SUBLETHAL INCIDENCE OF POLLUTANTS ON THE ENVIRONMENT - THE DDT EXAMPLE

By interacting with various reproduction events, pesticides have been involved in the rarefaction of some birds species, among which mainly predators. The role played by the DDT, regarded here as a model, is re viewed as an illustration of the organism's targets diversity. Multipl e effects of DDT on reproduction are tightly associated with complex h ormonal modifications. Eggshell fragilization is one of the best known consequences. Furthermore, biocumulative properties of DDT can explai n both many other ill-effects and the fact that prey birds act as priv ileged targets. This toxicokinetical aspect is illustrated here by the 14C-DDT kinetics in the japanese quail (coturnix coturnix japonica) t hat shows by the mean of autoradiography that the compound can be tran sfered from the maternal organism to the chick. At this time, the mole cular aspect of DDT action remains partly unclear but anyway the withd rawal of organochlorine insecticides eppears fully justified. Though t he risks of this kind of compounds are nowadays significantly decrease d, they should always be carefully considered in case of : (i) Handlin g for the purpose of toxicological studies (ii) Use as pesticides (iii ) Toxicological survey programs involving wild birds.