TWENTY-THIRD ANNUAL EASTERN FISH HEALTH WORKSHOP JOHN CARVER INN, PLYMOUTH, MA 30 MARCH - 2 APRIL, 1998 Prevalence And Histology Of Liver Neoplasms In Brown Bullhead, Ameiurus nebulosus, From The Anacostia River John C. Harshbarger1, Eric B. May2, Alfred E. Pinkney3, and Mark J. Melancon4 1Registry of Tumors in Lower Animals, Dept. of Pathology, George Washington University Medical Center, 2300 I St NW, Washington, DC 20037; 2MD Dept of Natural Resources, 904 S Morris St, Oxford, MD 21654; 3USFWS/Chesapeake Bay Field Office, 177 Admiral Cochrane Dr, Annapolis, MD 21401; USGS/Patuxent Wildlife Research Center, Laurel, MD 20708 Brown bullhead tumors seem to be related to carcinogenic PAH's in the sediment of three tributaries of the Potomac River near Woodbridge, Virginia(Pinkney et al. SETAC Meeting Abstracts, p 33, 1997). The objective was to determine tumor prevalence in brown bullhead from the Anacostia River, a more heavily polluted Potomac River tributary 25 miles north, which is impacted by storm sewers, marinas, a power plant, a navy yard, roads, railroad, etc. Twenty fish >279 mm were netted near the mouth in 1992, necropsied, tissues blocked and formalin fixed on site. Fifteen had multiple hepatocellular carcinomas and one additional fish had an incipient liver neoplasm, i.e. - a focus of hepatocellular alteration. Two fish also had cholangiomas which are low grade bile duct neoplasms. Sixty fish >259 mm were netted near a railroad bridge three miles upstream in 1996, necropsied, blocked and fixed. Two-thirds had tumorigenic liver lesions. About half of the fish with liver lesions had hepatocellular carcinomas and/or cholangiocarcinomas. The other half had lower grade liver tumors. Thirteen fish had skin neoplasms, nine of which had epidermal papillomas and four had squamous cell carcinomas. Thirty fish collected in 1996 each from two relatively clean but not pristine reference sites were 90 and 93 percent liver tumor free. Median values for p450 liver enzymes and for bile metabolites were higher in fish from the 1996 Anacostia survey than from the reference sites. In conclusion, the Anacostia River surveys are consistent with the Woodbridge survey and studies elsewhere in showing a relationship between brown bullhead liver tumors and levels of pollution. The two Anacostia River surveys are also consistent with studies elsewhere in showing higher tumor prevalence in longer, therefore, older fish.   Return to 23rd Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page