Pb Tolerance and Accumulation of Pollutant-Remediation Plants

Based on a literature search, 12 species in the families of Gramineae, Leguminosae, Compositae and Solanaceae, that are phytoremediation plants capable of decontaminating Pb polluted soil, were studied for their Pb tolerance and accumulation capacities. The plants were subjected to Pb stress at varied concentrations (i.e., 0, 500, 1 000, 1 500 and 2 000 mg·kg^-1) in an indoor pot experimentation. The root length, height, biomass, above-and under-ground Pb contents were determined to compare the Pb tolerance and accumulation of the plants. The results showed that, as the Pb concentration in soil increased, all plants decreased on biomass and increased Pb content in the order of roots, stems, and leaves. A comprehensive evaluation suggested that Campsis grandiflora, Lolium perenne and Poa pratensis had the potentials for use of remediating the soil pollution in lead and zinc mining areas. Among the tested, 6 plants showed a bioconcentration factor (BCF) greater than 1 at the Pb contamination level of 1 500 mg·kg^-1:Poa annuaat 3.46, Aster ageratoides at 3.34, L. perenne at 2.32, Cynodon dactylon at 1.78, Rudbeckia hirta at 1.72, and Capsicum annuum 276 at 1.26. And, three varieties had a translocation factor (TF) greater than 1:C. annuum 276 at 1.36, R. hirta at 1.30, and Medicago sativa at 1.23. Taking BCF, TF and repair potential index together into consideration, R. hirta appeared to be the choice species for Pb remediation on polluted soil with a displayed capability of accumulating 2.576 mg Pb per plant in above-ground parts from a soil containing Pb 1 025 mg·kg^-1.