重庆某废铅冶炼厂重金属污染土壤微观结构特性研究

污染土壤微观结构研究中,室内试验制备的土样比较理想,而实际污染现场的土质极其复杂。为研究现场重金属污染土壤微观机理,开展了铅、砷、镉污染等重金属污染土基本物理性质指标试验和微观结构测试。首先,利用电感耦合等离子体发射光谱仪(ICP-MS)测定现场土样污染物类型及含量,建立现场土体重金属含量分布;然后,采用扫描电子显微镜(SEM)进行表面微观形貌试验,揭示污染土表面微观形貌,并通过颗粒(孔隙)及裂隙图像识别与分析系统(PCAS)定量分析土体试样的孔隙率,分析试样孔隙随重金属污染含量的变化规律;最后,从土壤环境的物质组成与结构及土壤性质方面分析土体微观形貌的变化机理。

Study on Microstructure of the Heavy Metal Contaminated Soil under an Abandoned Lead Smelting Factory in Chongqing

Soil samples for laboratory tests can be manufactured ideally in the analysis of microstructure of contaminated soil. However, properties of the soil in contaminated sites are extremely complicated. In order to investigate microcosmic mechanism of the heavy metal contaminated soil in contaminated sites, tests for physical mechanics property indexes and microstructure of the lead, arsenic and cadmium contaminated soil are conducted. Types and contents of the contamination in the polluted soil are determined by the Inductively Coupled Plasma Mass Spectrometer (ICP-MS) to establish contamination distributions of the site soil. Surface micro-topography tests are carried out by Scanning Electron Microscope (SEM) to reveal characteristics of the surface morphology of contaminated soil. Quantitative analysis in porosity of the contaminated soil is conducted by the Particles (Pores) and Cracks Analysis System (PCAS) to determine the variation law of the soil porosity with contents of heavy metals. Moreover, mechanisms of the micro-morphology of contaminated soil are analyzed from perspectives of soil components, soil structures and soil properties.