太原地区公路旁土壤中重金属形态分布和生物有效性研究

采用盆栽试验结合形态分析技术研究了太原地区公路旁污染土壤中Pb,Cd,Cu和Zn的形态分布及其生物有效性。研究结果显示:除Cd外,残渣态是主要形态,可交换态的含量很少;土壤中Cd的碳酸盐结合态、可交换态含量较高,残渣态的含量很少;菜园土重金属的生物可利用性和迁移能力的顺序均是Cd>Cu>Zn>Pb,而高粱土的顺序是Cd>Zn>Cu>Pb,菜园土重金属的生物活性和迁移性较高粱土的大。农作物对Cd,Cu和Zn的累积能力远远大于对Pb的累积能力,且Cd,Cu和Zn向地上部转移的速度也明显比Pb快。研究成果将为评估污染土壤中重金属的危害提供科学依据。

The Fraction Distribution and Bioavailability of Heavy Metals Pollutants in Soil along Highway in Taiyuan Area

The fraction distribution and bioavailability of Pb,Cd,Cu and Zn in soil along highway in Taiyuan were studied by pot experiment and a sequential extraction. The results indicated that the residual fraction was the predominant fraction except Cd in four contaminated soils. However,the proportions of exchangeable fractions were the lowest among all fractions. On the other hand,the proportions of carbonate compounds and exchangeable fractions for Cd were relatively high,but the proportions of residual fractions were the lowest among all fractions. In addition,both the availabilities and mobilities of heavy metals in vegetable soil followed Cd > Cu > Zn > Pb,respectively,and in broomcorn soil were Cd > Pb > Zn > Cu. The availabilities and mobilities of heavy metals in vegetable soil were higher than those in broomcorn soil. The plant accumulations of Cd,Cu and Zn in soils were higher than those of Pb. Also,the plant transformations of Cd,Cu and Zn from soil to the upper part of shoot were faster than those of Pb. The results will provide scientific bases for assessing the harm of heavy metals in contaminated soils.