四川盆西平原区裸土扬尘中Pb、Cd化学形态的尺度效应

为了探究四川盆西平原区裸土扬尘中Pb、Cd总量与其尺度效应的关系,模拟土壤样品的Pb、Cd污染,通过实验室内的模拟起尘研究系统对土壤样品开展试验,对各粒级悬浮颗粒物中Pb、Cd的赋存状态及其尺度效应进行分析,并进一步对土壤中的黏土颗粒进行提取分析,结果表明:试验条件下,随着粒径的减小,Pb、Cd在四川盆西平原区裸土扬尘颗粒物中的总质量分数却增加,呈现出负相关;Pb的碳酸盐结合态、铁锰水合氧化物结合态主导着其全量的尺度效应,Cd的交换态、碳酸盐结合态、铁锰水合氧化物结合态主导着其全量的尺度效应;裸土扬尘中黏土矿物(伊利石+绿泥石)的尺度效应是影响其Pb、Cd化学形态尺度效应的重要因素。

The scale effects of the chemical forms of Pb,Cd contained in dust flying from bare soil in west plain,Sichuan

In order to understand the relationship between the total content of Pb and Cd contained in dust flying from bare soil in west Sichuan Plain and the scale effect,the contamination of Pb and Cd in soil samples was simulated and experiments were carried out on the soil samples based on the indoor dust generation simulation system in the laboratory.The occurrence of Pb,Cd in suspended size fractions and the scale effect were studied together with further analysis of the clay particles extracted from the soil.The results show that under the experimental conditions,as the particle size of the fraction decreases,the total content of Pb and Cd contained in dust flying from bare soil will increase,representing a negative correlation.The Carb-Pb(bound to carbonates)and FMO-Pb(bound to hydrated iron and manganese oxide)dominate the scale effect of the total,while the EXC-Cd(cadmium exchangeable)and Carb-Cd(bound to carbonates),FMO-Cd(bound to hydrated iron and manganese oxide)dominate the total scale effect of the total.The scale effect of clay minerals(illite and chlorite)contained in dust flying from bare soil is the critical factor influencing the effect of chemical forms of Pb and Cd.