Does salinity mediate the toxicity of perfluorooctanesulfonic acid (PFOS) in an estuarine fish?

Perfluorooctanesulfonic acid (PFOS) is detected in estuarine environments, where salinity levels fluctuate regularly. We investigated the effects of salinity on the toxicity of PFOS in embryos and larvae of Cyprinodon variegatus. We crossed six PFOS treatments (0, 1-10,000 μg/L) with two salinities (10, 30 ppt). Larvae exposed to the highest concentration of PFOS under high salinity accumulated over twice the amount of PFOS compared to larvae maintained under low salinity. Embryonic survival was unaffected by PFOS, salinity, or their interaction. PFOS delayed time to hatch and increased salinity reduced time to hatch regardless of PFOS treatment; however, no salinity by PFOS interactions were observed. Conversely, PFOS and salinity interacted in the larval stage, with decreased survival at 30 ppt salinity. This is one of the first studies evaluating interactive effects of PFOS and high salinity and highlights the importance of assessing PFAS toxicity across life stages.
Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Maria Sepulveda reports financial support and administrative support were provided by Purdue University. Maria S. Sepulveda, Professor, Purdue University reports a relationship with Maria S. Sepulveda, Professor, Purdue University that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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