Meeting Abstract
A major feature of climate change is global temperature increase, which can affect toxicant exposure to wildlife in various ways. In this study, Lithobates pipiens tadpoles were exposed to two kinds of Great Lake pollutants at two temperatures, 18°C and 27°C, to examine the effects of temperature on toxicant elimination rates. The tadpoles were raised on a control diet to an asymptotic size and then fed diets containing a mixure of polychlorinated biphenyl congeners (PCB; 100 ng/g wet food) or polybrominated diphenyl ether congeners (PBDE; 1000 ng/g wet food) for two weeks. The tadpoles were then allowed to depurate for two weeks. Tadpoles were weighed, staged and collected for tissue residue analysis at the beginning and the end of depuration. Previous studies have established that both PCB and PBDE elimination rates in L. pipiens follow first order, single compartment kinetics, therefore allowing us to obtain rate constants with two sample time points. Temperature significantly affected the size of the animals, and the rate constants (ke) were corrected accordingly. PCB elimination rates were significantly higher at 27°C (ke = 0. 197) than at 18°C (ke = 0.058), with a Q10 value of 3.9, and PBDE elimination rates were also significantly higher at 27°C (ke = 0.170) than at 18°C (ke = 0.020), with a Q10 value of 10.9. The Q10 values of both compounds exceed the typical value of 2-3, indicating that warming temperatures, which are expected in climate change scenarios, may increase toxicant elimination much more than expected. How this will affect tissue residue levels will depend also on how temperature affects toxicant absorption. Funding provided by Sea Grant College Program, NOAA (Grant no. NA10OAR4170070, Project R/HCE-14).
