Contaminant Concentrations in Manatees in Florida

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Abstract
The status of the endangered manatee (T. manatus) in relation to organochlorine pesticides, polychlorinated biphenyls, Hg, Pb, Cd, Cu, Fe and Se was investigated in Florida from 1977-1981. Concentrations of organochlorines in blubber, Hg in muscle and liver, Pd in liver, and Pb and Cd in kidneys did not indicate high exposure to these contaminants. Only Cd in kidneys showed a positive correlation with relative age. No significant relationship existed between Fe and Cu in liver; Se concentrations in liver were low. Cu concentrations in livers of these aquatic herbivores were significantly elevated in areas of high herbicidal Cu usage after adjustment for significant age-related effects; upper values of 1200 ppm dry weight exceeded all previously reported concentrations in livers of any species of wild mammals from free-ranging populations. Liver Cu concentrations comparable to those associated with toxic effects in some domestic species were found in manatees from areas of high Cu herbicide use. The use of Cu herbicides for control of aquatic plants should be carefully managed in areas used intensively by manatees.