Research Product

The mummichog, Fundulus heteroclitus, is one of the most abundant teleost fishes inhabiting salt marshes of the Atlantic coast of North America. Although the geographic range of this small cyprinodontid extends from Nova Scotia, Canada, to northern Florida, USA, local subpopulations are thought to be largely non-migratory. This, and it's adaptability to laboratory conditions, has led to the increasing use of this species as a bioassay organism in aquatic toxicology and as a sentinel of environmental quality. We recently reported high prevalences of liver neoplasms and associated lesions in mummichog inhabiting a polycyclic aromatic hydrocarbon (PAH) contaminated environment in Virginia, USA. This site is adjacent to a wood treatment facility that has treated railroad ties, pilings, and telephone poles with creosote and pentachlorophenol since the late 1920s. In 1991, this facility was placed into the U.S. Environmental Protection Agency's (EPA) Superfund Program and wood treatment operations were suspended. However, the property continues to be used to store timbers, and the adjacent aquatic habitat remains heavily contaminated. In addition to the hepatocellular neoplasms, mummichog from this site also exhibit elevated prevalences of neoplasms derived from biliary, exocrine pancreatic, vascular, lymphoid, and renal tissues. The extremely high PAH concentrations in sediments at this site (e.g., 2200 mg/kg dry wt), the diversity of the tumorigenic response, and the absence of neoplasms in fish from a mildly contaminated habitat only about 0.5 km away have suggested a chemical etiology for these lesions. Histopathology has recently gained acceptance in several U.S. pollution monitoring programs, and morphologic characterizations of tissue alterations in fish from polluted habitats have been given a high priority. The objective of this communication is to report histology and prevalence data for the hepatic and extra-hepatic proliferative lesions and neoplasms observed in mummichog from the above described creosote-contaminated environment.