Comparative analysis of sediment extracts from NOAA's bioeffects studies by the biomarker, P450 Reporter Gene System

Sediment samples collected from nine coastal and estuarine areas have been analyzed to determine response of a biomarker, P450 Reporter Gene System (RGS). This biomarker, using a transgenic cell line, detects the presence and potency of organic compounds that typically induce the CYP1A gene. Previous investigations have shown that sediments containing chemicals which produce a response of 60 or more mu g/g of benzo[a]pyrene equivalents (B[a]PEq) also exhibited a degraded community structure. RGS data from all study areas combined (527 samples) show that the mean response is 22.7 mu g/g B[a]PEq, and the mean upper 99% confidence interval is 32. We believe that sediments exhibiting B[a]PEq values of 32-50 are possibly contaminated to the extent that effects on benthic organisms may be observed, and those producing an RGS response of 60 and greater are likely to contain levels of chemicals that will produce chronic toxicity. The majority of the stations investigated produced responses below 32 mu g/g B[a]PEq. No samples from coastal southern California produced responses greater than 39. However, samples producing induction over 60 mu g/g B[a]PEq were: 50%, San Diego Bay; 16%, Delaware Bay; 8%, Sabine Lake; 4%, Northern Puget Sound; and 3%, Charleston Harbor. A strong statistical correlation was observed between the RGS responses and high molecular weight polycyclic aromatic hydrocarbon concentrations in the sediments from several of the study areas. Of the 2694 km(2) encompassed in the surveys, only 0.42% of the area exhibited responses above 32 mu g/g B[a]PEq, which represented 11.4 km(2). This assay is useful in identifying high levels of toxic and carcinogenic compounds in the sediments and predicting the potential impact of these chemicals on the biological community. (C) 1999 Elsevier Science Ltd. All rights reserved.