Epizootics of cancer in fish associated with genotoxins in sediment and water.

Neoplasm epizootics in fish from a wide variety of freshwater, marine, and estuarine locations have been associated with genotoxins in sediment or water. The majority of cases have involved benthic or bottom feeding fish living in habitats with sediment contaminated by PAHs. The most common lesions involved in such epizootics include liver neoplasms, both biliary and hepatic, and skin neoplasms. Laboratory research has demonstrated the ability of fish to metabolize carcinogenic PAHs such as B(a)P into the ultimate carcinogen with the resulting formation of DNA adducts. Fish dosed with B(a)P or sediment extracts containing carcinogenic PAHs have developed skin and liver neoplasms. In the Black River, OH, neoplasm prevalence in wild brown bullhead has reflected PAH exposure as the latter has changed due to coke plant closures and remedial dredging activity. The weight of evidence supports a cause-and-effect relationship between exposure to genotoxins in sediment and water and neoplasm epizootics in wild fish populations.