Further review of certain persistent organochlorine pesticides used in Great Britain.

  • Great Britain. Advisory Committee on Pesticides and Other Toxic Chemicals
Date:
1969
Catalogue details

Licence: Public Domain Mark

Credit: Further review of certain persistent organochlorine pesticides used in Great Britain. Source: Wellcome Collection.

    18/156 (page 12)
    EFFECTS ON MAMMALS 53. In British wild mammals, residues of DDT and its metabolites have been found in five major taxonomic groups, amongst which were herbivores, insectivores, omnivores, and carnivores, living in terrestrial, fresh-water, and marine environments [Appendix V (vii)]. There is insufficient information to allow any correlation to be drawn between residue levels found in mammals and death from DDT poisoning. Most of the residues are relatively low and it seems unlikely that British wild mammals are exposed to any risk from acute poisoning by DDT. Possible exceptions are the bats which are known to be particularly sensitive to DDT and for which the lethal dose is as low as 20 mg/kg in some species. 54. Many workers agree that the effects of repeated doses of DDT can be cumulative. Nevertheless, some excretion and detoxication of the compound does occur and experiments with rats have shown that when given in fractions over a period, a much larger total amount is required to produce the same effect as a single acute dose. Experiments with very large doses of DDT fed daily for upwards of three weeks have been shown to affect the gait of rats, but so far there is no evidence of effects on other behavioural functions. Such occurrences have not been seen in wild mammals in Great Britain. SUMMARY OF SIDE EFFECTS OF DDT 55. A study of the above data leads us to conclude that acute poisoning of birds by DDT has occurred only in local areas of Great Britain. However, there is some evidence that DDT may produce non-lethal effects on birds (paragraph 52). Fish are very sensitive to DDT at low concentrations, but there is little evidence of harm of this kind in Great Britain. DDT can have indirect ecological effects on arthropod populations; thus, pest mites in orchards benefit if the more sensitive parasites and predators are killed by this insecticide. III. RESIDUES IN FOOD (a) INTRODUCTION 56. Information on the occurrence and levels of pesticide residues in foodstuffs is obtained, in the first instance, from trials undertaken by Industry. This and subsequent data from the early commercial development of a chemical are always required by the Pesticides Safety Precautions Scheme. Our main information, however, on the occurrence of residues in foodstuffs has been obtained from the studies initiated by our Scientific Subcommittee’s Panel on Residues of Pesticides in Foodstuffs, set up for this purpose in 1961. The studies included selective surveys of residues in specific foodstuffs and in 1966 a whole- diet survey was initiated. In 1966-68, Public Analysts carried out a co-ordinated study of residues in foodstuffs on behalf of the County, Municipal, and District Councils Associations and some data from this investigation were made available to us. Certain-manufacturers of pesticides have also surveyed the occurrence of certain residues in the diet and some of the data have been published.