title: A comparative study of the terrestrial ecotoxicity of selected protic and aprotic ionic liquids.
abstract: Ionic liquids (ILs) are a fairly new and very promising group of compounds with a vast variety of possible structures and uses. They are considered to be potentially "green", but their impact on the environment tends to be neglected or not studied enough, especially when it comes to terrestrial ecotoxicity, where there are very few studies performed to date. This work presents a comparative study of the terrestrial ecotoxicity of selected representatives of two ILs groups: a new family of protic ILs (derived from aliphatic amines and organic acids) and some frequently used aprotic ILs (substituted imidazolium and piridinium chlorides). Toxicity of the ILs towards three terrestrial plant species (Allium cepa, Lolium perenne and Raphanus sativus) and soil microorganisms involved in carbon and nitrogen transformation was analyzed. Protic ILs have shown no toxic effect in most of the tests performed. The EC50 values for aprotic ILs are various orders of magnitude lower than the ones for protic ILs in all of the tests. The most toxic ILs are the most complex ones in both of the analyzed groups. Protic ILs seem to have a potential for biodegradation in soil, while aprotic ILs exhibit inhibitory effects towards the carbon transforming microbiota. These findings indicate that protic ILs can be considered as less toxic and safer for the terrestrial environment than the aprotic ILs.
authors.affiliation: Unitat d'Edafologia, Faculty of Pharmacy, University of Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain. Electronic address: brezana@hotmail.com.
authors.forename: Brezana
authors.initials: B
authors.lastname: Peric
authors.affiliation: Unitat d'Edafologia, Faculty of Pharmacy, University of Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Sierra
authors.affiliation: Unitat d'Edafologia, Faculty of Pharmacy, University of Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Martí
authors.affiliation: Unitat d'Edafologia, Faculty of Pharmacy, University of Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain.
authors.forename: Robert
authors.initials: R
authors.lastname: Cruañas
authors.affiliation: Unitat d'Edafologia, Faculty of Pharmacy, University of Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain.
authors.forename: Maria Antonia
authors.initials: MA
authors.lastname: Garau
mesh_terms: D001673:Biodegradation, Environmental; D002244:Carbon / Q000378:metabolism; D052578:Ionic Liquids / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D008129:Lolium / Q000187:drug effects* / Q000502:physiology; D009584:Nitrogen / Q000378:metabolism; D019697:Onions / Q000187:drug effects* / Q000502:physiology; D031224:Raphanus / Q000187:drug effects* / Q000502:physiology; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*
chemical_list: D052578:Ionic Liquids; D012987:Soil; D012989:Soil Pollutants; D002244:Carbon; D009584:Nitrogen
keywords: Aprotic ionic liquids; Carbon and nitrogen transformation; Phytotoxicity; Protic ionic liquids; Terrestrial ecotoxicity