Occurrence, bioaccumulation and ecological risk of organic ultraviolet absorbers in multiple coastal and offshore coral communities of the South China Sea

The occurrence of organic ultraviolet absorbers (OUVAs) in coral reef regions has aroused widespread concern. This study focused on the occurrence, distribution, bioaccumulation and ecological risk of ten OUVAs in both coastal and offshore coral reef regions in the South China Sea. While the sigma 10OUVAs was 85 % lower in the offshore seawater (15.1 ng/L) than in the coastal seawater (102.1 ng/L), the sigma 10OUVAs was 21 % lower in the offshore corals (1.82 mu g/g dry weight (dw)) than in the coastal corals (2.31 mu g/g dw). This difference was speculated to relate to the high intensity of human activities in the coastal regions. Moreover, the offshore corals showed higher bioaccumulative ca-pability toward OUVAs (log bioaccumulation factors (BAFs): 1.22-5.07) than the coastal corals (log BAFs: 0.17-4.38), which was presumably the influence of varied physiological status under different environmental conditions. The re-sults of the ecological risk assessment showed that BP-3 resulted in 73 % of coastal corals and 20 % of offshore corals at a risk of bleaching. Therefore, the usage and discharge of BP-3 should be managed and controlled by the countries ad-jacent to the South China Sea for the protection of coral reefs.

Automated summary

This study investigated the occurrence, distribution, bioaccumulation and ecological risk of organic ultraviolet absorbers (OUVAs) in coral reef regions in the South China Sea. The results showed that OUVAs were lower in offshore seawater and corals compared to coastal areas, possibly due to higher human activities. Additionally, offshore corals exhibited higher bioaccumulation capability of OUVAs and BP-3 posed bleaching risks to both coastal and offshore corals. The management and control of BP-3 usage and discharge is crucial for coral reef protection in the South China Sea.