Larval amphibians rapidly bioaccumulate poly- and perfluoroalkyl substances

Poly- and perfluoroalkyl substances (PFAS) are ubiquitous contaminants that can bioaccumulate in aquatic taxa. Amphibians are particularly vulnerable to contaminants and sensitive to endocrine disruptors during their aquatic larval stage. However, few studies have explored PFAS uptake rates in amphibians, which is critical for designing ecotoxicology studies and assessing the potential for bioaccumulation. Uptake rates of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were measured for larval northern leopard frogs (Rana pipiens), American toads (Anaxyrus americans), and eastern tiger salamanders (Ambystoma tigrinum) during a 240-h exposure to 10 and 1000 mu g/L concentrations. We measured body burden and calculated bioconcentration factor (BCF) every 48 h during the experiments. For all species and exposures, body burdens often reached steady state within 48-96 h of exposure. Steady-state body burdens for PFOA and PFOS ranged from 3819 to 16,481 ng/g dry weight (BCF = 0.46-2.5) and 6955-489,958 ng/g dry weight (47-259 BCFs), respectively. Therefore, PFAS steady state occurs rapidly in the larval amphibians we studied and particularly for PFOS. This result reflects a high potential for PFAS trophic transfer because amphibians are often low in trophic position and are important prey for many aquatic and terrestrial species.