Characteristics and Transformation Mechanism of Nitrogen Pollution in Coal Mine Water

Nitrogen is recognized as a widely distributed groundwater pollutant around the world, the environmental and drinking water safety issues caused by it have received widespread attention. Previous studies have extensively investigated the distribution characteristics and transformation mechanisms, but mine water differs from conventional groundwater due to both natural processes and human activities. Given limited comprehension regarding nitrogen pollution characteristics and transformation mechanisms in mine water, this study chose a mining area in Shanxi Province as the research object, Multiple sets of water samples were collected such as roof fracture water. Through chemical analysis, three-dimensional fluorescence spectroscopy (3DEEM), 16s rRNA high-throughput sequencing, Piper trilinear diagram method, and ion ratio coefficient method, we explored the migration-transformation mechanism of nitrogen pollutants in mining areas. The results showed that nitrogen pollution was generally present in the study area, Ammonia nitrogen in 83% of water samples exceeded the standard. The migration-transformation of nitrogen was mainly affected by water–rock reactions, microbial actions, human-induced factors and so on, while conventional treatment methods used at mine water treatment plants had little effect on removing nitrogen pollutants. The results provide scientific support for the comprehensive utilization of mine water resources in western China.