Evaluating the Health of the Potomac River Watershed:

High Rate of Tumors in Catfish from the Anacostia River in Washington, D.C.

The final report on a 2000-2001 tumor survey of brown bullheads in the Anacostia River is now available. The report, entitled "Tumor prevalence and biomarkers of exposure and response in brown bullheads (Ameiurus nebulosus) from the Anacostia River, Washington, D.C. and Tuckahoe River, Maryland." is available through the Service's Chesapeake Bay Field Office. Contact Info.

A U.S. Fish and Wildlife Service survey of the tidal Potomac River watershed found that brown bullhead (Ameiurus nebulosus), a species of catfish, collected from the Anacostia River in Washington, DC had high rates of both liver and skin tumors. Tumor rates in freshwater and saltwater fish have been used as an indicator of pollution. It is believed that tumors are caused by exposure to cancer causing-chemicals in sediments. Brown bullheads feed on worms and other invertebrates on the river bottom and bury themselves in the mud during winter. Because toxic chemicals often accumulate in sediments, pollution problems are frequently observed in bottom-dwelling species. A fish consumption advisory, issued in 1995 for the District of Columbia's portion of the Anacostia and Potomac Rivers, already urges the public not to eat catfish, carp and eels from those areas.

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Fifty percent of the fish collected from the Anacostia River near the CSX Railroad Bridge in the spring and 60% of those collected in the fall had liver tumors. In addition, a record 68% of the fish collected at a location near a combined sewer outfall were found to have liver tumors."These are comparable to the highest reported liver tumor rates in studies conducted in the Great Lakes, where rates above 9% indicate contamination" reports lead author, Fred Pinkney, an Environmental Contaminants biologist with the Service's Chesapeake Bay Field Office.

The survey found that the liver tumor rate in Neabsco Creek, a Virginia tributary of the Potomac located about 25 miles down river from Washington, DC was also high (17%). Neabsco Creek borders the Featherstone National Wildlife Refuge, managed by the Service.

Tests on fish and sediments suggest that exposure to polynuclear aromatic hydrocarbons (PAHs), identified as carcinogens in laboratory tests, may be responsible for the tumors. PAHs are found in petroleum, coal, and other fossil fuels. The most toxic forms of PAHs are formed from burning these fuels. PAHs enter rivers through runoff from roads and storm sewers, through spills, and from the atmosphere. The recently released report reveales that high concentrations of polycyclic aromatic compound-DNA adducts were found in both age >3 and age 1-2 Anacostia bullheads.

Surveys such as this may affect the issuance of fish consumption advisories. For example, as a result of the tumor research done in the Great Lakes, a consumption advisory was issued. These advisories inform the public that high concentrations of chemical contaminants have been found in local fish and wildlife and include recommendations to limit or avoid consumption of certain fish and wildlife species from specific waterbodies or waterbody types.

The survey report recommends using tumor surveys to monitor areas of the Chesapeake Bay with contaminated sediments. Such studies could be conducted before and after the source of the contaminants is controlled or cleaned up to determine the efforts success. Studies in a tributary of Lake Erie showed that tumor rates decreased following closure of an industrial plant that was the major PAH source. The brown bullhead survey is part of a larger effort involving the Service, other federal agencies and local groups to identify the sources of pollutants in the Anacostia river, determine their effects on fish and wildlife and recommend appropriate cleanup measures.

Fred Pinkney 410 573-4519
Pinkney, A.E., J.C. Harshbarger, E.B. May, and W.L. Reichert. 2002. Tumor prevalence and biomarkers of exposure and response in brown bullheads (Ameiurus nebulosus) from the Anacostia River, Washington, D.C. and Tuckahoe River, Maryland. CBFO-C02-07.


US Fish and Wildlife Service, Chesapeake Bay Field Office.

Last updated: February 13, 2013