title: Assessment and modeling of the novel toxicity data set of phenols to Chlorella vulgaris.
abstract: This study provides for the first time the 96 h toxicity of 30 phenols to Chlorella vulgaris. Analysis of the novel data set revealed that the algal toxicity of polar narcotics and respiratory uncouplers was correlated strongly to the pH corrected hydrophobicity parameter, Log D, demonstrating the importance of ionization in the C. vulgaris test system. Compounds expected to act by more reactive mechanisms were shown to have toxicity in excess of that predicted by Log D and were successfully modelled using the activation energy index (AEI). Three global quantitative structure-activity relationships (QSARs) were constructed using the C. vulgaris data set and validated externally using a data set retrieved from literature comprising the toxicity of 58 compounds to freshwater alga Pseudokirchneriella subcapitata. Results revealed that the response-surface model was highly interpretable and provided acceptable predictions for polar narcotics and respiratory uncouplers, though it lacked the reliability to predict the toxicity of reactive phenols. In two other externally validated QSAR models, a WHIM (Weighted Holistic Invariant Molecular) descriptor, namely, Tm (T total size index/weighted by atomic masses), revealed promising results that could be used to predict algal toxicity of compounds other than phenols such as anilines.
authors: Boğaziçi University, Institute of Environmental Sciences, Istanbul, Turkey. doga.erturk@boun.edu.tr
authors: M Doğa
authors: MD
authors: Ertürk
authors: Melek Türker
authors: MT
authors: Saçan
mesh_terms: D048408:Chlorella vulgaris / Q000187:drug effects*; D057927:Hydrophobic and Hydrophilic Interactions; D008962:Models, Theoretical; D010636:Phenols / Q000737:chemistry / Q000633:toxicity*; D021281:Quantitative Structure-Activity Relationship; D015203:Reproducibility of Results; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D010636:Phenols; D014874:Water Pollutants, Chemical