Trace analysis of benzophenone-type UV filters in water and their effects on human estrogen and androgen receptors.

To carry out risk assessments of benzophenone-type UV filters (BPs), fast and accurate analytical methods are crucial to determine and monitor levels in the environment. This study presents an LC-MS/MS method that requires minimal sample preparation and yet can identify 10 different BPs in environmental samples such as surface or wastewater resulting in a LOQ range from 2 to 1060 ng/L. The method suitability was tested through environmental monitoring, which showed that, BP-4 is the most abundant derivative found in the surface waters of Germany, India, South Africa and Vietnam. BP-4 levels correlate with the WWTP effluent fraction of the respective river for selected samples in Germany. Peak values of 171 ng/L for 4-hydroxybenzophenone (4-OH-BP), as measured in Vietnamese surface water, already exceed the PNEC value of 80 ng/L, elevating 4-OH-BP to the status of a new pollutant that needs more frequent monitoring. Moreover, this study reveals that during biodegradation of benzophenone in river water, the transformation product 4-OH-BP is formed which contain structural alerts for estrogenic activity. By using yeast-based reporter gene assays, this study provides bio-equivalents of 9 BPs, 4-OH-BP, 2,3,4-tri-OH-BP, 4-cresol and benzoate and complements the existing structure-activities relationships of BPs and their degradation products.

Primary and ultimate degradation of benzophenone-type UV filters under different environmental conditions and the underlying structure-biodegradability relationships.

Ten common benzophenone-based UV filters (BPs), sharing the same basic structure and differing only in their substituents, were investigated with respect to their primary and ultimate biodegradability. This study was carried out in order to gain deeper insights into the relationship between structure and biodegradability. The primary biodegradation of the selected BPs was studied in river water at environmentally relevant concentrations (1 µg/L) while varying specific, crucial environmental conditions (aerobic, suboxic, supplementation of nutrients). For this purpose, both batch and column degradation tests were performed, which allowed a systematic study of the effects. Subsequently, the ultimate biodegradation, i.e. the potential to achieve full mineralization of BPs, was examined according to OECD guideline 301 F. The results indicate that mineralization is limited to derivatives in which both aromatic rings contain substituents. This hypothesis was supported by docking simulations showing systematic differences in the orientation of BPs within the active site of the cytochrome P450 enzyme. These differences in orientation correspond to the substitution pattern of the BPs. This study provides valuable insights for assessing the environmental hazards of this class of trace organic compounds.

Structure-related endocrine-disrupting potential of environmental transformation products of benzophenone-type UV filters: A review.

Benzophenone-type UV filters (BPs) represent a very diverse group of chemicals that are used across a range of industrial sectors around the world. They are found within different environmental compartments (e.g. surface water, groundwater, wastewater, sediments and biota) at concentrations ranging from ng/L to mg/L. Some are known as endocrine disruptors and are currently within the scope of international regulations. A structural alert for high potential of endocrine disrupting activity was assigned to 11 BP derivatives. Due to the widespread use, distribution and disruptive effects of some BPs, knowledge of their elimination pathways is required. This review demonstrates that biodegradation and photolytic decomposition are the major elimination processes for BP-type UV filters in the environment. Under aerobic conditions, transformation pathways have only been reported for BP, BP-3 and BP-4, which are also the most common derivatives. Primary biodegradation mainly results in the formation of hydroxylated BPs, which exhibit a structure-related increase in endocrine activity when compared to their parent substances. By combining 76 literature-based transformation products (TPs) with in silico results relating to their receptor activity, it is demonstrated that 32 TPs may retain activity and that further knowledge of the degradation of BPs in the environment is needed.