A comprehensive analysis of storage impact on toxicity assessment of ozonated effluents.

Neglecting the time intervals between sampling and biological testing can lead to misinterpretation of the hazards associated with advanced oxidation processes when assessed through bioassays. This study investigates changes in the non-specific toxicity of ozonated aromatic compounds and analyzes the factors such as temperature and light exposure influencing these changes during sample storage. The findings reveal a significant decrease in biotoxicity of ozonated effluents, ranging from 41 % to 83 %, within the first four days of storage at 22 °C under natural light exposure.

Redox-directed identification of toxic transformation products during ozonation of aromatics.

The toxicity assessment of transformation products (TPs) formed in oxidative water treatment is crucial but challenging because of their low concentration, structural diversity, and mixture complexity. Here, this study developed a novel redox-directed approach for identification of toxic TPs without the individual toxicity and concentration information. This approach based on sodium borohydride reduction comprised an integrated process of toxicological evaluation, fluorescence excitation-emission matrix characterization, high-resolution mass spectrometry detection, followed by ecological toxicity assessment of identified TPs.