城市污泥人工土壤中重金属生物有效性及综合毒性研究

以城市污泥为主要成分,添加不同比例的单一辅料(草炭、磷矿粉、粉煤灰)配成不同的城市污泥人工土壤,研究各配比人工土壤中重金属生物有效性和综合毒性,并揭示人工土壤中重金属向黑麦草的动态迁移.结果表明:各配比人工土壤中重金属生物有效性和综合毒性均较污泥明显下降;当粉煤灰添加比例为20%时,人工土壤中Cu、Zn、Pb、Ni生物有效态含量下降最多,分别为28.75%、36.09%、34.85%和36.52%,此时,重金属综合毒性指数降幅最大,为2.7×10-3;与污泥相比,各配比人工土壤中重金属向黑麦草的迁移能力显著降低,非线性回归分析显示黑麦草中重金属富集浓度与人工土壤中重金属的生物有效态含量间存在正幂函数关系.

Bioavailability and comprehensive toxicity of heavy metals in artificial soil composed of sewage sludge

In order to evaluate the suitability of reclamation for mining wasteland by artificial soil composed of sewage sludge and varied constituents（peat,phosphate rock and fly ash）,the bioavailability and comprehensive toxicity of heavy metals in artificial soil were investigated.Furthermore,the pot experiments were conducted to determine the translocation of heavy metals in the artificial soil-plant（ryegrass） system.The results indicated that the bioavailability and comprehensive toxicity of heavy metals in artificial soil decreased significantly.When the ratio of fly ash to sewage sludge（on a mass basis） was 20%,the contents of bioavailable Cu,Zn,Pb and Ni in artificial soil were reduced by 28.75%,36.09%,34.85% and 36.52%,respectively,and hence,the index of comprehensive toxicity of heavy metals was decreased by 2.7×10-3.The amount of heavy metals accumulated by ryegrass grown in artificial soil was reduced significantly.Furthermore,there were power functions with positive coefficients relationships between the concentrations of heavy metal in ryegrass and those of bioavailable heavy metals in artificial soil.