Nai Changxin, Sun Xiaochen, Wang Zeya, Xu Ya, Liu Yuqiang, Liu Jingcai, Dong Lu, Huang Qifei, Wang Yuling
School of Information and Electronic Engineering, Shandong Technology and Business University, Yantai, 264005, China.
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
Sci Rep. 2019 Jul 29;9(1):10944. doi: 10.1038/s41598-019-47167-8.
Different pollutants affect electrical characteristics of soil, e.g., electric resistivity and capacity. The most extensively used non-intrusive methods in mapping these physical characteristics are electrical method. To better understand the effect of different hydrogeological and environmental process on resistivity and phase of complex resistivity under water-saturated soil, we carried out a controlled laboratory experiment where the host material was simulated by sand soil and the hydrogeological and environmental processes by groundwater table rise, seawater intrusion and heavy metal contamination. The experiment measured the resistivity and phase of soil saturated and unsaturated, with different pollutants added, together with their time-lapse change in a well-controlled column. With the involvement of more measurement parameters, complex resistivity method can provide more information than resistivity method, thereby having better performance in the detection and monitoring of changes in electrical properties of complex contaminated sites. For example, it is capable of discriminating the different contamination process, in this case, e.g., seawater intrusion and heavy metal contamination. In addition, it is still sensitive to the change of pollutant concentration even in site with high added concentration. Furthermore, simulating the saltwater-intruded site contaminated by manganese, it was found that the change of resistivity (ρ) can hardly be observed, while the responses of phase (φ) are so obvious that can be clearly observed.
不同的污染物会影响土壤的电学特性，例如电阻率和电容。在测绘这些物理特性时，应用最广泛的非侵入式方法是电学方法。为了更好地理解不同水文地质和环境过程对饱水土壤下电阻率和复电阻率相位的影响，我们开展了一项对照实验室实验，其中用砂土模拟主体材料，用地下水位上升、海水入侵和重金属污染模拟水文地质和环境过程。该实验测量了添加不同污染物时饱和及非饱和土壤的电阻率和相位，以及它们在一个控制良好的柱体中的随时间变化情况。由于涉及更多测量参数，复电阻率法比电阻率法能提供更多信息，从而在复杂污染场地电特性变化的检测和监测方面具有更好的性能。例如，它能够区分不同的污染过程，在此情况下，比如海水入侵和重金属污染。此外，即使在添加浓度较高的场地，它对污染物浓度的变化仍很敏感。再者，通过模拟受锰污染的海水入侵场地发现，电阻率（ρ）的变化很难被观测到，而相位（φ）的响应却很明显，能够清晰地被观测到。
