title: Biodegradability and aquatic toxicity of quaternary ammonium-based gemini surfactants: Effect of the spacer on their ecological properties.
abstract: Aerobic biodegradability and aquatic toxicity of five types of quaternary ammonium-based gemini surfactants have been examined. The effect of the spacer structure and the head group polarity on the ecological properties of a series of dimeric dodecyl ammonium surfactants has been investigated. Standard tests for ready biodegradability assessment (OECD 310) were conducted for C12 alkyl chain gemini surfactants containing oxygen, nitrogen or a benzene ring in the spacer linkage and/or a hydroxyethyl group attached to the nitrogen atom of the head groups. According to the results obtained, the gemini surfactants examined cannot be considered as readily biodegradable compounds. The negligible biotransformation of the gemini surfactants under the standard biodegradation test conditions was found to be due to their toxic effects on the microbial population responsible for aerobic biodegradation. Aquatic toxicity of gemini surfactants was evaluated against Daphnia magna. The acute toxicity values to Daphnia magna, IC50 at 48 h exposure, ranged from 0.6 to 1 mg/L. On the basis of these values, the gemini surfactants tested should be classified as toxic or very toxic to the aquatic environment. However, the dimeric quaternary ammonium-based surfactants examined result to be less toxic than their corresponding monomeric analogs. Nevertheless the aquatic toxicity of these gemini surfactants can be reduced by increasing the molecule hydrophilicity by adding a heteroatom to the spacer or a hydroxyethyl group to the polar head groups.
authors.affiliation: Department of Chemical and Surfactant Technology, Institute of Advanced Chemistry of Catalonia, IQAC-CSIC, Jordi Girona 18-26, 08034, Barcelona, Spain. Electronic address: teresa.garcia@iqac.csic.es.
authors.forename: M Teresa
authors.initials: MT
authors.lastname: Garcia
authors.affiliation: Laboratory of Microbiocides Chemistry, Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614, Poznań, Poland. Electronic address: olga.kaczerewska@wp.pl.
authors.forename: Olga
authors.initials: O
authors.lastname: Kaczerewska
authors.affiliation: Department of Chemical and Surfactant Technology, Institute of Advanced Chemistry of Catalonia, IQAC-CSIC, Jordi Girona 18-26, 08034, Barcelona, Spain. Electronic address: isabel.ribosa@iqac.csic.es.
authors.forename: Isabel
authors.initials: I
authors.lastname: Ribosa
authors.affiliation: Laboratory of Microbiocides Chemistry, Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614, Poznań, Poland. Electronic address: brycki@amu.edu.pl.
authors.forename: Bogumił
authors.initials: B
authors.lastname: Brycki
authors.affiliation: Laboratory of Microbiocides Chemistry, Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614, Poznań, Poland. Electronic address: p_materna@wp.pl.
authors.forename: Paulina
authors.initials: P
authors.lastname: Materna
authors.affiliation: Laboratory of Microbiocides Chemistry, Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614, Poznań, Poland. Electronic address: madrgas@wp.pl.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Drgas
mesh_terms: D000818:Animals; D001673:Biodegradation, Environmental; D001711:Biotransformation; D003621:Daphnia / Q000187:drug effects; D054750:Ecotoxicology; D000644:Quaternary Ammonium Compounds / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000633:toxicity*; D013501:Surface-Active Agents / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000633:toxicity*; D014867:Water / Q000737:chemistry*
chemical_list: D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D014867:Water
keywords: Aerobic biodegradation; Aquatic toxicity; Daphnia magna; Gemini surfactants; Mineralization; Spacer