Dicofol residues in eggs and carcasses of captive American kestrels.

American kestrels (Falco sparverius) were fed diets containing 0 (control), 1, 3, 10, and 30 μg/g (wet wt) of Kelthane®. Residues of dicofol and its metabolites were then analyzed in the eggs and carcasses of females. Significant differences occurred among treatments for residues of both p,p′-dicofol and p,p′-dechlorodicofol (DCD) in both eggs and carcasses and for p,p′-dicholorbenzophenone (DCBP) in eggs. Residue concentrations increased with increasing treatment exposure. Residues of p,p′-dicofol, p,p′-DCD, and p,p′-DCBP in eggs were significantly correlated with eggshell quality parameters. Significant correlations also occurred among contaminants in eggs and for individual contaminants between eggs and carcasses. The lowest-observed-dietary-effect concentration for eggshell thinning was 3 μg/g, whereas 1 μg/g may be considered to be near a no-observable-adverse-effect concentration. Concentrations of dicofol in potential prey items and eggs of wild birds generally have been lower than dietary-effect concentrations or concentrations in tissues or eggs associated with eggshell thinning and reduced reproductive success.