Metabolic measures of male southern toads ( Bufo terrestris) exposed to coal combustion waste

Abstract

Southern toads ( Bufo terrestris) are found in coal fly ash collection basins associated with coal-burning electrical power plants. These basins contain large amounts of trace metals and organisms found in these basins are known to accumulate large quantities of metals. Studies on a variety of organisms exposed to trace metals found that they experience a significant increase in standard metabolic rate. We experimentally exposed southern toads to metal-contaminated sediment and food and measured changes in standard and exercise metabolic rates as well as changes in body, liver and muscle mass, blood glucose, and corticosterone. We found that toads exposed to trace metal contamination gained significantly less mass (18.3 %) than control toads (31.3%) when food was limited and experienced significantly decreased RQ after exercise. However, contaminated toads did not experience changes in standard (x¯ control = 0.114 ± 0.016 mL O 2 g − 1 h − 1 ; x¯ ash = 0.109 ± 0.013 mL O 2 g − 1 h − 1 , p = 0.08) or exercise metabolic rates (x¯ control = 0.53 ± 0.06 mL O 2 g − 1 h − 1 ; x¯ ash = 0.44 ± 0.04 mL O 2 g − 1 h − 1 , p = 0.47) plasma glucose levels ( p = 0.6), and hepatic or muscle percentage indices ( p > 0.2 in all cases) whether food was limited or not.