基于“ERT”的土壤污染原位修复监测技术试验研究

ERT-based experimental study on monitoring technology for in situ remediation of soil contamination

为及时发现土壤污染变化情况、制定修复方案,在高密度电阻率法(ERT)的基础上进行了污染土壤原位修复动态监测技术试验。试验选取自来水、Na Cl溶液、硝酸铜溶液和磷酸二氢钠溶液、硝酸铜溶液和柠檬酸溶液四组试剂在土壤中渗透扩散,监测扩散过程中的视电阻率变化情况,绘制视电阻率等值线图和视电阻率变化量等值线图,并反演得到电阻率等值线图和电阻率变化量等值线图,分析数值变化的内在联系,验证土壤中离子变化情况引起电阻率变化的结论。结果表明:引起电阻率变化的原因在于土壤离子的活性和电离程度;土壤中离子浓度降低,电阻率增大;离子浓度增大,电阻率降低;电阻率变化量的幅值变化速率反映出土壤修复的快慢,幅值变化速率越快,反映出修复进程越快。研究成果为土壤污染动态监测提供了监测指标,有利于监测装置的改进,为精确修复土壤奠定基础。

In order to timely find out the variation of soil contamination and work out the relevant remediation scheme,the experiment on the dynamic monitoring technology for the in situ remediation of the contaminated soil is carried out based on electrical resistivity tomography（ERT）. For the experiment,four sets of testing agents,i. e. tap water,Na Cl solution,copper nitrate solution and sodium dihydrogen phosphate solution,copper nitrate solution and citric acid solution,are selected to infiltrate and diffuse into soil; from which the variation of the apparent resistivity during the diffusion is monitored and both the contour diagram of the apparent resistivity and the contour diagram of the variation of the apparent resistivity are drawn,while the resistivity contour diagram and the contour diagram of the variation of the resistivity are obtained from the relevant inversion,thus the internal relation of the numerical variation is analyzed and the conclusion of that the variation of the resistivity is caused by the variation of the ion in soil is verified. The result shows that the causation of the variation of the resistivity depends on the activity and the ionizationdegree of soil ion,i. e. the resistivity is to be increased,if the ion concentration in soil is decreased,while if the ion concentration is increased,the resistivity is to be decreased. The changing rate of the amplitude of the variation of the resistivity reflects the speed of the soil remediation; i. e. the faster the changing rate of the amplitude is,the faster the response progress is to be. The study result not only provides the monitoring indexes for the dynamic monitoring of soil contamination,but also is favorable for the improvement of the relevant monitoring devices,thus lays a basis for accurate remediation of the soil.