Ecotoxicity and biodegradability of pure and aqueous mixtures of deep eutectic solvents: glyceline, ethaline, and reline.

Most of the works carried out on deep eutectic solvents (DESs) make reference to their physicochemical properties, and the analysis of their toxicological behavior on the environment and biodegradability are still limited. In this work, an exhaustive study on the ecotoxicity of three pure deep eutectic solvents (reline, glyceline, and ethaline) and their mixtures with water (reline-water, glyceline-water, and ethaline-water) was carried out in different biomodels: bacteria (A. fisheri), crustaceans (D. magna), and algae (S. capricornatum). In addition, the amount of chlorophyll in the algae after exposure to the DESs was analyzed. Finally, the biodegradability of the studied DESs was also analyzed. The ecotoxic behavior strongly depends on both the biomodel tested and the presence of water in the mixture, resulting in low toxicities in all cases. Furthermore, most of the deep eutectic solvents studied can be considered readily biodegradable. A comparison of the ecotoxicity and biodegradability of these solvents under other conditions has also been provided, and a complete analysis is given.