HP3 Metals in the Environment: Regulatory and Risk Concerns
254 Portland Ballroom
1:20 PM - 5:20 PM, Thursday
() A site–specific evaluation of US EPA's proposed chronic water quality criterion for selenium.
Parkhurst, B1, 1 HAF, Inc., Laramie, WY, USA
ABSTRACT- US EPA has proposed a new chronic water quality criterion for selenium based on the concentration in fish. This criterion was evaluated in Poison Spider Creek, WY. Concentrations of total selenium were measured in water, fish, and benthic macroinvertebrates at three sites upstream and three sites downstream of a tributary that contributed relatively high concentrations of selenium to the creek. The species composition and abundance of fish and invertetebrates also were assessed at each site. At downstream sites concentrations of selenium in fish and invertebrates exceeded the proposed criterion, while upstream sites had concentration less than the criterion. The species composition of fish and invertebrates were similar at upstream and downstream sites, as was the abundance of invertebrates. Fish, however, were much more abundant at downstream sites. It was concluded that the proposed criterion was more protective than necessary for this creek, probably as a result of differences in species sensitivities. USEPA's proposed criterion is based on studies with sunfish, while the fish species in Poison Spider are minnows and suckers that appear to be less sensitive to selenium. Sunfish are not present in the creek and are not native to this region.
Key words: water quality standard, selenium , fish, bioaccumulation