Toxicity, bioconcentration and maternal transfer of short chain perfluoroalkyl sulfonic acids (PFSAs) and perfluoroalkyl carboxylic acids (PFCAs) in the freshwater snail planorbella pilsbryi

Abstract

Toxicity, bioconcentration, and maternal transfer of short chain perfluoroalkyl sulfonic (PFSA) and carboxylic (PFCA) acids were investigated in the freshwater snail Planorbella pilsbryi. Toxicity of PFSAs and PFCAs was assessed in three life stages (embryos, juveniles, and adults) through a combination of tests of various durations. Toxicity, expressed as the Maximum Allowable Toxicant Concentration (MATC) for each substance, was calculated (MATC = 6 mg/L for PFOS and 55 mg/L for PFOA for embryonic development), and was influenced by the length of the fluorinated carbon chain (increasing with increasing chain length) and by the functional group (sulfonates being more toxic than carboxylates). Bioconcentration factors (BCFs) for C4, C6, and C8 perfluoroalkyl sulfonates and carboxylates ranged from 0.02 to 13.1 L/kg ww (whole body) and showed a pattern similar to toxicity, increasing with chain length and being greater in sulfonates than carboxylates. Concentrations measured in egg masses were similar to those in whole snails, and given the elevated frequency of egg laying, maternal offloading could explain whole-body concentrations lower than reported in other freshwater invertebrates.