Reference values for exposure to PAH contaminants: Comparison of fish from Ohio and Mid-Atlantic streams.

Reference values for background exposures of benzo[a]pyrene (BAP)- and naphthalene (NAPH)-type metabolites were calculated for white sucker, northern hog sucker, and rock bass from the mid-Atlantic region based on the 90th percentile of a probability-based sample. Preliminary findings are presented for common carp. Bile was collected from fish and assayed for polycyclic aromatic hydrocarbon metabolites using the fluorescent method of Lin et al. Exposure reference values for white sucker were 0.3 microg/mg protein for BAP-type metabolites and 40 microg/mg protein for NAPH-type metabolites. Values from the Mid-Atlantic region were similar to those previously reported for the Eastern Corn Belt Plains (ECBP) ecoregion. Exposure reference values of BAP-type metabolites for rock bass were 0.3 microg/mg protein and 0.4 microg/mg protein for northern hog sucker. Exposure reference values of NAPH-type metabolites for rock bass were 30 microg/mg protein for rock bass and 50 microg/mg protein for northern hog sucker. Provisional values for common carp based on 39 observations are 0.4 microg/mg protein for BAP-type metabolites and 120 microg/mg protein for NAPH-type metabolites. Small streams exhibited the greatest range of exposures, 0.015-0.689 microg/mg protein for BAP-type metabolites and from 5.7 to 159 microg/mg protein for NAPH-type metabolites. Larger streams had 0.11-0.859 microg/mg protein for BAP-type metabolites and 10.2-286.5 microg/mg protein for NAPH-type metabolites. Exposure reference values for BAP and NAPH-type metabolites could be used as a basis of comparison of exposure to PAH contamination.