Dietary Exposure to Vanadium and Selenium: Assessment of Bioaccumulation and Physiological Effects in Hyla versicolor
Vanadium (V) is a common byproduct of fossil fuel combustion in solid wastes of ash and is known to have a variety of effects related to metabolic function in vertebrates. In studies of captive mammals, V has been found to modify metabolic and bioenergetic processes. Selenium is essential to animals when present at low concentrations, but is toxic to aquatic life at somewhat higher concentrations. Along with entering the aquatic systems through natural weathering of rocks and soils, Se is also released from coal ash disposal in the same way V does. However, the effect of V, as well as Se, on wildlife in natural systems is largely unknown. In prior studies we found that dietary exposure to environmentally relevant concentrations of V reduced growth, lipid content, and survival to metamorphic climax in larval leopard frogs (Rana sphenocephala). In the current, follow up study, we examined dietary effects of a wider range in concentrations of V and Se on larval grey tree frogs (Hyla versicolor). We fed larvae of the grey tree frog V at two concentrations, 360 and 720 ppm and Se and 12 and 60 ppm. Metal bioaccumulation, growth rates, lipid content, and metabolic rates were measured to assess the impact of V and Se exposure. Metabolic rates measured mid-way through larval development did not differ, however several physiological traits of metamorphs appeared to be altered. The results from this and our prior study suggest that V and Se may pose risks to recruitment potential of amphibians in sites contaminated with fossil fuel-derived wastes.
Rowe, C., A. Heyes, and J. Hilton*. 2011. Differential patterns of accumulation and depuration of dietary selenium and vanadium during metamorphosis in the gray treefrog (Hyla versicolor). Archives of Environmental Contamination and Toxicology 60:336-342.
Hilton, J.*, A. Heyes, and C. L. Rowe. 2008. Dietary exposure to vanadium and selenium: assessment of bioaccumulation and physiological effects in Hyla versicolor. 29th Annual Meeting in North America of the Society of Environmental Toxicology and Chemistry, Tampa, Florida.