Study On Risk Assessment Of U(VI) Pollution To Groundwater Based On A Modified DRASTIC Model, GIS And An Analytic Hierarchy Process Method

With the development of the nuclear industry,the problem of the radionuclide contamination is becoming increasingly conspicuous. Especially, the radionuclides in the tailing stored and transfered into the soil over time, entered in groundwater and polluted groundwater, brought to the groundwater resource potential risks. however, Groundwater pollution risk evaluation can reflect the likelihood of the groundwater contamination under a certain contaminants or kinds of contaminants and potential harmfulness. For now, it mainly adopts DRASTIC model to evaluate groundwater inherent vulnerability, and it can only reflect itself ability against outside pollution, without consideration of factors such as external pollution sources. In this paper, the shortcomings of conventional model was improved, and built a new evaluation model.Regarding a uranium tailings as the study case,a DRASTIC model method was used to study groundwater vulnerability. Landuse and distance were added to the DRASTIC parameters to modify the model and establish a new model(DRASTICLL). To use analytic hierarchy process(AHP) to determine the weight of each parameter in the model and establish a comprehensive index system(AHP-DRASTICLL). Based on the geographic information system(MAPGIS)and draw up the groundwater intrinsic vulnerability mapping. Considering the existence of special pollution source U(VI) and coupling groundwater intrinsic vulnerability with contaminant sources,the risk mapping of groundwater contaminated with U(VI) was formed.The evaluation results showed that the new model wasmore scientific,reasonable and consistent with the facts. It can forecast the future risks, dynamic prediction and put forward preventivemeasures.The research results will provide technical support for our country in controlling non-point pollution of radionuclidein service or decommissioned uranium tailings.And it will be of great reference value in tailings of similar heavy metal pollution. Sothis study has very importat social and economic value.