In order to better illuminate the genotoxic effects of a “complex mixture” of anthropogenic chemical toxins, we have employed the comet assay to measure the level of genotoxicity induced in a sentinel animal species, Micropterus dolomieu. Our analysis reveals a significant level of genetic damage in Androscoggin River smallmouth bass that increases in a downstream gradient in parallel with toxic equivalent concentrations. Individual concentrations of recognized, anthropogenic chemical toxins in Androscoggin River fish tissues are measured on an annual basis as part of a State monitoring program. Subsequent fish consumption and river use advisories are issued based, in part, on these assessments.