Pollution characteristics and risk assessment of steroid hormones in Qinzhou Bay, South China Sea: A result of multi-source synergistic effects

Through integrated land-sea monitoring and investigation, the pollution characteristics and ecological risks of steroid hormones in Qinzhou Bay area were systematically assessed, and a source analysis was conducted. A total of 24 and 21 types of steroid hormones were detected in seawater and sediments, respectively, with concentration ranges of 0.05 ng/L (MT) to 3.90 ng/L (E3) in seawater, and 0.02 ng/g (MT) to 2.32 ng/g (P) in sediments(dry weight). In the five artificially divided regions, the average concentration trend of steroid hormone in seawater was Maowei Sea aquaculture area > Longmen aquaculture area > Qinzhou Bay aquaculture area > Industrial Area > control area, and the average concentration trend of steroid hormone in sediment was industrial area > Maowei Sea aquaculture area > control area > Qinzhou Bay aquaculture area > Longmen aquaculture area. The above distribution characteristics could be attributed to the physicochemical properties of steroid hormones, regional environmental conditions and human factors. Source analysis indicated that the occurrence of steroid hormones in Qinzhou Bay mainly resulted from the combined influences of mariculture, land-based inputs, and multiple sources within the industrial area. In the Maowei Sea aquaculture area, steroid hormones were negatively correlated with salinity and pH, but positively correlated with other environmental parameters, further confirming the significant impact of terrestrial inputs. Ecological risk assessment revealed that MT and EE2 were classified as posing a high-risk level in this region. This study provided important references for relevant authorities in the management of steroid hormone pollution and ecological risk assessment in Qinzhou Bay.