Screening of hyperaccumulator plants tolerant to drought and salinity and its medicinal value evaluation for ecological reconstruction of copper silver tailings in Northwest China

The heavy metal pollution in soil caused by mining area development is a global problem. In order to screen the ecological restoration plants of copper silver tailings in arid and high saline alkali areas, and evaluate their economic value, nine kinds of plants naturally growing in the northwest copper silver tailings pond were selected, the enrichment and transfer characteristics of eight heavy metals by this plants was analyzed, and potential health risks for humans of plants were focused. The results showed that the heavy metals such as Cd, As, Cu, Hg and Ag are all from the open-air accumulation of tailings slag. Translocation factors of Cu, Ni and Cr by C. tragacanthoides are 2.1205, 53.1548 and 13.7622, bioconcentration factor of Cu, Ni and Cr by C. tragacanthoides are 1.8888, 7.1979, 7.4653, C. tragacanthoides is the hyperaccumulator for Cu, Ni and Cr. Hazard index in roots of S. collina, C. virgata and A. splendens to adults is more than 1, it has a potential non-cancer effects for more than half of adults, and for over 86.23% of children. Ag, Cr and As contribute the best to HI, and the cumulative contribution rate of the three elements can reach 85.59% to 96.39%. It is necessary to improve the treatment of tail slag to reduce environmental pollution, C. tragacanthoides can be considered as heavy metal remediation plants in arid and high saline copper tailing areas, but there is no medicinal value for these plants as ecological reconstruction in tailings area.