The Impact of Coal Pollution on Soil Microbial Diversity and Community Structure

This study investigates the impact of coal pollution on soil physicochemical properties and microbial communities in two coal mining regions in Jiaozuo City, China. Sampling was conducted at the Jiulishan and Yanma mining areas in Jiaozuo, Henan Province, China. Prolonged coal mining activities in these areas have led to soil contamination from coal dust and mine water irrigation, with pollution depths reaching 30-40 cm. The samples included coal-contaminated soils (CCS, 1-20 m from the field head, with coal carbon content of 7.08-11.44%) and coal-free soils (CFS, 250 m from the field head, with 0% coal carbon content). Soil samples were collected from a depth of 5-15 cm to evaluate microbial and key soil properties, including available phosphorus (AP), total phosphorus (TP), coal carbon content (CC), pH, available nitrogen (AN), total nitrogen (TN), soil organic carbon (SOC), bulk density (BD), and moisture characteristics. Coal pollution significantly enhances the maximum effective water holding capacity(Mewc) and BD of the soil. Compared to CFS, CCS shows an increase in AP and AP/TP by 18.64 mu g/g and 1.6%, respectively, as well as increases in AN, TN and AN/TN by 66.68 mg/kg, 1.05 g/kg, and 1.73%, respectively. In contrast, SOC and SOC/TN significantly decrease by 1.207% and 10.593% (P < 0.05). The dominant taxa remain Actinobacteriota and Ascomycota, with bacterial diversity in CCS increasing by 0.16 units. Additionally, fungal abundance, phylogenetic diversity, and ASVs all significantly rise (P < 0.05). The number of bacterial and fungal edges in the CCS co-occurrence network increases by 730 and 107, respectively, indicating a higher average degree and modularity, which suggests a robust adaptive capacity to environmental changes. Microorganisms such as Anaerolineae, SBR1031, Streptosporangiales, and Chryseolinea thrive in coal-contaminated environments due to their efficient carbohydrate degradation capabilities. Furthermore, field capacity(FC) and pH are identified as the primary factors influencing microbial community structure. Coal pollution alters soil structure, enhances microbial diversity, and increases community complexity, impacting nutrient cycling and water retention.