National-scale down-the-drain environmental risk assessment of oxybenzone in the United States


Organic ultraviolet (UV) filters are used in cosmetic and personal care products (CPCPs) and over-the-counter (OTC) sunscreens, due to their ability to absorb solar radiation. OTC and CPCP ingredients are washed down-the-drain and can then enter freshwaters that receive wastewater treatment plant (WWTP) effluents. This paper presents a freshwater environmental safety assessment of a key UV filter, oxybenzone, used in OTC sunscreens and CPCPs in the United States. Exposure was characterized using iSTREEMĀ®, a spatially resolved aquatic exposure model developed for chemicals disposed of down-the-drain. It provides a comprehensive exposure assessment of oxybenzone concentrations in U.S. receiving waters through predicted environmental concentration (PEC) distributions representative of conditions across the region. A review of available hazard data was used to derive a predicted no-effect concentration (PNEC) using aquatic toxicity data and assessment factors. A safety assessment was conducted by comparing the PEC distribution to the PNEC. The results indicate that oxybenzone is of low concern and there is a significant margin of safety; even the 90th percentile PEC is two orders of magnitude below the PNEC. These results are instrumental in demonstrating the environmental safety of key organic UV filters in the U.S. freshwater environment and will help prioritize future work. This article is protected by copyright. All rights reserved.

Authors: Emily E Burns, Susan A Csiszar, Kyle Roush, Iain A Davies
; Full Source: Integrated environmental assessment and management 2021 Apr 29. doi: 10.1002/ieam.4430.