Benzophenone-3 and ethylhexyl methoxycinnamate UV filters in freshwater environments: A Laurentian Great Lakes data needs analysis for assessing environmental risk

•Many BP-3 and EHMC effect threshold values are above solubility limits•Understanding consumer sunscreen habits is needed to estimate exposure potential•Environmental source attribution study is needed•Environmental partitioning study needed to understand risk of UV filters Ultraviolet radiation (UVR) exposure is a health concern due to its ability to cause sunburn, photoaging, and skin cancer. Sun protection products (e.g., sunscreens) comprising of chemical ingredients called UV filters have been developed to protect human skin against harmful UVR. Usage of sunscreen often involves outdoor activities and the release of UV filters (e,g, benzophenone-3 (BP-3) or ethylhexyl methoxycinnamate (EHMC)) into the aquatic environment which has resulted in regulatory restrictions. Much of the existing research has focused on UV filters in the marine ecosystems, while less research has addressed impacts of UV filters to freshwater ecosystems. This paper presents the results of a data gap analysis for environmental risk assessment of BP-3 and EHMC in freshwater environments. The Laurentian Great Lakes are a significant water resource containing 84% of North America's fresh surface water. As such, it is an ideal target environment for this data needs analysis. A literature review of the available freshwater ecotoxicology and occurrence data for BP-3 and EHMC was performed. There is a relatively complete hazard data set for each UV filter; however, many threshold values were found to exceed the water solubility limit of the test substances and were not verified using analytical methodologies. No Great Lakes sampling measurements were found. In the absence of measured data, a screening exposure assessment was conducted for three Great Lakes beaches. This exercise illustrated key data gaps needed to conduct a more representative exposure assessment, such as environmental partitioning potential and consumer sunscreen usage amounts. This analysis is a starting point to better assess the potential adverse effects of UV filters on the Great Lakes ecosystem. As new data, assumptions, methods, and models are developed, environmental risk assessments should be reiterated to improve understanding and better inform decision-making to protect both human health and the environment. [Display omitted]