Behaviour and toxicity of imidazolium based ionic liquids in soils

Abstract

This study contributes to a prospective hazard assessment of ionic liquids (ILs) for the terrestrial environment by analysing the (bio)availability (and therefore toxicity) of selected imidazolium based ILs in dependence on the soil properties organic matter, clay type and clay content. In general this hazard assessment is complicated by the structural heterogeneity within the substance class of ionic liquids which provides an almost unlimited number of theoretically available chemical structures. For this reason a tiered testing strategy was used to efficiently analyse the hazard potential of selected ILs starting with theoretical assumptions according to the T-SAR (Thinking in Terms of Structure Activity Relationships) concept followed by a set up of different test kits. Those assumptions were experimentally validated with an (eco)toxicological test battery and followed by a closer analysis of the (bio)availability of selected ILs. The bioavailability was assessed by using sorption/desorption studies as well as phytotoxicity assays. Additionally the issue of mixture toxicity was analysed for ILs mixtures in the presences and absence of the heavy metal cadmium.