Temperature determines toxicity: bisphenol A reduces thermal tolerance in fish.

Bisphenol A (BPA) is a ubiquitous pollutant around the globe, but whether environmental concentrations have toxic effects remains controversial. BPA interferes with a number of nuclear receptor pathways, including several that mediate animal responses to environmental input. Because thermal acclimation is regulated by these pathways in fish, we hypothesized that the toxicity of BPA would change with ambient temperature. We exposed zebrafish (Danio rerio) to ecologically relevant and artificially high concentrations of BPA at two acclimation temperatures, and tested physiological responses at two test temperatures that corresponded to acclimation temperatures. We found ecologically relevant concentrations of BPA (20 μg l(-1)) impair swimming performance, heart rate, muscle and cardiac SERCA activity and gene expression. We show many of these responses are temperature-specific and non-monotonic. Our results suggest that BPA pollution can compound the effects of climate change, and that its effects are more dynamic than toxicological assessments currently account for.