Unraveling the ecotoxicity of deep eutectic solvents using the mixture toxicity theory. (December 2018)

• Record Type: Journal Article
• Authors: Macário, Inês P.E.; Jesus, Fátima; Pereira, Joana L.; Ventura, Sónia P.M.; Gonçalves, Ana M.M.; Coutinho, João A.P.; Gonçalves, Fernando J.M.
• Is Part Of: Chemosphere. Volume 212(2018)
• Page Start: 890
• Page End: 897
• Publication Date: 2018-12
• Subjects: Quaternary ammonium salts -- Microtox -- Concentration addition -- Independent action -- Synergism -- Antagonism; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2018.08.153
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The interest on deep eutectic solvents (DES) has been increasing. However, the ecotoxicological profile of DES is scarcely known. Also, despite previous studies showed that DES components dissociate in water, none assessed DES toxicity using the classical and adequate models for mixture toxicity prediction - concentration addition (CA) and independent action (IA). This study evaluates the ecotoxicological profile of DES based on [N1111 ]Cl, [N2222 ]Cl and [N3333 ]Cl as hydrogen bond acceptors (HBA) combined with hydrogen-bond donors (HBD) vis. ethylene glycol and 1-propanol, through the Microtox ® Acute Toxicity Test. CA and IA with deviations describing synergism/antagonism, dose-ratio and dose-level effects were fitted to the toxicity data. Neither the starting materials nor DES were found hazardous to Alii v ibrio fischeri, in this specific case agreeing with the claimed "green character" of DES. Among the starting materials, ethylene glycol was the least toxic, whereas [N3333 ]Cl was the most toxic (30 min-EC50 = 96.49 g L −1 and 0.5456 g L −1, respectively). DES toxicity followed the same trend as observed for the salts: [N1111 ]Cl-based DES < [N2222 ]Cl-based DES < [N3333 ]Cl-based DES. The IA model, with specific deviations, adjusted better in 5 out of 6 DES. Antagonism was observed for [N1111 ]Cl-based DES, and synergism for [N3333 ]Cl-based DES and for 1-propanol:[N2222 ]Cl. The application of the mixture toxicity models represents a breakthrough in the problematic of assessing the toxicity of the countless number of DES that can be created with the same starting materials, since they provide the expected toxicity of any virtual combination between HBA and HBD. Highlights: Mixture toxicity theory successfully assesses the ecotoxicity of [Nxxxx ]Cl-based DES. DES toxicity followed the same trend as salts: [N1111 ]Cl< [N2222 ]Cl< [N3333 ]Cl. IA model, with specific deviations, adjusted better than CA in 5 out of 6 DES. Antagonism was found for [N1111 ]Cl-based DES and synergism for [N3333 ]Cl-based DES. DES toxicity cannot be predicted based solely on the toxicity of HBA and HBD.