Pharmaceuticals entering Lake Champlain and their combination effects on developing Zebrafish Embryos

Human-derived pharmaceuticals have been identified entering surface waters in the United States through wastewater effluent. While there is ample literature about what each compound alone does to aquatic life, little is known about the effects aquatic life may experience from the exposure to many different pharmaceuticals present in the environment. More specifically, are the combination of pharmaceuticals in the environment more detrimental to aquatic life than each pharmaceutical alone? Zebrafish embryos were used to model what aquatic life in Lake Champlain may experience. Vatovec et al (2016) determined that there are 51 environmentally-relevant human derived pharmaceuticals entering Lake Champlain through wastewater effluent. Out of the 51, acetaminophen, carbamazepine, and diphenhydramine were studied. Embryos were exposed to each pharmaceutical for three days at various concentrations and observed for any developmental defects. The sub-lethal concentration of each pharmaceutical was determined and then this specific concentration was used in subsequent combination experiments. Results indicated that the exposure to all three pharmaceuticals were more detrimental to embryonic development than each pharmaceutical alone. However, when pharmaceuticals were combined in groups of two, one of the groups was more detrimental to embryos than the combination of all three pharmaceuticals. Although concentrations used in this experiment were much higher than that found in the environment, the implications of this study are still important. It is necessary to determine and demonstrate at what concentration pharmaceuticals are detrimental to aquatic life so that environmental concentrations never reach the concentrations used in the current