The Research Of Groundwater Pollution Sources Strength Assessment Method Based On The Quantitative And Semi-quantitative

The evaluation of groundwater pollution sources intensity, which regards pollution sources as theresearch object provide theoretical basis for pollution prevention and it’s also the basic work ofgroundwater protection. According to “pollution sources and pathways”, the pollution sources and thefragility of the unsaturated zone are analyzed. Based on the groundwater pollution theoretical, the researchestablishes a quantitative and semiquantitative evaluation model of groundwater pollution sources intensityand then it is applied to the landfill site. The main research results and conclusions are as follows:(1)The evaluation index system of groundwater pollution sources intensity contains evaluationparameters of pollution sources and unsaturated zone. There are pollution factors comprehensive evaluation,emission load, the manner of sewage discharged, lifespan, and area ratio protection in the evaluation ofsources index. The groundwater vulnerability index includes groundwater depth, vadose medium, vadosemedium thickness and aquifer thickness, etc.(2)Compared with the existing evaluation methods, the study absorbs Correction-Nemerow index andsets up the evaluation model of groundwater pollution harm by Overlay and Index method. According tothe current situation of our country, the evaluation of groundwater vulnerability is carried out by themodified DRASTIC model. The semi-quantitative assessment model of the groundwater pollution sourcesintensity is founded by matrix method. The evaluation is applied to research zone by the semi-quantitativeassessment model. The result of the evaluation indicates that the informal landfill pollution sourcesintensity is higher than others.(3)According to Hydrus-1D and the literature review, the thesis founds the quantitative evaluationmodel of the groundwater pollution sources intensity which is based on process simulation. The model isused to evaluate the groundwater pollution sources intensity in the landfill. The result shows that thecadmium concentration is5.17×10-4mg/L is five times as high as the Groundwater Environment QualityStandard (GB/T14848-93). The cadmium contamination has large effect on the groundwater in landfillwhich matches with the result of the semi-quantitative assessment model. The information of groundwater water quality monitoring demonstrates that the concentration of cadmium is5.0×10-4mg/L. On the onehand, it turns out that the simulation matches with the reality. On the other hand, it indicatesthe reliability of the semi-quantitative and quantitative reliability evaluation.(4)It defines the concept of reduction function which means the ratio of the concentration thatpollutants enter into hallow groundwater and the emission concentration. Considering the situation ofgeology in the landfill, the research discusses and gets the influencing factors of reduction. The thesis getscadmium’s reduction function in the unsaturated zone by process simulation and then builds quantitativeevaluation model which is based on reduction function. At last, it is applied to the evaluation of quantitativein the landfill. The results are the followings: Firstly, the cadmium’s reduction is0.013in the vadosezone medium. Secondly, the cadmium concentration that enters into the aquifer is5.13×10-4mg/L andthe standard deviation is0.013‰. The result of estimation is similar. As the result, the reductionfunction quantitative evaluation model’s reliability is proved.The foundation of groundwater pollution sources intensity’s quantitative and semi-quantitativeevaluation model provides theory basis for development and utilization of groundwater resources andpollution control. The study enriches and develops groundwater and related subjects and providestheoretical basis for management, prevention and control of groundwater.