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WP11 Emerging Pollutants / Receptors
(SIB-1117-461645) Aquatic toxicity of fluorinated telomer acids.
MacDonald, M1, Sibley, P1, Dinglasan, J2, Mabury, S2, Solomon, K1, 1 Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada2 Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
ABSTRACT- The identification of fluorotelomer alcohols (FTOHs) as a probable atmospheric source of the globally recalcitrant perfluorinated carboxylic acids (PFCAs) has spurred interest in elucidating the chemical pathways of FTOH degradation to PFCAs. Biotic and abiotic oxidation of the FTOHs yields saturated and unsaturated fluorotelomer carboxylic acids (FTCAs). Lower volatility and higher water solubility of FTCAs compared with their FTOH counterparts suggest surface waters as a likely a repository for FTCAs but no fate or toxicity data exist for this environmental matrix. We assessed the toxicity of the 4:2, 6:2, 8:2 and 10:2 saturated (s) and unsaturated (u) forms of the FTCAs on Daphnia magna, Chironomus tentans and Lemna gibba. Acute toxicity studies indicated that all three species were most sensitive to FTCAs with chain lengths >=8 fluorocarbons (FCs). L. gibba was the most sensitive of the three to FTCAs of chain lengths <=8 FCs, with EC50 values for growth ranging from 0.71-10.04 mg/L for the 8:2 and 6:2 u-FTCAs, respectively. D. magna was the most sensitive to FTCAs of chain lengths >8 FCs, with EC50 values for immobility of 0.025 and 0.279 mg/L for the 10:2 s-FTCA and u-FCTA, respectively. In all three species, toxicity increased with increasing chain length from 6 to 8 FCs. This trend continued for D. magna through FC chain lengths of 10, but not for C. tentans or L. gibba. The s-FTCAs were generally more toxic than corresponding u-FTCAs with the exception of the 8:2 FTCA for L. gibba, and the 10:2 FTCA for C. tentans and L. gibba. A 60-d life cycle assay with C. tentans and the 8:2 s-FTCA resulted in toxicity thresholds for growth and mortality 5-6 times smaller than those measured in the acute study. The chain-length trends observed in the acute studies agree with those previously reported for the PFCAs, but toxicity thresholds were 1-4 orders of magnitude smaller for the FTCAs.
Key words: fluorotelomer carboxylic acids, Aquatic toxicity, Invertebrates, fluorinated surfactants
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