On the freshwater ecotoxicity and biodegradation properties of some common ionic liquids

Ecotoxicological tests, using OECD standard methods on some ionic liquids, have revealed that several have very high toxicity towards freshwater algae and the freshwater invertebrate Daphnia magna (similar to 10(4)-10(6) times more ecotoxic than methanol for the worse cases). In addition these compounds show high levels of toxicity to the microorganisms responsible for biodegradation in the environment. These materials have a significant potential to damage the aquatic ecosystem if released into water. We conclude that considerable care should be exercised in the choice of ionic liquids to be used in chemical processes at design stage and that contamination of aqueous effluent streams by these materials should be avoided wherever practicable.