Reactions of clofibric acid with oxidative and reductive radicals-Products, mechanisms, efficiency and toxic effects

The degradation of clofibric acid induced by hydroxyl radical, hydrated electron and O-2(-center dot)/HO2 center dot reactive species was studied in aqueous solutions. Clofibric acid was decomposed more effectively by hydroxyl radical than by hydrated electron or O-2(-center dot)/HO2 center dot. Various hydroxylated, dechlorinated and fragmentation products have been identified and quantified. A new LC-MS method was developed based on O-18 isotope labeling to follow the formation of hydroxylated derivatives of clofibric acid. Possible degradation pathways have been proposed. The overall degradation was monitored by determination of sum parameters like COD, TOC and AOX. It was found that the organic chlorine degrades very effectively prior to complete mineralization. After the treatment no toxic effect was found according to Vibrio fischeri tests. However, at early stages some of the reaction products were more harmful than clofibric acid. (C) 2014 Elsevier Ltd. All rights reserved.