The seasonal and spatial changes in the chemical composition of the water in abandoned mine drainages and rivers in Yudong River area in the years of 2017–2018 were analyzed. The effects of mine water drainage on the seasonality and physicochemical properties of the river water after mine closure were evaluated, and the feasibility of irrigation using river water and the degree of pollution to farmland were assessed using the Water Quality Standard for Farmland Irrigation. The results show that the mine water has low pH value (< 3.5–4) and high levels of total hardness, SO₄²⁻, Fe, Al, and Zn. In addition, the pH of the mine water is negatively correlated with the presence of other metal ions. The correlation coefficient between the chemical oxygen demand (COD) and Fe reached 0.989. While the pollution levels of Pinglu and Baishui rivers were low, the confluence region of the two rivers was seriously polluted. However, only the levels of Fe and Cd slightly exceeded the Surface Water Environmental Quality Standard after the confluence of Yudong and Chongan rivers. Overall, the heavy pollution type of the confluent river is consistent with mine water pollution. The water quality is slightly better in the dry season compared than in the high-water period. Sulfate and Fe content decreased by 39 and 16 mg/L, respectively, and Cd content decreased two-fold. Despite these findings, this study shows that from 2017 to 2018, the pH and Cd content of the rivers at the confluence exceeded the irrigation limit and the water quality continued to deteriorate, which may pose a soil contamination risk. Long-term use of the river for irrigation water may cause toxic elements such as Cd, Fe, Mn, SO₄²⁻, Al, and F^- to enter the food chain, thereby endangering the life and health of villagers in Yudong River area.

This work investigated the spatial profile and source analysis of polycyclic aromatic hydrocarbons (PAHs) in soil that surrounds coal-fired power plants in Xuzhou, China. High-throughput sequencing was employed to investigate the composition and structure of soil bacterial communities. The total concentration of 15 PAHs in the surface soils ranged from 164.87 to 3494.81 μg/kg dry weight. The spatial profile of PAHs was site-specific with a concentration of 1400.09–3494.81 μg/kg in Yaozhuang. Based on the qualitative and principal component analysis results, coal burning and vehicle emission were found to be the main sources of PAHs in the surface soils. The phylogenetic analysis revealed differences in bacterial community compositions among different sampling sites. Proteobacteria was the most abundant phylum, while Acidobacteria was the second most abundant. The orders of Campylobacterales, Desulfobacterales and Hydrogenophilales had the most significant differences in relative abundance among the sampling sites. The redundancy analysis revealed that the differences in bacterial communities could be explained by the organic matter content. They could also be explicated by the acenaphthene concentration with longer arrows. Furthermore, OTUs of Proteobacteria phylum plotted around particular samples were confirmed to have a different composition of Proteobacteria phylum among the sample sites. Evaluating the relationship between soil PAHs concentration and bacterial community composition may provide useful information for the remediation of PAH contaminated sites.