Summary

Description

The John Heinz National Wildlife Refuge at Tinicum JHNWRT is located along Darby Creek near its confluence with the Delaware River, south of Philadelphia, Pennsylvania USA. The Refuge hosts the largest freshwater tidal marsh in Pennsylvania, about 142 hectares. A 3.2 km reach of Lower Darby Creek was listed as an Environmental Protection Agency Superfund site in 2001 due to a history of contamination and documented sources including Folcroft and Clearview Landfills. In June 2003, for an assessment of habitat quality, we collected 31 brown bullheads Ameiurus nebulosus 260 mm total length, from a 1.6 km stretch of Darby Creek near the middle of the Superfund area. The objective was to determine the prevalence of liver and skin tumors, preneoplastic lesions, and barbel abnormalities. We reported a 26 8 of 31 prevalence of liver tumors, primarily hepatocellular carcinomas. Total PAH concentrations in sediments within the sampling area were documented by an EPA contractor to average 48.9 ppm maximum: 64.8 ppm. Liver tumor prevalence was significantly p0.001, chisquare test higher than that observed in an area of the Tuckahoe River MD, used as a reference area prevalence 4 5 of 117. It also exceeded the 5 criterion suggested as indicative of highly contaminated areas. Skin tumor prevalence was not significantly different between locations Darby: 231 6, Tuckahoe: 1117 1, p0.21, and was less than the 12 suggested criterion. Barbel abnormalities were not significantly different Darby: 331 10, Tuckahoe: 387 3, p0.38. In view of the high liver tumor prevalence and high concentrations of PAHs, we recommend a followup study, including analysis of biomarkers such as biliary PAH metabolites and DNA adducts. Future tumor surveys are recommended for monitoring the effects of active or passive remediation.