Remediation Potential of Three Dwarf Bamboos on Farmland Soils Contaminated with Mixed Heavy Metals

Abstract

A two-year field experiment was carried out in a Cu-Zn-Cd-Pb-contaminated field with Sasa auricoma, Indocalamus tessellatus, and Shibataea chinensis Nakai to investigate their growth and accumulation characteristics. Based on changes in heavy metal content in the soil, we compared their phytoremediation potentials for the combined pollution of heavy metals. After two years of planting, S. auricoma showed the best tolerance to soil contaminated by heavy metals, with the number of plants being 63.8 times that at the time of planting. For each bamboo type, heavy metals were most concentrated in the root, with the best enrichment ability of Cd and worst ability of Pb. The bioconcentration factor of Cd in the roots was far greater than 1 for all three species, with 17.68 for S. auricoma and 14.63 for I. tessellatus. The accumulation of heavy metals was mainly concentrated in the roots and rhizomes, and the accumulations of Cu, Zn, and Cd in S. auricoma were 157.14, 363.3, and 7.18 g·hm-2, respectively, which were higher than those of I. tessellatus and S. chinensis Nakai. Compared with that before planting, the content of heavy metals in the non-rhizosphere soil decreased after two years of planting, among which Cd content decreased the most, from 39.6%-40.4%. In addition, the contents of Cu, Zn, and Cd in rhizosphere soil of S. auricoma and S. chinensis Nakai were significantly lower than those in non-rhizosphere soil (P<0.05). The results showed that the three species had strong accumulation ability of Cd and could be further studied as Cd-repaired plants. The growth condition and content and accumulation of heavy metals in S. auricoma were excellent among the dwarf bamboos, which showed the highest phytoremediation potential.