利用粉煤灰污泥混料改良石灰岩质土壤后的重金属累积状况

通过盆栽试验研究以粉煤灰和污泥混合物为主料,改良石灰岩质土壤后对玉米生长发育的影响,根据重金属富集系数,探讨重金属在土壤和玉米中的累积状况。试验结果表明:石灰岩质土壤中添加粉煤灰污泥混合物后能显著促进玉米的生长和提高玉米的干物重,其中以1:1重量比处理玉米的平均株高、株径及根部、地上部、总干物重分别是对照样的1.56、1.71、1.36、3.81和2.37倍。以不同配比添加混合物后的土壤相对于国家土壤背景值和国家土壤环境质量标准,Hg和Cd表现强烈富集,整体符合国家二级土壤质量标准,且玉米根部几乎所有有害元素的含量均高于对照组,而地上部分除Cu、Zn外均显著低于对照组,但均未达到玉米毒害浓度。另外,在土壤中添加混合物后玉米中几乎所有的有害元素主要累积在根部,有利于其地上部分的生长,减少了通过食物链危害人类的机率。

Heavy Metal Accumulation in Fly Ash-and Sewage Sludge- Amended Calcific Soil

The research on the amendment or reconstruction of calcific soil by the utilization of fly ash and sewage sludge mixture has been seldom reported,so a pot experiment was performed to evaluate the feasibility of using the mixture as calcific soil additive and the effects of the mixture on the growth of corn.Characteristics of the heavy metal accumulation in the amended soils and in corn tissues were discussed in particular according to the accumulation coefficient.The results showed that the application of fly ash and sewage sludge was significantly capable of accelerating the growth of corn and improving the dry weight yields.The height,diameter,as well as the root,shoot,and total dry weight yields of the corn at 1∶1(w/w) soil mixing ratio were 1.56,1.71,1.36,3.81,and 2.37 times,respectively,than those of the control.Compared with the Element Background Values of Soils in China and Soil Environmental Quality Standards,Hg and Cd in both the amended soils presented significant accumulation,and generally the soils met the second class standard.Nearly all the heavy metals content in root tissue were higher than that of the control,while in shoot,all the contents except Cu and Zn were lower.Moreover,no excessive accumulation of heavy metals was observed from the corn tissues,and the heavy metals mainly accumulated in root tissue,which benefits the growth of shoot and reduced the probability of affecting human health through food chains.