Hepatic CYP1A in winter flounder (Pleuronectes americanus) along the Northeast Coast: Results from the national benthic surveillance project

As part of the National Benthic Surveillance Project, cytochrome P4501A (CYP1A) and associated enzyme activities were measured in more than 700 samples of liver tissue collected from adult non-spawning winter flounder (Pleuronectes americanus). Between 1988 and 1994, animals were sampled annually from 20 sites, ranging from Penobscot Bay in Maine to Great Bay, New Jersey. Analyses performed were assays of aryl hydrocarbon hydroxylase (AHH) and ethoxyresorufinO-deethylase (EROD) activities, and immunoquantitation of CYP1A by enzyme-linked immunosorbent assay (ELISA). From 1988 through 1990, CYP1A was measured by all three methods, to help determine an appropriate method for assessing temporal trends and to allow for eventual comparisons to methods used in other monitoring efforts. From 1991 through 1994, assays were only done for hepatic AHH activity. Fish from virtually all sites showed induction of hepatic AHH activity, consistent with earlier reports, though fish sampled from sites in the coastal waters of Maine generally showed the lowest mean AHH activities. At sites where fish were sampled during three to six separate years (15 of the 20), individual data were analyzed for monotonic temporal trends. There were trends towards increasing AHH activities over time in fish from the Raritan Bay/Long Island Sound area, and generally increasing trends for sites near Massachusetts (especially Boston Harbor) and Rhode Island. A decreasing trend was noted in fish from Great Bay, New Jersey, and there appeared to be decreasing activities in fish from the nearshore waters of Maine, though these trends were not statistically significant at the α = 0.05 level. The induction of CYP1A is strongly associated with exposure to chemical contaminants, and while the consequences of widespread and increasing induction of CYP1A are not known, these results suggest that the measurement of this enzyme system in benthic fish can be a useful tool for monitoring our coastal ecosystems.