MP9 Metals and Bioaccumulation
Monday, 14 November 2005: 8:00 AM - 5:30 PM in Exhibit Hall

(BRY-1117-836620) Patterns of heavy metal bioaccumulation in hibernating toads, Bufo cognatus.

Bryer, P.¹, McBride, T.¹, Hooper, M.¹, McMurry, S.¹, ¹ The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX, United States

ABSTRACT- Dermal uptake has been recently established as a potential pathway for toads to accumulate the heavy metal cadmium. Due to the length of their hibernating season, up to 8 months, this places many xeric adapted toad species at significant risk for accumulating high levels of metals in their tissues. As a pilot study, we examined the patterns of metal bioaccumulation on Great Plains Toads, Bufo cognatus, over a 4 week period. The Great Plains Toad was chosen as a model species because of its widespread distribution, from Mexico to Canada, and highly fossorial habit. The exposure was generated by using soil collected from the Anaconda Superfund Site in Montana; which was the site of smelting and mining activities for 100+ years. The five treatments: control, "low", "medium", "SMARCO", and "high", were based on soil metal concentrations, with the "high" treatment soils containing 701 ppm As, 29 ppm Cd, 1346 ppm Cu, 589 ppm Pb, and 1142 ppm Zn. Hibernating toads were housed in individual chambers at 4°C. At three time points (one, two, and four weeks), four toads were collected from each treatment group to analyze for As, Cd, Cu, Pb, and Zn concentrations. Three tissue compartments were dissected to be analyzed separately: skin, liver, and carcass. The livers of week four toads contained elevated levels of cadmium and copper. There was no mortality during the experiment; however, by the fourth week, toads in the highest treatment level indicated impaired locomotor abilities, indicating potential metal induced health effects.

Key words: amphibian, dermal, soil