Aquatic environmental photochemical behavior of organic sunscreens

Organic sunscreens are emerging pollutants frequently detected in aqueous environments, and draw increasing concerns due to their potential ecological risks. Photochemical transformation is an important transformation pathway of widely used organic sunscreens in surface waters, and can influence their environmental fate and ecological risk. In this paper, the current research progresses on the aqueous environmental photochemical behavior of organic sunscreens are reviewed. The direct, self-sensitized and indirect photodegradation kinetics of organic sunscreens is introduced. The effects of pH and water constituents on the photodegradation kinetics are highlighted. Photochemical transformation products, pathways of some widely used sunscreens are summarized, and photodegradation mechanisms are discussed. Furthermore, a brief overview on the toxicity, and especially photoinduced toxicities of organic sunscreens, is included. Finally, further studies on aqueous photochemical behavior of organic sunscreens and other emerging pollutants are proposed.