WARD, C.K.*; MENDONCA, M.T.; Auburn University; Auburn University: The Effect of Coal Fly Ash on Corticosterone, Testosterone and Metabolism in the Southern Toads, Bufo terrestris

At the Savannah River Site, South Carolina, Southern toads ( Bufo terrestris) bred in coal fly ash basins, which contain elevated levels of heavy metals in sediments. Toads in ash basin environments accumulate significant body levels of metals. Exposure to heavy metals has been found to be stressful, if not toxic, to many organisms; however toads with elevated metal levels still exhibit normal reproductive behavior. This observation raises questions on how toads are overcoming exposure to contaminant stress. Male toads were collected, bled, and weighed in early spring, for three years, from two sites, a coal fly ash basin and a control site. The toads were then divided into groups: toads collected at the control site and maintained on either control substrate (sand) and food (C>C), or heavy metal substrate (ash) and food (C>A), and toads collected at the contaminated site and maintained on either control substrate and food (A>C), or heavy metal substrate and food (A>A). Toads were weighed and blood samples were taken periodically for five months and analyzed for testosterone and corticosterone. Weight gain rate differed in ash exposed (C>A, A>A) and control toads. However there were no differences in standard metabolic rate or aerobic profile for any of the four groups of toads. C>C and A>A groups of toads did not differ in their hormone profiles. In contrast, toads transferred from control to ash (C>A) sediment exhibited a corticosterone peak in the second month and no increase in testosterone indicating a stress response. Toads transferred form ash to control (A>C) did not have increased corticosterone levels but did have elevated testosterone.