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Sublethal toxicity of diverse PFASs to three freshwater invertebrates: comparisons among species, structures, and mixtures
Citation:
Kadlec, S., W. Backe, R. Erickson, L. Glimsdal, R. Hockett, S. Howe, K. Lott, Dave Mount, I. Mundy, E. Piasecki, H. Sluka, J. Swanson, AND L. Votava. Sublethal toxicity of diverse PFASs to three freshwater invertebrates: comparisons among species, structures, and mixtures. Society of Environmental Toxicology and Chemistry (SETAC) North America, Pittsburgh, PA, November 13 - 17, 2022. https://doi.org/10.23645/epacomptox.21603807
Impact/Purpose:
Presentation to the Society of Environmental Toxicology and Chemistry (SETAC) annual meeting November 2022. This presentation will summarize our findings of sublethal toxicity of several classes of per- or poly-fluorinated alkyl substances (PFASs) to three freshwater invertebrate species, both in terms of individual chemical potency and as interactive toxicity of mixtures. These represent meaningful progress toward understanding how PFAS toxicity varies across chemical structures and species, inferring hypothetical groupings of PFASs with common mechanism of toxicity, and prioritizing compounds/species for further work involving body burden and mixture toxicity. Our intended audience is ecotoxicologists and risk assessors from government, industry, and academia, at an international professional conference. This work is taking place under the Safe and Sustainable Water Resources National Program. Specifically, it is occurring under SSWR 3.2.2.
Description:
The majority of experimental data on the ecological effects of per- or poly-fluorinated alkyl substances (PFASs) are for a small number of compounds within the structurally diverse set of PFASs whose potential ecological risks are of interest. There is a clear need for a systematic understanding of how PFAS toxicity varies across chemical structures and species. To address this need, we have generated aquatic toxicity data for 16 PFASs among the perfluorinated sulfonate, perfluorinated carboxylic acid, perfluorinated sulfonamide, and fluorotelomer classes, with chain lengths of 3 to 10 fluorinated carbons. Toxicity tests were conducted with three freshwater invertebrate species (Ceriodaphnia dubia, Chironomus dilutus, and Hyalella azteca) using 7-d exposures that allowed measurements of sublethal endpoints (growth or reproduction). Sublethal effect concentrations varied widely: some chemicals caused no effects up to 200 mg/L, whereas others reduced growth by 50% in the 0.01 mg/L range. Among all PFAS classes, toxicity generally increased with increasing chain length. A notable exception was toxicity of perfluorinated sulfonates to C. dilutus, which exhibited the greatest sensitivity to PFOS and PFNS (8 and 9 carbons, respectively), and were less sensitive to PFASs having shorter (<8 carbons) or longer (>9 carbons) chain lengths. Perfluorinated sulfonates were dramatically more toxic to C. dilutus than were perfluorinated carboxylates, by as much as three orders of magnitude. In strong contrast, those two classes had similar effect concentrations and relatively low toxicity to C. dubia and H. azteca (EC50 values in the 1 to 200 mg/L range). Comparing across PFASs with similar chain lengths, perfluorinated sulfonamides were the most toxic class to all three species. This presentation discusses how structure-toxicity patterns observed among and between species facilitate hypothetical groupings of compounds with common mechanism of action and prioritization of compounds/species for further studies involving body burden and mixture toxicity. We also present results of binary mixture studies to characterize toxic interactions and infer similar/dissimilar mechanisms. The views expressed in this presentation are those of the authors and do not necessarily reflect the views or policies of the United States Environmental Protection Agency.
URLs/Downloads:
DOI: Sublethal toxicity of diverse PFASs to three freshwater invertebrates: comparisons among species, structures, and mixtures
SETAC 2022 SUBLETHAL TOXICITY OF DIVERSE PFASS TO 3 FW INVERTEBRATES_FOR STICS.PDF (PDF, NA pp, 1846.647 KB, about PDF)