不同工业废弃物对稻田土壤中镉 铅生物有效性及其形态的影响

应用盆栽试验研究了几种工业废弃物对水稻土壤中Cd、Pb的生物有效性及其形态的影响,以寻找有效的土壤重金属化学修复技术应用于当前轻度污染土壤.结果表明,施用纸厂滤泥、石灰使土壤交换态Cd比对照分别降低了47.6%、47.1%,糙米中的Cd含量分别比对照下降了61.3%、51.9%;使土壤交换态Pb比对照降低了93.8%、91.1%,糙米Pb含量下降了57.6%、61.8%.铁尾渣、粉煤灰对降低土壤Cd、Pb生物有效性也表现了不同程度的效果.偏硅酸钠对降低污染土壤中糙米Cd的效果不明显,但降低糙米Pb效果显著,为53.3%,接近石灰和纸厂滤泥.纸厂滤泥为造纸厂废弃物,含高碱度和有效硅、磷酸盐,添加后不造成作物减产,且对降低稻田土壤Cd、Pb生物有效性具有显著的效果,因而是一种有效的、低成本化学修复技术.

Effects of Different Industrial Wastes on Bio-availability of Cadmium, Lead and their Formation in Paddy Soils

The effects of different industrial wastes on bio-availability of cadmium and lead and their formations in paddy soils were studied using pot experiment, in order to search available chemical remediation technique for current light-contaminated soil. The result showed that compared with the control, the soil exchangeable Cd decreased 47.6% and 47.1%, which resulted in the decline of Cd content in brown rice by 61.3% and 51.9%, respectively, by adding paper mill sludge and lime, and the soil exchangeable Pb decreased 93.8% and 91.1%, with Pb contents in brown rice declining 57.6% and 61.8%, respectively. Puddling dregs and fly sludge also showed certain effects on decreasing bio-availability of soil Cd and Pb. The addition of sodium meta-silicate had no obvious effect on decreasing Cd contents in brown rice of contaminated soil, but had significant effect on Pb contents in brown rice (being 53.3%, near to that of lime and paper mill sludge). Paper mill sludge, as a waste of paper factories, contained high alkalinity, available silicate and phosphate, did not reduce the rice yield, but had significant effect on decreasing bio-availability of soil Cd and Pb, so the application of paper mill sludge would be an available and least-cost chemical remediation technique.