Kinetics, dose-response, excretion, and toxicity of methylmercury in free-living Cory's shearwater chicks.
Methylmercury (MHg) kinetics, dose-response, excretion, and toxicity were experimentally evaluated and compared between small (one to two weeks old) and large (six to seven weeks old), free-living Cory's shearwater chicks. The half-time for the terminal elimination phase of MHg in blood (5.7 d) and the average percentage of ingested MHg deposited in the blood volume (12%) were independent of the age at exposure. Therefore, these data were employed to derive a relationship between steady-state blood concentrations and dietary intake of MHg in bird chicks. Plumage:blood ratios were independent of dose and could be used as partition coefficients. Dose-response relationships in plumage and blood were linear over the wide range of exposures employed. Blood dose-responses of MHg in small and large chicks were similar. Excretion percentages into the final plumage varied between 42 and 60% of intake. The body condition of experimental chicks did not indicate sublethal toxicity of the doses administered; hence, the exposure levels provide maximum avian no-observed-adverse-effect levels for external symptoms in wild seabird chicks.
Monteiro
L R
LR
Department of Oceanography and Fisheries, University of the Azores, Horta, Portugal.
Furness
R W
RW
D000284:Administration, Oral; D000818:Animals; D000831:Animals, Newborn; D001717:Birds; D004305:Dose-Response Relationship, Drug; D005241:Feathers / Q000737:chemistry; D005260:Female; D007700:Kinetics; D008297:Male; D008767:Methylmercury Compounds / Q000493:pharmacokinetics / Q000633:toxicity*; D014018:Tissue Distribution
D008767:Methylmercury Compounds