PARENT SESSION
Oral Session #41: Agroecology and Urban Ecology. Presiding: M. Liebman.
Wednesday, August 8, 2001. 8:00 AM to 12:15 PM. Hall of Ideas L&M.
Are current metals criteria adequate?
ROSI-MARSHALL, EMMA1, MEYER, JUDITH1, NEUMANN, KLAUS2, GRAHAM, ELIZABETH3, 1 2 3
ABSTRACT- Currently, the US EPA only regulates dissolved trace metals in surface waters. Metals associated with suspended particles and sediments are ignored. The dissolved concentrations of Cd, Pb and As in the Chattahoochee River, within and below metropolitan Atlanta, are consistently lower than the water quality criteria, suggesting the river is not contaminated. However, our findings indicate that Cd and Pb concentrations in the tissues of caddisflies are correlated with the concentration of these contaminants sorbed to particles, but are not correlated with dissolved concentrations. In addition, arsenic is moving through the food web, from insects to fishes, with concentrations in the fishes high enough to pose serious threat to humans consuming these fishes. Mercury is currently regulated using the concentration sorbed to particles. Arsenic appears to be behaving like mercury in the food web, but is regulated very differently. Surveys conducted demonstrate that people are consuming fish at higher rates than advisable by EPA fish consumption guidelines. We argue that the standards in place are inadequate to protect the biota from contamination through trophic exposure and are not protective of humans who consume fish.
KEY WORDS: metals, water quality, trophic transfer