Fish biliary PAH metabolites estimated by fixed-wavelength fluorescence as an indicator of environmental exposure and effects

Biliary polynuclear aromatic hydrocarbon (PAH) metabolites have been studied since the mid 1980s as an indicator of exposure of fish to PAHs. However, the measurements of PAH metabolites are often costly and time-consuming. A simple and rapid method, fixed-wavelength fluorescence (FF), was used to measure the concentrations of benzo(a)pyrene (B[a]P)-type and naphthalene (NAPH)-type PAH metabolites in the bile of brown bullheads (Ameiurus nebulosus) collected from Old Woman Creek, Ottawa River, Cuyahoga River-harbor and Cuyahoga River-upstream. The biliary PAH metabolites in fish from the less contaminated Old Woman Creek were significantly lower than those from the industrially contaminated Ottawa and Cuyahoga rivers. The levels of biliary PAH metabolites were found to be related to the PAH sediment contamination for the four sites except Cuyahoga River-upstream, and to the prevalence of fish barbel abnormalities and external raised lesions observed in all rivers except Ottawa. Statistical analysis revealed a significant association between the occurrence of barbel abnormalities and concentrations of biliary NAPH-type metabolites and between the occurrence of raised lesions and concentrations of B[a]P-type metabolites. This study provides added evidence that FF is an effective bile analysis method for determining the exposure of fish to PAHs. This study also indicates that the measurement of PAH metabolites could help establish causal relationship between the chemical exposure and effects such as barbel abnormalities and raised lesions.