Organic ultraviolet filters in Hainan coral reefs: Distribution, accumulation, and ecological risks

Organic ultraviolet filters (OUVFs) have been widely used as functional ingredients of sunscreen products and have entered into marine ecosystems, particularly in tropical areas where solar UV radiation is strong. These chemicals, with their potential toxicity and ecological risk, have raised widespread concern for the protection of the fragile marine ecosystem of coral reefs. In this study, fourteen OUVFs were analyzed among 24 coral species, together with their habitats including seawater and sediment from the coastal coral reef regions of Hainan Island, South China Sea. Surprisingly, all of fourteen OUVFs were detected in each sample, indicating the wide distribution of OUVFs among sites and samples. Among the fourteen OUVFs, benzophenone-3 (BP-3) and 4-methylbenzylidene camphor (4-MBC) were the most abundant, with concentrations ranging from 35.3 to 75.6 and 38.3 to 61.4 ng/L in seawater, from 13.2 to 25.9 and 7.0 to 17.4 ng/g dw in sediment, and from 4.5 to 21.3 and 4.4 to 19.7 ng/g dw in corals, respectively. Analysis of OUVFs in 24 coral species pointed that OUVFs accumulation in corals is morphology dependent: the highest concentration of OUVFs was identified in Galaxea fascicularis with abundant of polyps and tentacles while the lowest levels of OUVFs were found in Porites mayeri (smooth or lobed surface). In corals, we found that these OUVFs accumulated, depending on the coral species and the types of OUVFs. The ecological risk assessment further indicated that BP-3, 4-MBC and BP-8 had posed risks to corals. In addition, significantly higher concentrations of OUVFs were observed in Sanya (a seaside tourist resort) than in the other sites, suggesting that tourist activity and use of sunscreen products are the key to high inputs of sunscreen agents into marine ecosystem. Overall, our study demonstrates a potential risk role for OUVFs in coral protection in tropical areas where coral bleaching events occur.