ARE YOU GONNA EAT THAT?Arsenic and Mercury Levels in Allegheny River Catfish and Implications for Human Consumption

摘要

This study examined arsenic and mercury concentrations in channel catfish (Ictalurus punctatus) caught for human consumption in the Allegheny River. Arsenic is a known human carcinogen and mercury is known to cause neurological disorders, particularly in fetuses and children. Subsistence and semi-subsistence anglers and their families are at risk of exposure.Catfish were caught at 4 distinct sites - Pittsburgh, Cheswick, Freeport and Ford City. They were measured for general characteristics such as weight, length, and sex, and tissue samples were taken and analyzed for heavy metal content. The study addressed main questions: Do levels of mercury and arsenic vary among the 4 sites and, if so, how? Do the levels of mercury and arsenic in these fish pose a threat to people who eat them regularly?Analysis of variance was used to determine group differences by location. Contrasts were performed to test for specific differences: Pittsburgh from the other three sites, and Cheswick, Freeport and Ford City from each other. Multiple regression analyses were conducted to determine if any of the other factors, weight, length or sex, had an impact on metals levels in addition to location. Assessments of risk to human consumers of these fish were conducted using US EPA guidelines and formulae.The Pittsburgh fish were found to have significantly different concentrations of both arsenic and mercury than the fish from the other sites. Mean levels of arsenic and mercury were observed to be lower in the Pittsburgh fish. No significant differences in contaminant levels were found between the Cheswick, Freeport and Ford City fish. Subsequent analyses were conducted combining these three locations into the Allegheny River group. Regression analyses showed minimal impact of weight and no impact of any other factor when controlling for location. Public Health Implications: Risk assessments found hazard quotients above 1 for all populations (children 3-8, children 9-15, women of childbearing age, other adults) based on 95% confidence intervals for mean concentrations of mercury. Arsenic levels also showed excess cancer risk for all populations. Current fish consumption advisories are inadequate to protect the health of regular consumers of these fish.