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
(047) Preliminary investigation of selenium in water, bottom sediment, and biota, Great Salt Lake, Utah.
Waddell, Bruce*,1, Naftz, David2, Kimball, Briant2, Garbarino, John3, 1 U.S. Fish and Wildlife Service, Salt Lake City, UT, USA2 U.S. Geological Survey, Salt Lake City, UT3 U.S. Geological Survey, Denver, CO
ABSTRACT- Concern for avian resources and the sustainability of the brine shrimp industry has increased public interest and management concern on the south arm of Great Salt Lake (GSL). In response to these concerns, the U.S. Geological Survey (USGS) and U.S. Fish and Wildlife Service (USFWS) have conducted reconnaissance investigations of selenium (Se) and associated trace-element distributions in the water, bottom sediment, and biota from GSL. A sediment core containing a 250-year record of sediment deposition was collected by the USGS during 1998. Analysis of this core indicated that prior to the early 1900s, sediments deposited in GSL did not appear to be influenced by anthropogenic processes. Deposition of contaminated sediments began in the early to mid-1900s and sediments deposited in the later part of the 1900s contained increased amounts of contaminants. Water-column samples were collected by the USGS from 13 sites in 2001 and analyzed for a variety of dissolved (pass a 0.45 micron filter) trace elements. Se concentrations ranged from less than 20 to 68 micrograms per liter. Utah does not currently (2002) have a numeric water-quality standard for Se concentration in GSL; however, concern over the potential for bioaccumulation of Se to toxic concentrations in the food chain led the USFWS to sample and analyze biota utilizing the lake. The USFWS evaluated trace elements in biota (brine shrimp and eared grebes) and bottom sediment during 1994-2000. Sediments at selected sample sites exceeded the probable effects level (PEL) for marine sediment for As, Cu, Pb, and Se. The potential effects of these trace elements on birds using GSL for resting and feeding during migration was investigated by analysis of primary food sources (brine shrimp) in combination with analysis of eared grebe livers collected during fall and spring migration. Se concentrations in brine shrimp composites ranged as high as 4.5 micrograms per gram, dry weight. Limited sampling indicates that Se concentrations doubled in eared grebe livers between late September and early December, with geometric mean concentrations increasing from 6.2 to 10.8 micrograms per gram dry weight with sample sizes of 12 and 4, respectively.
Key words: metals, sediment, water, biota