Organochlorine pesticide residues in Florida birds of prey, 1969-76.

Chlorinated hydrocarbon pesticide residues, especially DDT and its metabolites, were determined in 71 individuals of 14 species of predatory birds obtained in Florida between 1969 and 1976. Of the 71 birds, 68 contained p,p'-DDE or another DDT metabolite; 34 contained dieldrin. DDE was found in 93 percent of the 57 adipose tissue samples, all the 9 brain samples, and 89 percent of the 62 uropygial gland samples. Of the 65 birds taken since 1972, 61 contained DDE in at least one of these three tissues. The annual average of sigmaDDT in adipose tissue and uropygial gland over the 6-year span was approximately 5 ppm wet weight. From 1973 to 1976, no significant increase or decrease in pesticide burdens was detected. Some birds had no DDE whereas others contained up to 76 ppm sigmaDDT. None of the data suggest that any of the birds of prey had died of DDT or DDT metabolite poisoning.