Risk Assessment Of Groundwater Pollution In Liaoning Province

At present,the water quality of groundwater supply sources in many large and medium-sized cities have deteriorated,and gradually developed into deep water.At the same time,groundwater pollutants have changed from single to complex,and the pollution range has also changed to surface and large-area pollution.As one of the water-deficient areas in northern China,Liaoning Province had some problems such as deterioration of groundwater quality and seawater intrusion.In this paper,Liaoning Province was used as the research area,and the groundwater pollution risk model was adopted.The groundwater pollution risk assessment was based on the inherent vulnerability of groundwater,external stress,and groundwater functional value,combined with DRASTIC model and GIS platform.The evaluation results were further divided into five levels.Then an industrial site in the Liaoning Coastal Economic Development Zone of Panjin city in the area of highest pollution risk level was selected as the next study area.Based on hydrogeological survey data,established a groundwater flow model in the study area,solved with the MODFLOW module in GMS based on finite difference method.The solute transport model was established,and three pollutants of phenol,ammonia nitrogen and petroleum were selected.The solute transport of pollutants was simulated by Hydrus-1D and GMS in a scenario simulation mode.The risk assessment model was used to evaluate the site.The main conclusions are as follows:1.The inherent vulnerability of groundwater in Liaoning Province was at a lower to higher level,and the inherent vulnerability index was between 0.30 and 0.64.The external stress index was between 0.06 and 0.72,and the stress in the western and eastern regions was low.The Liaohe Plain and the southern Dalian had a large external stress index.Two-thirds of the regions in Liaoning Province were below the medium-function value,and the overall functional value was low.The functional value index was between 0.06 and 0.64.The functional value of the Liaohe Plain is higher,and the western and eastern regions were lower.The groundwater pollution risk index of Liaoning Province is between 0.04 and 0.75.The western and eastern regions are less risky and the central region is more risky.2.Under the scenario 1,the risk level of ammonia nitrogen in the simulation time of 700 days to 4900 days was grade I,the risk level was grade II to 7300 days.The risk levels of phenol in the simulation time of 700 days,1400 days,and 2100 days were Grade I,III,and IV,respectively,and were all VI-level high-risk states during the 7300 days;under the scenario 2,the pollution concentration of phenol,ammonia nitrogen and petroleum pollutants gradually decreased,and the decay rate also gradually decreased.The ammonia nitrogen and petroleum were reduced from grade IV and grade VI to the grade I respectively.Phenol has been in a high-risk state at the VI level during the simulation.