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(M/MF144) Fluorinated surfactants; aquatic toxicity studies on primary and secondary trophic levels. Boudreau, Timothy1, Janutka, Richard1, Solomon, Keith1, Sibley, Paul1, Muir, Derek2, Mabury, Scott3, 1 2 3 ABSTRACT- Perfluorinated surfactants are industrial compounds widely used in stain-repellants and fire retardants. Known to be persistent and suspect to bioaccumulate, perfluorinated surfactants, may pose a risk to aquatic ecosystems over time. Laboratory bioassays performed on a variety of perfluorinated surfactants (PFSs) ranging from 3 to 10 carbons in length were used to evaluate toxicity on selected primary and secondary producers. The relative sensitivity of the algae Chlorella vulgaris and Selenastrum capricornutum, the floating macrophyte Lemna gibba and the invertebrates Daphnia magna and D. pulicaria was compared for each surfactant. When expressed as molar concentrations, perfluorooctane sulfonic acid (PFOS) was the most toxic to all test organisms. S. capricornutum had 50% inhibition values of 0.334 M and 0.198 M for PFOA and PFOS, respectively. D. magna had a LC50 for PFOA at 0.760 M and 0.282 M for PFOS, but exposure to PFSs < C8 had LC50 values greater than 3.8 M. The response trends were different for primary and secondary producers. A parabolic relationship was seen for primary producers when relative inhibition was compared to carbon chain length. No parabolic relationship was observed for either of the Daphnia species. S. capricornutum was the most sensitive test species for PFSs. A fluorescing dye technique aided by flow cytometry was used to determine a sense of causation with algal cell membranes. Both PFOA and PFOS were found to compromise membranes in a dose-dependant fashion. Since very little work has been done on the fate and toxicological implications of these compounds, this research will be used to support future environmental risk assessment. Key words: perfluorinated surfactants, toxicity, ScotchgardTM, cytometry |
