不同土壤处理对东南景天吸取土壤中锌和镉效率的影响

Effects of soil treatments on the extraction of Zinc and Cadmium from contaminated soil by Sedum alfredii Hance

通过盆栽试验,观察分析东南景天植物在未处理及若干用土壤添加剂处理的土壤介质上生长和累积锌、镉的状况。结果显示:除单独使用沸石粉外,所有土壤处理均有利于土壤改良和东南景天的生长。与对照处理相比,赤泥和城市污泥对东南景天累积锌起促进作用,而施用熟石灰却无助或甚至不利于东南景天累积锌。不过,尽管赤泥和城市污泥对东南景天累积镉的效果比熟石灰好,无论施用赤泥、城市污泥或熟石灰,东南景天植物干物质所含的镉均比对照处理高得多。总的来说,赤泥和城市污泥均为改良土壤、促使东南景天生长和超累积锌、镉的良好添加剂;而熟石灰或沸石粉单独使用则对东南景天超累积锌、镉的作用较小。在试验中,将15g污泥、15g沸石和6g赤泥与1000g土壤混和的T7处理对促使东南景天生长和超累积锌、镉最为有效。研究结果表明,在利用东南景天修复酸性锌、镉污染土壤时,通过加入合适的改良剂,调控土壤pH值和营养供给,可大大提高植物修复重金属污染的效果。

A pot experiment was conducted to compare the effects between the untreated contaminated soil and the amended contaminated soils on the growth ofSedum alfredii Hance and the extraction of Zn and Cd by this plant. The results show that all soil treatments except for sole use of zeolite have improved soil conditions for the growth of Sedum alfredii Hance. In comparison with the control,treatments of the soil with red mud or/and biosolids enhanced the accumulation of Zn in the plant tissues while treatments of soil with hydrated lime had adverse effects on the extraction of Zn by Sedum alfredii Hance. However, all treatments enhanced the extraction of Cd by Sedum alfredii Hance although the red mud and biosolids had better effects than hydrated lime on the accumulation of Cd in the plant tissues. Overall, red mud and biosolids appear to be good soil conditioners for Sedum alfredii Hance in terms of phytoextraction of Zn and Cd from the contaminated soil. The effects of hydrated lime or sole use of zeolitic rock powder on the phytoextraction of Zn and Cd by Sedum alfredii Hance were limited or minor. In this experiment, Treatment 7 (mixing 1000 g of the contaminated soil with 6 g of red mud, 15 g of zeolitic rock powder and 15 g of biosolids) formed a best soil medium for the growth of Sedum alfredii Hance that achieved the greatest removal rate of Zn and Cd from the contaminated soil. The results indicate that phytoextraction of Zn and Cd from the contaminated soils by Sedum alfredii Hance can be enhanced by soil amendments to reduce soil acidity and improve nutrient supplies.