Steroid estrogens have received worldwide attention and given rise to great challenges of aquatic ecosystems security, posing potential adverse effects on aquatic organisms and human health even at low levels (ng/L). The present study focused on understanding the mobility and abiotic transformation of estrone (E1) and estrone-3-sulfate (E1-3S) over spatial and time scales during soil transport. Column transport experiments showed that the migration capacity of E1-3S was far stronger than E1 in soil. The calculated groundwater ubiquity score and leachability index values also indicated the high leaching mobility of E1-3S. The hydrolysis of E1-3S and abiotic transformation into estradiol and estriol was observed in the sterilized soil. Furthermore, possible transformation products (e.g., SE239, E2378, E1 dimer538, E1-E2 dimer541) of E1 and E1-3S in soil were analyzed and identified after the column transport experiments. The estrogenic activity was estimated by 17β-estradiol equivalency values during the transport process in aqueous and soil phases. Additionally, the potential leaching transport to groundwater of E1-3S requires further critical concern.

Animal husbandry is the second largest source of steroid estrogen (SE) pollutants in the environment, and it is significant to investigate the occurrence and fate of SEs discharged from concentrated animal feeding operations. In this research, with a Chinese typical concentrated dairy farm as the object, the concentrations of SEs (E1, 17α-E2, 17β-E2, E3, and E1-S3) in slurry, lagoon water, and slurry-irrigated soil samples in summer, autumn, and winter were determined. The total concentrations of SEs (mainly E1, 17α-E2, and 17β-E2) in slurry were very high in the range of 263.1-2475.08 ng·L-1. In the lagoon water, the removal efficiencies of the aerobic tank could reach up to 89.53%, with significant fluctuation in different seasons. In the slurry-irrigated soil, the maximum concentrations of SEs in the topsoil and subsoil were 21.54 ng·g-1 to 6.82 g·g-1, respectively. Most of the SEs tended to transport downward and accumulate in the soil accompanied with the complex mutual conversion. Correlations and hierarchical clustering analysis showed a variety of intertransformation among SEs, and the concentrations of SEs were correlated with various physicochemical indexes, such as TN and NO3--N of the slurry, chemical oxygen demand of the lagoon water, and the heavy metals of soil. In addition, 17β-estradiol equivalency assessment and risk quotients indicated that the slurry irrigation and discharge of the lagoon water would cause potential estrogenic risks to the environment. Consequently, reasonable slurry irrigation and lagoon water discharge are essential to efficiently control SE pollution in the environment.