Ecotoxicological study of glucose:choline chloride and sorbitol:choline chloride at different contents of water.

The search of new solvents is currently focused on deep eutectic solvents (DES). However, there are not many ecotoxicological studies in different biomodels of DES that allow knowing how these chemicals affect to the environment along the trophic chain. In this manuscript, two DES at different proportion of water have been prepared and characterized from the ecotoxicological point of view. These solvents are glucose:choline chloride (2:5) and sorbitol:choline chloride (3:2) at different contents of water. To carry out the ecotoxicological study, three biomodels have been used: bacteria Aliivibrio fisheri (A. fisheri), crustacean Daphnia magna (D. magna) and algae Raphidocelis subcapitata (R. subcapitata). The obtained results show that the ecotoxicity of these chemicals depends on the biomodel used and the amount of water, being toxicity values lower for chemicals with higher water content. However, it is important to highlight that the ecotoxicity for all chemicals is quite low with effective concentrations, EC50 values above 1000 mg/L in all the studied cases.

Ecotoxicity interspecies study of ionic liquids based on phosphonium and ammonium cations.

This work studies the effects of different bromide-based ionic liquids, with phosphonium and ammonium cations, towards several environmental biomodels: Daphnia magna, Allivibrio fischeri, Raphidocelis subcapitata. Results indicate that toxicity clearly depends on the biomodel, Allivibrio fischeri being the least sensitive one while Daphnia magna is more severely affected in the presence of the studied ionic liquids. In most of the cases, phosphonium moieties are less toxic than ammonium ionic liquids. Furthermore, a prediction about the oral toxicity and carcinogenicity of the studied ionic liquids has been also carried out, showing that these chemical structures may suggest significant toxicity but not present genotoxic or nongenotoxic carcinogenicity.

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.

Ecotoxicological study of six drugs in Aliivibrio fischeri, Daphnia magna and Raphidocelis subcapitata.

The presence of drugs in the environment is an emerging issue in the scientific community. It has been shown that these substances are active chemicals that consequently affect aquatic organisms and, finally, humans as end users. To evaluate the toxicity of these compounds and how they affect the environment, it is important to perform systematic ecotoxicological and physicochemical studies. The best way to address this problem is to conduct studies on different aquatic trophic levels. In this work, an ecotoxicological study of six drugs (anhydrous caffeine, diphenhydramine hydrochloride, gentamicin sulphate, lidocaine hydrochloride, tobramycin sulphate and enalapril maleate) that used three aquatic biological models (Raphidocelis subcapitata, Aliivibrio fischeri and Daphnia magna) was performed. Additionally, the concentration of chlorophyll in the algae R. subcapitata was measured. Furthermore, EC50 values were analysed using the Passino and Smith classification (PSC) method, which categorized the compounds as toxic or relatively toxic. All of the studied drugs showed clear concentration-dependent toxic effects. The toxicity of the chemicals depended on the biological model studied, with Raphidocelis subcapitata being the most sensitive species and Aliivibrio fischeri being the least sensitive. The results indicate that the most toxic compound, for all the studied biological models, was diphenhydramine hydrochloride. Graphical abstract.

QSAR study for predicting the ecotoxicity of NADES towards Aliivibrio fischeri. Exploring the use of mixing rules.

(Eco)toxicological information of natural deep eutectic solvents (NADES) is scarce, and thus, quantitative structure activity relationship (QSAR) models are an important tool for achieving the prediction of toxicity in this case. For that reason, in this manuscript, a new QSAR model for predicting the ecotoxicity of NADES towards the Aliivibrio fischeri biomodel, using mixing rules, is proposed. The main advantage of the method is that the individual components of the mixtures are molecularly modelled, and then, a mixing rule is used, which simplifies the process. For developing the model, a total of 11 descriptors for each component is used: the dissociation constant, partition coefficient, Van der Waals volume, Van der Waals surface area, topological polar surface area, solvent accessible surface area, minimum projection area, maximum projection area, minimum projection radius, maximum projection radius and molecular weight. The final obtained model includes the topological polar surface area and the dissociation constant, mechanistically interpreted as the ability of a NADES to transport through biological membranes and the severe negative effect of pH on the toxicity and biological response of Aliivibrio fischeri bacteria. The OECD Guidance Document on the Validation of (Quantitative) Structure-Activity Relationships is followed to develop the mathematical model.