Aquatic Photooxidation of Organic Ultraviolet Flters and Their in vitro and in vivo Toxicity Assessments
DescriptionThe wide use of organic ultraviolet filters (OUVFs) as active ingredients in sunscreens has resulted in massive release (approximately 14,000 tons per year) of these chemicals into the ocean. The concentrations of OUVFs have been demonstrated to reach µg/L levels at beaches and in wastewater effluents. It has been reported that many OUVFs are endocrine-disrupting chemicals (EDCs). In addition, OUVFs are known to photodegrade under extreme conditions (e.g., UVC irradiation), forming photooxidation products (PPs) commonly with unknown properties. The increasing environmental levels and potential hazards of OUVFs suggest their potential impacts on coastal marine ecosystems, such as on animals inhabiting coral reefs. Mostin vivostudies on OUVFs were conducted using freshwater model fishes while toxicological data from marine species are limited. Under environmentally relevant conditions (e.g., solar UVA/B), the impact of photoreactions and PPs formation is even less studied. Importantly, the ecotoxicological risk assessments on OUVFs do not include their PPs nor do they consider photooxidation/sunlight as a potential exacerbating factor. These knowledge gaps might compromise the usefulness of environmental risk assessment and result in underestimation of the environmental hazards of OUVFs. This study will focus on 2 OUVFs, Benzophenone-3 (BP-3) and Octinoxate (EHMC), which are commonly used and detected in coastal water samples worldwide. The proposed research aims to provide novel scientific insights into the formation of BP-3/EHMCF-PPs under environmentally relevant conditions. We will test the hypothesis that these PPs have significant endocrine-disrupting (ED) potency using a cell-based bioassay and in a marine model fish. The photooxidation of BP-3/EHMC will be conducted using a UV/H2O2system that simulates the condition of solar radiation with free radicals. We will also conduct a time course-based screening forin vitroED effects in cases where PPs mixtures cause significant ED activity. Finally, we will use the marine medaka embryo and adult fish to test the ED effects caused by parent compounds and PPs mixtures with the toxic mechanisms elucidated using transcriptomics and histopathology. Combined, this photochemical and ecotoxicological study will comprehensively characterize the environmental risks of BP-3/EHMC and their PPs by investigating both the transformation and endocrine disruptive toxicity associated with photooxidation as a potential exacerbating factor.The results of this study will provide critical information for risk assessment of OUVFs and allow us to better protect marine ecosystems in OUVF-polluted areas around the world. This study will also promote the research on radical-enhanced photooxidation of emerging organic pollutants.
|Effective start/end date||1/01/22 → …|