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PT06 Contaminants-Receptor Interactions: New Challenges
(PT099) Toxicity of Ionic Liquids to Aquatic Organisms.
Bernot, R1, Evans-White, M1, Docherty, K1, Lambert, G1, Brennecke, J2, Lodge, D1, Kulpa Jr., C1, Brueseke, M1, 1 University of Notre Dame, Department of Biological Sciences, Notre Dame, IN, USA2 University of Notre Dame, Department of Chemical Engineering, Notre Dame, IN, USA
ABSTRACT- Room temperature ionic liquids (ILs) are a new class of chemicals being adopted by industry as environmentally-friendly solvent substitutes. While ILs are relatively benign to the atmosphere because they are non-volatile, their impacts on aquatic organisms and communities are unknown. To assess the relative toxicity of imidazolium-based ILs, we conducted acute and chronic toxicity bioassays using a range of freshwater organisms. Acute toxicities of Daphnia magna to ILs with the 1-n-butyl-3-methylimidazolium (bmim) cation were similar (LC50 values ranged from 10.8 to 19 ppm). Daphnia magna also produced fewer offspring at older ages when raised in imidazolium ILs. Ionic liquids with Na as the cation, however, were less toxic to D. magna (LC50 >9000 ppm). Imidazolium ILs were relatively less toxic to the freshwater snail, Physa acuta (LC50 values ranged from 43.2 to 882.3 ppm), and also much more variable depending on the anion present. Grazing rates of P. acuta, however, were significantly lower in the presence of small IL concentrations (<1 ppm), suggesting chronic and non-lethal IL effects. Toxicity of bmim ILs to the bacterium Vibrio fisheri also depended on the anion, with the greatest toxicity to bmimCL (LC50=14.3 ppm) and least toxicity to bmim bistriflimide (LC50>1000 ppm). These preliminary results illustrate that IL toxicity differs among aquatic organisms, and provide baseline information about the potential risks of ILs to aquatic ecosystems. Ongoing research with algae (Selanastrum sp.), aquatic plants (Lemna minor), midge larvae (Chironomus sp.), and fish (Pimephales promelas) will assess the toxicity of imidazolium- as well as pyridinium-based ILs across a range of organisms and trophic levels.
Key words: toxicity, Ionic Liquids , aquatic organisms
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