Vanadium Influenced Soil Micro-Ecological Variation in Farmlands Surrounding Iron Tailing in Southwest China

Long-term vanadium titanomagnetite (VTM) mining in Panzhihua, China leads to serious metal pollution in the adjacent agricultural soil, which causes great environmental and health concerns. In this study, the titanium-magnetite tailing influenced farmlands soils of the Panzhihua area with different plants (grape, mongo, tobacco, corn) were collected to investigate the metals (V, Fe, Mn, Ti) contamination and the related microbial response. The studied soils presented average vanadium (V) at 233.57 mg/kg. The farmland soils presented an increased available Fe and Mn compared to the unplanted soil, and soils with different plants showed varied available metals except for Mn. Tobacco planting contributed to the immobilization of V and Ti. The planted soils showed 2.33-3.11 times, 9.50-37.89 times, 0.11-1.20 times, and 5.43-26.46 times higher activities of urease, dehydrogenase, sucrase, and acid phosphatase than the unplanted ones, respectively. Nocardioides and Sphingomonas were found conduced to the enrichment of metal resistance genes ( van ) and integration genes ( intlI ), which were also significantly positively correlated with available V, Ti, Mn, and acid phosphatase activity. Such knowledge reveals the impact of VTM mining on the agricultural ecological environment, which have potential value for the risk evaluation of such influenced lands.