Evolution Trends of Key As- and S-Transforming Microorganisms Under As and S Combined Pollution in Landfills

This study takes the typical hydrological zones of municipal solid waste landfills as the research object, focusing on two distinct scenarios: the leachate-saturated zone and leachate-unsaturated zone of landfills. Under the condition of high-concentration As and S combined pollution, and with temperature gradient control of 25 degree centigrade(low temperature), 35 degree centigrade (medium temperature), and 45 degree centigrade (high temperature), this study systematically investigates the redox coupling mechanism and interfacial migration law of As and S speciation transformation. Meanwhile, using metagenomic sequencing and enzyme activity determination techniques, the study analyzes the expression levels of key functional genes (e.g., plastic-degrading gene lip, sulfur-reducing gene dsrA) and characteristic enzymes (e.g., lipase, dissimilatory sulfite reductase) that regulate microplastic formation (such as plastic aging and cracking, microbial degradation and synthesis) and hydrogen sulfide release, so as to clarify the direct correlation mechanism among functional genes, enzyme activities, and pollutant transformation processes.