24)
CCPR. (1968) Report of Third Session of the Codex Committee on
Pesticide Residues; (ALINORM 69/24)
Cummings, J. G., Zee, K. T., Turner, V., Quinn, F., Cook, R. E. (1966)
Residues in eggs from low level feeding of five chlorinated
hydrocarbon insecticides in hens. J. Offic. Anal. Chem., 49: 354-364
Draper, C. I., Buddulph C., Greenwood, D. A., Harris, J. R., Binns,
W. and Miner, M. L. (1950) Concentration of DDT in tissues in chickens
fed varying levels of DDT in the diet. Poultry Sci., 29: 756
Draper, C. I., Harris, J. R., Greenwood, D. A., Biddulph, C., Harris,
I. E., Mangelson, F., Binns, W. and Miner, M. L. (1952) The transfer
of DDT from the feed to eggs and body tissues of White Leghorn hens.
Poultry Sci., 31: 388
FAO/WHO. (1967) Evaluation of some pesticide residues in food.
(FAO/PL:CP/15; WHO/Food Add./67.32)
FAO/WHO. (1968a) Report of the 1967 Joint Meeting of the FAO Working
Party of Experts and the WHO Expert Committee on Pesticide Residues
(FAO/PL:1967/M/11; Wld Hlth Org. techn. Rep. Ser., 391)
FAO/WHO. (1968b) 1967 evaluations of some pesticide residues in food
(FAO/PL:1967/M/11/1; WHO/Food Add./68.30)
Liska, B. J., Langlois, B. E., Mostert, G. C. and Stadelman, W. J.
(1964) Residues in eggs and tissues of chickens on rations containing
low levels of DDT. Poultry Sci., 43: 982
Rubin, M., Bird, H. R., Green, N. and Carter, R. H. (1947) Toxicity of
DDT to laying hens. Poultry Sci., 26: 410
Stadelman, J. W., Liska, B. J., Langlois, B. E., Mostert, G. C. and
Stemp, A. R. (1965) Persistence of chlorinated hydrocarbon insecticide
residues in chicken tissues and eggs. Poultry Sci., 44: 435
Wesley, R. L., Stemp, A. R., Liska, B. J. and Stadelman, W. J. (1966)
Depletion of DDT from commercial layers. Poultry Sci., 45 (In press)