PARENT SESSION
SA5 - Selenium: Toxicity Investigations of Ecological Risks
Chair: Harb, John1, 1 nharb@do.usbr.gov
8:00 AM to 12:00 PM - Sunday, 17 November 2002
Room Ballroom D
(041) Development of a draft aquatic life criterion for selenium based on concentrations in fish tissue.
Delos, Charles*,1, McIntyre, Dennis2, Linton, Tyler2, Clement, William2, 1 U.S. EPA, Washington, DC, USA2 Great Lakes Environmental Center, Traverse City, MI, USA
ABSTRACT- In Spring 2002, U.S. EPA published a draft ambient water quality criteria document for selenium. The criterion is intended for the protection of aquatic life. The chronic criterion is expressed as a whole-body fish tissue concentration: 7.9 mg/kg dw. The intent of basing the criterion on a tissue concentration rather than a water concentration is to improve the reliability of the criterion by removing the potential site-to-site variability of the bioaccumulation factor from the criterion formulation. Because under real world conditions, aquatic life is exposed to selenium primarily through diet, ordinary toxicity tests involving contaminated water but an uncontaminated diet are not fully appropriate. The criterion is based instead on laboratory studies where exposure included a contaminated diet, and on field studies where the food chain was contaminated. The data underlying the draft 7.9 mg/kg criterion value will be outlined, and evidence suggesting that the criterion should be set either higher or lower than the draft value will be discussed. Implications for piscivorus birds will also be discussed.
Key words: selenium, criteria, bioaccumulation, aquatic life