文摘
Saturated and unsaturated fluorotelomer carboxylic acidshave been identified as intermediates in the degradationof fluorotelomer alcohols to perfluorinated carboxylic acids(PFCAs). Although surface waters are the likely environmentalsink for telomer acids, no fate or toxicity data exist forthis matrix. We assessed the acute toxicity of the 4:2, 6:2,8:2, and 10:2 saturated (FTCA) and unsaturated (FTUCA)fluorotelomer carboxylic acids to Daphnia magna, Chironomustentans, and Lemna gibba. In general, toxicity increasedwith increasing fluorocarbon (FC) chain length, particularlyfor telomer acids of 8 FCs. In addition, the FTCAs weregenerally more toxic than the corresponding FTUCAs. AcuteEC50s ranged from 0.025 mg/L (0.04 mol/L) for D. magna(10:2 FTCA, immobility) to 63 mg/L (167 mol/L) for C. tentans(6:2 FTCA, growth). While chain-length trends observedin the current study agree with those previously reportedfor PFCAs, the toxicity thresholds generated here areup to 10 000 times smaller. Our data provide the first evidencethat PFCA precursors are more toxic than the PFCAsthemselves.