Accumulation of Potentially Toxic Trace Elements (PTEs) by Native Plant Species Growing in a Typical Gold Mining Area Located in the Northeast of Qinghai-Tibet Plateau

Abstract

Though gold mines provide significant economic benefits to local governments, mining causes soil pollution by potentially toxic trace elements (PTEs) in mining areas, especially in the Qinghai-Tibet Plateau. Screening of native plant species from mining areas is now an effective, inexpensive, and eco-friendly method for the remediation of PTEs in situ. In the present study, we conducted experiments to assess the accumulation of As, Cd, Pb, and Zn in 12 native plant species growing on a typical gold mining area in Qinghai-Tibet Plateau. Our results showed that rhizosphere soils have high soil organic matter content, high levels of As, and moderate levels of Cd. G. pylzowianum accumulated relatively higher As in its shoots and exhibited TF higher than 1 for As (4.65), Cd (1.87), and Pb (1.36). P. saundersiana had BCF-S higher than 1 for Cd (4.52) and Pb (1.70), whereas its TF was higher than 1 for As, Cd, Pb, and Zn. These plant species also exhibit strong tolerance to these PTEs. Furthermore, E. nutans accumulated low levels of As, Cd, Pb, and Zn in their shoots and exhibited TF values lower than 1 for the four PTEs. Therefore, G. pylzowianum could be used for the in situ phytoextraction of As, and P. saundersiana can be used as an effective plant for Cd and Pb phytoextraction. E. nutans is better suited for the phytostabilisation of multiple PTEs. Our study is of significant importance for introducing native plant species to remediate PTE-contaminated soils, particularly As and Cd, and has a good potential for developing PTE phytoremediation strategies at mining sites.