Assessment of potential health risks associated with ingesting heavy metals in fish collected from a hazardous-waste contaminated wetland in Louisiana, USA.

Significant adverse effects on environmental quality, ecosystem integrity, and human health have often been associated with improper disposal of hazardous materials. This study ascertains the levels of eight heavy metals in various fish species that were collected from a local hazardous-waste-contaminated wet-land and estimates the potential health risk that may be associated with consuming such fish. We examined a total of 53 fish samples representing 12 different species. The respective mean concentrations (ng/g) of arsenic, cadmium, chromium, copper, iron, lead, mercury, and nickel found in edible tissues were as follows: 72.5 +/- 103.1, 55.4 +/- 34.6, 97.4 +/- 111.7, 177.3 +/- 328.3, 2711.0 +/- 4469.6, 26.0 +/- 119.0, 32.7 +/- 75.3, and 81.5 +/- 178.9. For a 10-kg child eating 6.5 g of fish per day, the computed combined hazard index was 0.475 ; for 70-kg adults with a daily consumption of 6.5 g (general population), 30 g (sport fishermen), and 140 g (subsistence fishermen), the respective computed hazard indices were 0.068, 0.313, and 1.462. The results indicate that subsistence fishermen had the highest risk for systemic effects, with an exposure exceeding the Environmental Protection Agency (EPA) Reference Dose value. In a 10-kg child, such excess exposure would be reached--even with such single metals as arsenic and mercury--when applying the EPA-approved maximum fish consumption rate of 54 g/day to the general population. The cancer risk for arsenic, the only metal with an established cancer potency factor from oral exposure, varied from 8 x 10(-6) to 253 x 10(-6), indicating an exposure exceeding the widely accepted risk level of 1 x 10(-6) (one excess cancer per 10(6) population).