Polycyclic aromatic hydrocarbons in fish and crayfish from the Calumet region of southwestern Lake Michigan

We identified and quantified polyaromatic hydrocarbons (PAHs) in six aquatic taxa from the Calumet region of southwestern Lake Michigan in order to examine their differential exposure to and health risks from PAH. There was a high degree of variation in PAH concentrations across and within sites. Mean concentrations of total PAH were high in alewife (1,064 ng/g) and minnows (345 ng/g) collected from the Indiana Ship Canal, when compared to other taxa and locations. Concentrations of PAH in sunfish were relatively low (10 to 79 ng/g), even where environmental concentrations were elevated. In sunfish, regardless of location, concentrations of CHR, FLA, FLU, PHE and PYR were high whereas DBA, IPE, BAP, BBF, BGP and BKF concentrations were low. PAH concentrations in crayfish exceeded those of other taxa at three of four locations where they co-occurred. PAH profiles were similar in crayfish, sunfish and minnows from locations where sediment concentrations were low. Profiles for crayfish and minnows from a location where sediment concentrations were elevated displayed lower concentrations of ACY, and higher concentrations of BAA, BBF, and BKF, than those from the other three locations. In contrast, the profiles in sunfish from those three locations were similar. The PHE/ANT and FLA/PYR ratios for crayfish, minnows and sunfish suggested that the primary sources at most locations were pyrogenic, although some sites had strong petrogenic influences. Toxic equivalency factors in biota generally reflected the magnitude of sediment contamination. In three of four locations where they co-occurred, TEQs were higher in crayfish than in sunfish and minnows. Sunfish had higher TEQs than minnows at most, though not all, locations; TEQs were notably higher in minnows as compared to sunfish from the Little Calumet River. The selection of aquatic species as sentinels of PAH exposure and risks needs to consider differences in ecologies of taxa as well as the relative magnitude of sediment contamination.