粉煤灰污泥混料改良对重金属在植物体内的迁移及其生物有效性的影响研究

The Effects of Fly Aah and Sewage Sludge Ameliorants on the Transfer of Heavy Metals in Plants and Biological Effectiveness

本文通过盆栽试验研究以粉煤灰和污泥混合物为主要添加剂改良石灰岩质退化土壤后对玉米生长发育的影响,并根据重金属富集系数探讨重金属在玉米体内的迁移状况及其生物有效性。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,其养分具有缓慢释放的效果。重金属分析结果显示,不同配比条件下的生长介质中,重金属含量符合国家二级土壤质量标准,粉煤灰污泥混合物的加入未提高重金属从土壤中向植物迁移的能力和其生物有效性,重金属的富集系数大小均表现为:Cd>Hg>As,且S/R比值表明,重金属在玉米体内运输的能力较弱,主要累积在根系中。由此应注意选择非根果实植物种植,可大大降低食物链危害的风险。

Land disposal of fly ash（FA） and sewage sludge（SS） is a major problem due largely to their potentially harmful constituents.Previous studies,however,showed that the combined use of FA and SS might help reduce the associated pollution potential.In this paper,pot-planting experiments were performed to evaluate the effects on the plant growth and heavy metal accumulation characteristics in the plants when soils were amended with the mixture of FA and SS.The results showed that the application of FA and SS was significantly capable of accelerating the growth of plants,and the nutrients could be released slowly.Analysis of heavy metals indicated that the contents of Pb,Cr,Hg,Cd,As,Ni,Cu and Zn came up to the second-class environmental quality standards of soil,and the mixture of FA and SS didn＇t increase the capacity to transfer the heavy metals from soils to corns and the biological effectiveness.On the other hand,the contents of all the heavy metals in plant tissues were substantially lower than their toxicity limits,and the values of S/R showed that the transfer ability of heavy metals in the plants was weak and the metals were mainly accumulated in roots.Consequently,the land application of FA-SS mixture might result in the accumulation of some heavy metals in plant tissues,but the probability of affecting human health through the food chains would be reduced considerably by selecting the plant whose fruit is above its root.