Lead accumulation and phytostabilization potential of dominant plant species growing in a lead–zinc mine tailing

Screening out plants that are hyper-tolerant to certain heavy metals plays a fundamental role in remediation of mine tailing. In this study, nine dominant plant species growing on lead–zinc mine tailing and their corresponding non-mining ecotypes were investigated for their potential phytostabilization of lead. Lead concentration in roots of these plants was higher than in shoots, and the highest concentrations of lead were found in Athyrium wardii: 15542 and 10720 mg kg⁻¹ in the early growth stage (May) and vigorous growth stage (August) respectively, which were 426 and 455 times higher than those of the non-mining ecotypes. Because of poor lead translocation ability, lead accumulation in roots reached as high as 42 mg per plant. Available lead in the rhizosphere soils of A. wardii was 310 mg kg⁻¹, which was 17 times higher than that of the non-rhizosphere soil. Lead concentrations of roots for the nine mining ecotypes were positively correlated with available lead in the rhizosphere soils, whereas a negative correlation was observed in the non-mining ecotypes. These results suggest that A. wardii was the most promising candidate among the tested species for lead accumulation in roots, and it could be used for phytostabilization in lead polluted soils.