The Taiyuan formation limestone water in the Huaibei coalfield is not only the water source for coal mining, but also the water source for industry and agriculture in mining areas. Its hydrogeochemical characteristics and water quality are generally concerning. In this paper, conventional ion tests were carried out on the Taiyuan formation limestone water of 16 coal mines in the Sunan and Linhuan mining areas of the Huaibei coalfield. Piper trigram, Gibbs diagram and an ion scale coefficient map were used to analyze the hydrogeochemical characteristics of the Taiyuan formation limestone water. The water quality was evaluated in a fuzzy comprehensive manner. The results show that the main cation and anion contents in the Taiyuan formation limestone water were Na⁺ > Mg²⁺ > Ca²⁺ > K⁺, SO₄²⁻ > HCO₃⁻ > Cl⁻. There were differences in the hydrogeochemical types of the Taiyuan formation limestone water in the two mining areas; HCO₃-Na type water was dominant in the Sunan mining area and SO₄·Cl-Na type water was dominant in the Linhuan mining area. The chemical composition of the Taiyuan formation limestone water is mainly affected by the weathering of the rock and is related to the dissolution of the evaporated salt and the weathering of the silicate. The fuzzy comprehensive evaluation results show that the V-type water accounts for a large proportion of the Taiyuan formation limestone water in the study area and the water quality is poor. This study provides a basis for the development and utilization of the Taiyuan formation limestone water and water environmental protection in the future.

This study analyzed the content characteristics, ecological risks, vertical migration characteristics and sources of soil heavy metals (Cr, Ni, Cu, Zn, As, Cd and Pb) in affected areas of Luning Coal Mine. Results showed that the average contents of Cr, Pb, Cu, As and Cd exceeded the surface soil background values of Anhui Province, but the risk of soil ecological environment was low. Cd had the largest single factor pollution index, As followed, and Cd in 14 sampling points reached the warning limit, 95% of the samples were in moderate hazard, 5% of the samples were in strong hazard, but the potential ecological hazard index of many kind of heavy metals was 81.81~121.41, which was low ecological hazard. The difficulty of vertical migration of heavy metals in soil was from easy to difficult: Cr>Ni&Cu>As>Zn>Cd&Pb; Cu, Zn and Pb were related to automobile exhaust emissions and transportation dust, Cd and Ni were mainly caused by natural geological processes, leaching of coal gangue hill and the discharge of industrial pollutants, As was mainly caused by agricultural activities, and Cr was closely related to coal combustion.

This study aimed to assess the heavy metal (Mn, Ni, Cu, Zn, Sr, Cd, Pb, and Cr) pollution characteristics, sources, and human health risks in shallow groundwater in the impact zones of urban and rural semi-intensive poultry farms in Suzhou City. Ordinary kriging interpolation showed that poultry farming contributed substantially to the pollution of shallow groundwater by Mn, Zn, and Cu. Positive matrix factorization was applied to identify the sources of heavy metals, and the health risks were assessed based on the hazard index and carcinogenic risks of the various sources. Heavy metal enrichment was closely related to anthropogenic activities. In addition, four sources were identified: poultry manure (29.33%), natural source (27.94%), industrial activities (22.29%), and poultry wastewater (20.48%). The main exposure route of carcinogenic and non-carcinogenic risks to adults and children was oral ingestion. The non-carcinogenic risk of oral ingestion in children was higher than that in adults; the carcinogenic risk was higher in adults than in children. Poultry manure (42.0%) was considered the largest contributor to non-carcinogenic risk, followed by poultry wastewater (21%), industrial activities (20%), and natural sources (17%). Industrial activity (44%) was the primary contributor to carcinogenic risk, followed by poultry wastewater (25%), poultry manure (19%), and natural sources (12%).

Long-term mining activities have changed the hydrogeochemical evolution process of groundwater and threatened the safe use of groundwater. By using the methods of hydrochemistry and multivariate statistical analysis, this study determined the hydrogeochemical evolution mechanism affecting the quality of karst groundwater by analyzing the conventional hydrochemistry data of the karst groundwater of the Carboniferous Taiyuan Formation in Hengyuan Coal Mine in the recent 12 years. The results show that, under the disturbance of mining, the quality of karst groundwater in Taiyuan Formation is poor, mainly because the contents of Na⁺+K⁺ and SO₄²⁻ are too high to allow usage as drinking water. The reason for the high content of SO₄²⁻ in karst groundwater lies in the dissolution of gypsum and the oxidation of pyrite, and the high content of Na⁺+K⁺ lies in the cation exchange. Influenced by the stratum grouting, the circulation of karst groundwater is improved, the cation exchange is weakened, and the desulfurization is enhanced. In the future, it is predicted that the hydrochemical type of karst groundwater in Taiyuan Formation in the study area will evolve from SO₄-Ca·Mg type to HCO₃-Ca Mg type.