基于保护地下水的土壤修复目标层次化制定方法分析

Analysis on Hierarchical Formulation Method of Soil Remediation Objectives Based on Groundwater Protection

根据土壤对地下水污染程度复杂性,按照污染物由土壤到地下水再到下游水井的过程,将其划分为三个层次。在选定的污染场地上,与规定的标准最低限定值接近的是第一层和第二层的土壤修复目标值。而污染物迁移更完整、更能反映实际情况的是第三层次的修复。通过对目标参数敏感性分析,土壤中含有的有机质质量分数、有机碳水分配系数和渗入速度对土壤修复目标值影响最大。根据实验或调查制定土壤修复方案,从而确定修复目标值的稳定性。研究表明,污染场地的修复目标可以依据第三层次土壤修复评估结果,即可以解决下游饮水井的水质质量,也可以控制土壤修复的平衡性。

According to the complexity of soil pollution to groundwater and the process of pollutants from soil to groundwater and then to downstream wells,it is divided into three levels.The layered assessment framework method is used to formulate the method of soil remediation target based on groundwater protection,and determine the soil remediation target value of the selected contaminated site.The measurement results show that if the water quality in the drinking well is not reduced,the pollutant components that need to be repaired will gradually decrease with the gradual improvement of the assessment level,and the amount of earthwork to be repaired will also change from more to less,so as to minimize the repair cost.On the selected contaminated site,the target values of soil remediation for the first and second layers are close to the specified standard minimum limit values.The third level of remediation is more complete and reflects the actual situation.Through the sensitivity analysis of target parameters,the mass fraction of organic matter,organic carbon water partition coefficient and infiltration rate in soil have the greatest impact on the target value of soil remediation.The soil remediation scheme should be formulated according to the method of experiment or investigation,so as to determine the stability of the remediation target value.The research shows that the remediation target of the contaminated site can be based on the results of the third level soil remediation assessment,which can not only solve the water quality of the downstream drinking water wells,but also control the balance of soil remediation.