基于评分指数法的地下水污染风险评价——以甘肃省嘉峪关市的平原区为例

Groundwater pollution risk assessment based on grading index method:a case study in plain area of Jiayuguan City,Gansu Province

地下水污染风险评价是地下水基础环境状况调查研究的关键工作,也是开展地下水污染防治的重要技术依据。目前,地下水污染风险评价方法仍然以定性为主,因此基于评分指数法提出了定量化方法,对甘肃省嘉峪关市的平原区进行评价,并采用地下水硝酸盐数据对评价结果进行验证。结果表明:甘肃省嘉峪关市的平原区地下水脆弱性有较低、中等、较高3级,其中较高区主要分布在嘉峪关断裂附近和北大河沿岸地段;地下水污染源荷载等级高、较高、中等、较低和低都有分布,等级中等至高的区域主要分布在主城区北部的工业园区;地下水利用价值总体为中。综合地下水脆弱性、地下水污染源荷载和地下水利用价值进行地下水污染风险评价,低、中、高风险区分布面积分别为325、393、212 km^(2),高风险区主要分布在东北部新城镇横沟村至泥沟村一带的地下水溢出带和北大河沿岸地段。用地下水硝酸盐数据验证基本吻合。

Groundwater pollution risk assessment is a key work for the investigation and research of groundwater basic conditions and an important technical support for groundwater pollution prevention and control.The groundwater pollution risk assessment has not been quantified,so the quantitative method based on grading index method was proposed,and it was used to evaluate the plain area of Jiayuguan City,Gansu Province.The results were verified by groundwater nitrate data.Results showed that relative low,medium and relative high groundwater vulnerability were distributed in the studied area,and the relative high areas were mainly distributed near the Jiayuguan fracture and riverside of Beidahe River.Low,relative low,medium,relative high and high groundwater pollution sources’load all existed,and the medium to high areas were mainly distributed in industrial parks in the north of urban areas.The groundwater utilization value was medium in general.Groundwater vulnerability,groundwater pollution sources’load and groundwater utilization value were combined to evaluated the groundwater pollution risk.It was divided into 3 areas with low,medium and high groundwater pollution risks,the distribution areas of which were 325,393 and 212 km^(2),respectively.The high risk area were mainly distributed in groundwater overflow zone from Henggou Village to Nigou Village of Xincheng Town,and riverside of Beidahe River.Groundwater nitrate data turned to be verified.