Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN, 47907-2033, United States.
Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN, 47907-2033, United States; Department of Environmental Science and Ecology, The College at Brockport, Brockport, NY, 14420, United States.
Chemosphere. 2019 Dec;236:124350. doi: 10.1016/j.chemosphere.2019.124350. Epub 2019 Jul 10.
Discovery of elevated concentrations of perfluoroalkyl substances (PFAS) in ground and surface waters globally has heightened concern over their potential adverse health effects. The effects of PFAS are known largely from acute toxicity studies of single PFAS compounds in model organisms, while little is understood concerning effects of mixtures on wildlife. To address this gap, we examined the acute and chronic effects of two of the most common PFAS (perfluorooctanesulfonic acid [PFOS] and perfluorooctanoic acid [PFOA]) and their mixtures on survival, growth, and development of American bullfrog (Rana catesbeiana) tadpoles. In 96 h acute toxicity tests, PFOS was 10X more toxic than PFOA and effects of the two chemicals in combination appeared additive. The effects of PFOS, PFOA, and their interaction varied by the sublethal endpoint under consideration in a 72 d exposure. Effects of PFAS on tadpole mass and developmental stage were largely driven by PFOS and there was no evidence of interactions suggesting deviations from additivity. However, for snout-vent length, reductions in length in mixture treatments were greater than expected based on the effects of the two chemicals independently (i.e. non-additivity). Further, effects on snout-vent length in single chemical exposures were only observed with PFOA. Our results highlight the importance of assessing combined effects of PFAS co-occurring in the environment and suggest caution in extrapolating the effects of acute toxicity studies to more environmentally relevant exposures. Future studies examining effects of environmentally relevant mixtures on wildlife will be essential for effective environmental risk assessment and management.
全球范围内发现地下水和地表水中存在高水平的全氟烷基物质 (PFAS)，这引起了人们对其潜在健康影响的高度关注。PFAS 的影响主要来自于单一 PFAS 化合物在模式生物中的急性毒性研究，而对于混合物对野生动物的影响知之甚少。为了解决这一差距，我们研究了两种最常见的 PFAS（全氟辛烷磺酸 [PFOS] 和全氟辛酸 [PFOA]）及其混合物对美洲牛蛙（Rana catesbeiana）蝌蚪的存活、生长和发育的急性和慢性影响。在 96 小时急性毒性试验中，PFOS 的毒性比 PFOA 高出 10 倍，两种化学物质组合的效果似乎具有加性。在 72 天的暴露试验中，PFOS、PFOA 及其相互作用的影响因所考虑的亚致死终点而不同。PFAS 对蝌蚪质量和发育阶段的影响主要由 PFOS 驱动，没有证据表明存在相互作用表明偏离加性。然而，对于吻肛长，混合物处理中的长度减少大于根据两种化学物质独立作用（即非加性）的预期。此外，在单一化学物质暴露中仅观察到 PFOA 对吻肛长的影响。我们的结果强调了评估环境中同时存在的 PFAS 联合效应的重要性，并表明在将急性毒性研究的结果外推到更具环境相关性的暴露时应谨慎。未来研究检查环境相关混合物对野生动物的影响对于有效的环境风险评估和管理至关重要。
