Predicting anionic surfactant toxicity to Daphnia magna in aquatic environment: a green approach for evaluation of EC₅₀ values

The median effective concentration (EC₅₀) is the concentration of a substance expected to produce a specific effect in 50% of the populations with a certain density under defined conditions. This parameter is expressed as an acute toxicity and is obtained via chemical toxicity testing. But, the laboratory work is time-consuming, expensive, and not eco-friendly. Therefore, to predict EC₅₀ for new anionic surfactants, a quantitative structure-activity relationship (QSAR) tool was studied for modeling the EC₅₀ of anionic surfactants on Daphnia magna based on the molecular descriptors. The best model (R² = 0.901 and F = 118.077, p<0.01) included 3 variables of the number of carbons, hydrogens, and the octanol-water partition coefficient logarithm. The main contribution to the toxicity was the octanol-water partition coefficient logarithm descriptor that had a negative effect on the toxicity of surfactants. The QSAR approach exhibited good results in predicting anionic surfactants EC₅₀, which allows the building of a simple, valid, and interpretable model that can be utilized as potential tools for rapidly predicting the lnEC50 of new or untested anionic surfactants to Daphnia magna.