Occurrence and fate of benzophenone-type UV filters in aquatic environments: a review†
Benzophenone-type ultraviolet filters (BP-type UV filters or BPs) are extensively used in a diverse array of personal care products (PCPs), including sunscreens and many cosmetics. The widespread use of BPs has resulted in their release into aquatic environments, directly via human recreational activities and indirectly via effluents of wastewater treatment plants (WWTPs). BPs have been reported to elicit endocrine disrupting properties. This paper reviews the knowledge regarding the physicochemical properties, occurrence, fate and behavior of BPs in aquatic environments. Despite their high removal efficiency in WWTPs, BPs are consistently detected in effluents at relatively low concentrations. Although BPs readily undergo biodegradation and indirect photolysis, they are considered to be pseudo-persistent in surface waters and benthic sediments, a result of the usage of BP-containing products and their continuous release into the environment. In the BP family, benzophenone-3 (BP-3) is the dominant species in the environment, possibly a reflection of the composition of BPs in commercial and industrial products. BPs can react rapidly with aqueous chlorine, forming halogenated by-products. Knowledge on the occurrence, fate and toxicity of these halogenated by-products is scarce and thus further investigation is needed.