Hepatic lesions other than neoplasms in subadult flatfish from puget sound, washington: relationships with indices of contaminant exposure

Abstract

Liver neoplasms are rare in young wild fish; therefore, it is essential to consider toxicopathic liver lesions that occur earlier than neoplasms as biomarkers of contaminant exposure in studies where targeted or available fish are not adults. Also some exposure effects may be more reliably assessed in younger fish that have not yet migrated extensively. We addressed these issues by histologically examining subadult English sole, rock sole, and starry flounder captured from eight sites in Puget Sound, and by measuring fluorescent aromatic compounds (FACs) in bile and polychlorinated hiphenyls (PCBs) in liver. Neoplasms were detected rarely; higher prevalences of preneoplastic, regenerative, and degenerative lesions were detected in most species, primarily from contaminated sites, including hydropic vacuolation of hepatocytes and biliary cells in rock sole and starry flounder. These nomeoplastic lesion types are inducible in fish by exposure to various toxicants in the laboratory, and/or (in the case of hydropic vacuolation) are associated with contaminant exposure and liver neoplasia in adult wild fish. Prevalences of these ‘early’ lesions were significantly higher at the more contaminated sites, as determined by several statistical approaches, including logistic regression. Moreover, prevalences of most lesions in all three species correlated with mean bile FAC levels at the sites, and prevalences of some lesions in English sole correlated with liver PCB levels. The present findings further support the utility of certain liver lesions other than neoplasms as early indicators of biological damage in subadult as well as adult fish exposed to xenobiotics in the marine environment.