Study on the spatiotemporal distribution characteristics and risk assessment of steroid hormones in Qinjiang River of Beibu Gulf, China: Human activities play a significant role.

27 sampling sites were set up to study the concentration levels, seasonal and spatial distribution characteristics of typical steroid hormones in Qinjiang River, and to assess their ecological risks. 33 Steroid hormone compounds were detected during both the wet and dry seasons, with concentration ranges of ND ∼ 13.25 ng/L (α-E2) and ND ∼ 4.9 ng/L (1,4-AE), respectively. The total concentration of steroid hormones in Qinjiang River generally exhibited a trend of being higher in the upstream areas with less urbanization than in the downstream areas with more urbanization, increasing from the upstream to the midstream or downstream, and then decreasing towards the estuary. The investigation indicated that the spatial distribution of steroid hormone concentrations in the Qinjiang River basin closely matches the geographic locations of riparian anthropogenic activities, aquaculture, and livestock and poultry farming, with the high pollution areas lying within the intensive distribution zones of these activities. The ecological risk assessment indicated that β-E2 and 17-MT posed high ecological risks at certain sites in the region during both the wet and dry seasons. E1, E2, and E3 might lead to high estrogenic potency, and these compounds should be regarded as priority pollutants in the river. Relevant authorities should pay increased attention and enhance environmental management efforts around the Qinjiang River Basin to further mitigate the ecological risks posed by steroid hormones.