Department of Environmental Science and Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu, 610065, China.
College of Resources and Environmental Sciences, Northwest Agricultural and Forestry University, Xianyang, 712100, Shanxi, China.
Environ Monit Assess. 2021 Jan 11;193(2):54. doi: 10.1007/s10661-020-08836-8.
The heavy metal pollution level in soils is heavily affected by the soil particle size distribution. However, the heavy metal loss during particle size extraction and the effect of calcite on the heavy metals removal in terms of the particle size are unclear. In this study, the distribution of heavy metals (Cu, Cd, Cr, Co, Ni, Zn, Pb, U, and V) was determined in five particle fractions (> 2, 2-0.25, 0.25-0.02, 0.02-0.002, and < 0.002 mm) of two soil and one sediment samples collected from the floodplain of Dongchuan, Yunnan Province, Southwest China. The sampled floodplain soils were mainly composed of gravel and sand fractions (> 97%). The concentrations of all nine heavy metals in the sampled soils and sediment increase significantly with decreasing particle sizes. The maximal loss rate of Cd and Cu reaches 54% and 8.6%, respectively, which should be considered in the process of particle size fraction extraction in soils. The removal amount and removal rate of heavy metals in solution by pure calcite ranks in the order of Pb > Cu > Cr, while the removal rate of Pb (93.13%) is much higher than that of Cu (24.56%) and Cr (10.71%), which increase with the calcite particle size decreasing. The stabilization of carbonate minerals in soils is crucial for heavy metal pollution control in floodplain soils with high carbonate concentrations in Dongchuan, China.
土壤中重金属污染水平受土壤颗粒大小分布的影响很大。然而，颗粒大小提取过程中重金属的损失以及方解石对重金属去除的影响尚不清楚。本研究测定了来自中国西南云南省东川洪泛区的两个土壤和一个沉积物样本中五种颗粒大小（>2、2-0.25、0.25-0.02、0.02-0.002 和<0.002 mm）中重金属（Cu、Cd、Cr、Co、Ni、Zn、Pb、U 和 V）的分布。采样的洪泛区土壤主要由砾石和砂粒组成（>97%）。在所采样的土壤和沉积物中，所有九种重金属的浓度随颗粒大小的减小而显著增加。Cd 和 Cu 的最大损失率分别达到 54%和 8.6%，这在土壤颗粒大小提取过程中应予以考虑。纯方解石对溶液中重金属的去除量和去除率的顺序为 Pb>Cu>Cr，而 Pb（93.13%）的去除率明显高于 Cu（24.56%）和 Cr（10.71%），且随着方解石粒径的减小而增加。在中国东川碳酸盐浓度较高的洪泛区土壤中，控制重金属污染的关键是稳定土壤中的碳酸盐矿物。
