龙葵(Solanum nigrum L.)野外场地规模Cd污染土壤修复试验

Field experiment on phytoremediation of cadmium contaminated soils using Solanum nigrum L.

镉（Cd）是我国重金属污染土壤中主要的污染元素之一。在污染土壤的修复措施中,植物修复是一种绿色技术,具有传统土壤治理方法所无法比拟的优点,也是现今国际环境修复的热点和前沿领域。本研究以龙葵为修复植物,进行了为期2年的野外场地规模Cd污染土壤植物修复预试验和试验研究。对修复前、后土壤Cd含量分析表明,土壤表层和亚表层Cd的去除作用明显。预试验和重复试验中,土壤表层Cd的平均减少率为6.3%和16.8%,亚表层各层Cd的减少幅度分别为50.6%和49.5%（20～40 cm）、73.5%和53.9%（40～60 cm）、80.7%或未检出（60～80 cm）。2组数据表明,在农田土壤条件下,龙葵植株可产生较大的生物量,从而提高对Cd的积累与运移能力;采用植物修复技术可实现轻、中度Cd污染土壤的修复,以实现农业生产的良性循环。

Cadmium （Cd） is one of the main pollution elements in China＇ s heavy metal contam- inated soil. As a research focus and frontier field in remediation of environmental contamination, phytoremediation is a green technology which has various advantages and is incomparable to other traditional soil contamination remediation methods. In this study, taking Solanum nigrum L. as the hyper-accumulator, pilot scale Cd phytoremediation was conducted in a Cd-contaminated crop field, Shenyang for two years. Analysis of Cd content in soil before and after phytoremediation showed that Cd removal was obvious. The average reductions in Cd level in the surface soil were 6.3% in the preliminary trial （PT） in the first year and 16.8% in the repeated trial （RT） in the second year, respectively. In PT and RT, the removal rates of Cd were 50.6% and 49.5% in the 20-40 cm layer, and 73.5% and 53.9% in the 40-60 cm layer, and 80.7% or not detected in the 60-80 cm layer, respectively. Data suggested that the biomass of the S. nigrum correlated significantly with the total Cd content accumulated in plants. The result from these tri- als showed that suitable soil condition in the field promoted the production of plant biomass to improve the ability of hyperaccumulator S. nigrum for Cd uptake and transporting trom soil. Uur study indicated that it is suitable to remediate the Cd contamination in Cd mildly-to-moderately polluted soil and realize the optimum cycle of agricultural production by phytoremediation technique.