Response of larval frogs to Corexit 9500

The use of dispersants in the Gulf of Mexico has created a number of environmental and human health concerns, chief among them are questions regarding the potential impact of Corexit 9500 on the health and fitness of Gulf wildlife. These studies were designed to use a biological toxicity test during post-fertilization and early development to evaluate Corexit 9500A effect on The Frog Embryo Teratogenesis Assay-Xenopus (FETAX) assay. Frog embryos were exposed to concentrations ranging from 1000 to 1 uL L^-1 for Corexit 9500 A. Various forms of malformations were recorded following exposure to Corexit 9500. These abnormalities included pharyngeal and thoracic edema, severe optic edema, and incomplete and reversed gut coiling. The percent of males was higher in the Corexit-treated groups, while control was closer to the expected 50:50 males to females ratio. In addition, a statistically greater number of hypomelanistic animals were observed in the Corexit-treated animals versus controls. Exposure of early life stage frogs to dispersants may exert chronic effects on health status of adults and as such consideration and evaluation of Corexit exposure to vulnerable life stages needs to be given high priority in the determination of risk and long-term impact and recovery of the ecosystem.