The pH-Dependent Toxic Effects of Benzophenone-3 on Aquatic Organisms

Benzophenone-3 (BP-3), a widely used ultraviolet filter in personal care products, has been extensively detected in aquatic environments and poses potential ecological risks. This study innovatively investigated the pH-dependent acute toxicity of BP-3 to three model aquatic organisms— Daphnia magna , Photobacterium phosphoreum , and Danio rerio —by determining the EC 50 and LC 50 values across a pH range of 5.0 to 9.0. Our results revealed that BP-3 exerted greater acute toxicity on all three tested aquatic organisms under acidic conditions (pH 5.0) than under alkaline conditions (pH 9.0). The increased toxicity with lower pH was attributed to the predominance of the more lipophilic molecular form of BP-3, emphasizing the significant influence of environmental pH on BP-3 toxicity. These findings provide essential toxicological data for assessing the ecological risks of BP-3 in diverse aquatic environments, highlighting the necessity of considering BP-3 concentration, environmental pH and exposed species in ecological risk assessments.