Abstract:

The experiment is to explore the application characteristics and repair effects of phytoremediation technology in cadmium (Cd) contaminated soil. Taking the actual soil with different levels of Cd pollution as the target, the Salix×aureo-pendula was selected by cutting cultivation to compare the tolerance, enrichment, transfer ability and remediation efficiency of Salix×aureo-pendula in different Cd polluted soil. The results showed that with the increase of Cd pollution concentration, the bioconcentration coefficient (BCF) of the aboveground and underground parts of Salix×aureo-pendula increased, and the above-ground enrichment ability was higher than that of the underground, which was 3.56-7.28 times of that of the underground. When the growth conditions were the same, the BCF and Cd contents of the 2-year-old Salix×aureo-pendula were significantly higher than that of the 1-year-old, which was 1.66 times and 1.47 times of that of the 1-year-old. It can be seen that the cloned Salix×aureo-pendula has higher tolerance and accumulation ability to Cd, and the longer the growth time, the more Cd is absorbed from the soil. In both the Cd-contaminated soils, the clonal Salix×aureo-pendula tends to transport part of Cd to the shoots to alleviate the toxicity of Cd, and the aboveground parts have a larger Cd ‘capacity’ than the roots. The removal of Cd from the branches, leaves, stems and roots of the heavily polluted soil is 1.01, 1.34, 1.93 and 3.47 times of that of the moderately contaminated soil, respectively. Therefore, in the heavily Cd-contaminated soil, the clonal Salix×aureo-pendula can remove a higher amount of Cd, and has higher Cd extraction and accumulation ability. In summary, the clonal Salix×aureo-pendula has higher tolerance and accumulation ability, can remove higher amount of Cd in higher Cd contaminated soil, and has the ability to be applied to medium and heavy Cd contaminated soil.

Key words: Salix×aureo-pendula, cadmium, phytoremediation, biomass, enrichment