Polycyclic aromatic hydrocarbons (PAHs) in livers of California sea otters

Concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were measured in livers of 81 adult female sea otters collected along the California coast in 1992–2002. Concentrations of ∑PAHs in livers of sea otters were in the range of 588–17 400 ng/g lipid wt (mean: 3880 ng/g, lipid wt). On a wet weight basis, the concentrations ranged from 17 to 1430 ng/g (mean: 146 ng/g). Overall, di- and tri-cyclic aromatic hydrocarbons, namely, naphthalene, fluorene, phenanthrene/anthracene, and acenaphthylene, were the predominant compounds found in the livers. Although petroleum-related sources appear to be the major contributors to PAH exposure in sea otters, exposure sources varied by geographical sub-regions. Dibenz[a,h]anthracene was found to comprise a significant proportion of the ∑PAH concentrations in sea otters from the northern sub-region of the study area. No significant difference existed in the concentrations of ∑PAHs among sea otters that died from infectious diseases, emaciation, and noninfectious causes. Concentrations of ∑PAHs in livers of sea otters decreased significantly from 1992 to 2002. Because of the rapid metabolism of PAHs in marine mammals such as sea otters, further studies examining the association of PAHs with health effects should determine hydroxylated metabolites in livers.