Vanadium accumulation mode of Heteropogon contortus and its driving factors in Majiatian tailing reservoir in Panzhihua, Southwestern China

Abstract

Native plants in metal pollution sites have great potentials for mine rehabilitation. In the presented work, we investigated Vanadium (V) concentrations of soils and plants (Heteropogon contortus) in Majiatian V-Ti magnetite tailing reservoir in Panzhihua, Southwestern China. The objectives were to explore the V accumulation mode of H. contortus and its driving factors, as well as the phytoremediation potential of H. contortus. As the results, H. contortus accumulated 37.53 mg/kg and 8.69 mg/kg of V in root and aerial part, respectively. With the increase of rehabilitation age, root V concentrations decreased, while aerial part V concentrations remained constant. The significant negative correlations between root V and soil V, acid-soluble V (V_HAc) (P < 0.05) indicated that increasing soil V and V_HAc concentrations drove the V accumulation mode of H. contortus. Soil properties had a little influence on the V accumulation mode of H. contortus. Therefore, H. contortus might be not the suitable plant extractant to remove V from mine tailing for its lower V accumulation capacity. On the other hand, it can tolerate high V stress through elimination and detoxification/isolation V. Furthermore, the settlement of H. contortus increased the content of soil organic matter and might thus improve the soil quality. The cover of H. contortus is also beneficial to reduce the dispersion of the tailings and prevent contaminating surrounding soil. Therefor it showed a great potential to serve as a pioneer plant in the remediation of V-rich tailing reservoirs and other V-contaminated sites with similar poor soil condition.

Keywords: Mine rehabilitation ··phytostabilization ··pioneer plant ··heavy metals ··panzhihua.