Research On Assessment Method Of Groundwater Pollution Health Risk For Landfill Site

Groundwater pollution has been paid more attention gradually, so its health risk assessment has been very necessary. The risk level is selected as the evaluation benchmark in the health risk assessment of groundwater pollution; the groundwater pollution and human health is linked up, and the harm of groundwater contamination that human body suffering is quantitatively described. It can not only measure scientifically the degree of damage on the human body caused by groundwater pollution, but also provide reliable basis for groundwater pollution control and repair.With the health risk assessment of groundwater pollution being valued gradually, the appraisal method and contrast has important significance. The paper combines "Handbook of groundwater pollution health risk assessment technology ", and based on the United States NAS four footwork, two methods are presented:the monitoring evaluation and simulation prediction assessment using analytic solution, the index system about health risk assessment of groundwater pollution in landfill site is established; and through the combination with a northern landfill site, the health risk assessment is carried out; the two methods are compared, including the advantages, limitations and applicable condition. Through the research, the main achievements following:(1) The two methods of health risk assessment, monitoring analysis evaluation and simulation prediction assessment using analytic solution, are put forward; and their theoretical foundation is probed;(2) The index system about health risk assessment of groundwater pollution in landfill site is established conforming to our country national condition, including the index related to risk calculation, the index related to evaluation receptor, the index related to chemical substances and the index related to geological parameters;(3) After the investigation of a northern landfill site, the health risk assessment of groundwater pollution is carried out using the two methods and the proposed index system, separately considered the ways of drinking water (DW) and skin absorption, and the results show that DW way is the main exposure way in research area, benzene and nitrates are the main carcinogenic and non carcinogenic contributions of pollutants respectively. Through the evaluation, the management standard of landfill site is given, namely, in20years benzene and nitrate concentration will drop to0.34and30.(4) The main controlling factor of the simulation and forecast evaluation using analytical solution is analyzed. The results show that the permeability coefflcient(K)and half-life (t1/2) have the largest response degree to simulated result, and show higher sensitivity for the model, organic carbon distribution coefficient Koc) takes the second place, degree of longitudinal dispersion (ax)has minimum response to analytical solution model(5)The comparative analysis is about the advantages, limitations and the applicable conditions of the monitoring analysis evaluation and simulation prediction assessment using analytic solution; and the later has a larger scale and more extensively applicable scope,and applicable to simple geological conditions; the evaluation process of monitoring analysis is applicable to assessment for single geological structure and the pollutants having good chemical stability.