Effects of phytoremediation on the structure and function of bacterial communities in tungsten tailings

Tungsten mining produces a large amount of tailings, which causes serious problems to the environment and resources, and phytoremediation is a potentially effective strategy, but there is a lack of research on tungsten tailings-suitable plants and related microbial communities. In this study, we selected six plant species, including Trifolium repens, Cynanchum Paniculatum kitag, Medicago sativa, Festuca elata, Perennial ryegrass and Brassica napus, to carry out tungsten tailings vegetation restoration experiments, and utilized high-throughput sequencing technology to study the changes in microbial community structure and function and analyze the driving factors of the plant colonization, Concurrently, pioneer plants with potential for tungsten tailings remediation were screened based on soil multifunctional indices. The results showed that plant colonization significantly reduced the pH (1.69%—11.46%) and salinity (0.42%—39.30%) of the tailings, increased the content of organic matter (42.12%—87.86%), and significantly changed the enzyme activities (urease and acid phosphatase activities were increased, and β-glucosidase and alkaline phosphatase activities were decreased). Microbial abundance and diversity in the tailings were significantly higher, ranging from 38.54%—81.18%, respectively and 23.31%—40.14%, respectively. Altering the structure of bacterial dominant flora increased the relative abundance of beneficial bacteria such as Acidobacteriota, Cyanobacteria and Gemmatimonadota. FAPROTAX functional prediction indicated that the plantation group was enriched for metabolic pathways related to carbon, nitrogen, and sulfur cycles. Redundancy analysis (RDA) and variance decomposition analysis (VPA) indicated that nutrients such as effective phosphorus (AP), organic matter (OM), and effective nitrogen (AN) were the main factors driving changes in microbial communities (32.48% explained), followed by heavy metals (14.97%) and chemical properties (1.39%). Based on the soil multifunctionality index, the Festuca elata (GYM) performed best in early remediation and has a promising application.