Analysis And Prediction Of Environmental Quality Differences Of Urban Groundwater Quality

Groundwater flow is very slow due to the complexity of the geology below the surface.Once groundwater is contaminated,it will take more than a decade or even decades to restore water quality even if it is completely eliminated.Therefore,this paper takes the first water source in Suihua City as the research object,and evaluates the groundwater quality of 13 monitoring wells by single component evaluation method and comprehensive evaluation method.Taking Suihua Zhongmeng Thermal Power Co.,Ltd.and Suihua Jinlong Grease Co.,Ltd.as typical contaminated sites,Visual MODFLOW software was used to analyze the mechanism of pollutant migration and transformation and pollution receptors,and predict the time when downstream residents threatened groundwater.This paper collected groundwater samples from the recharge area of the first water source in Suihua City.Within the scope of the recharge area,10 wells can be used for the wells and enterprises,and 1 well for the first water source.The groundwater sampling analysis is carried out,and the sampling results are evaluated and analyzed.The groundwater quality of 13 monitoring wells was evaluated using the one-component evaluation method and comprehensive evaluation method in “Groundwater Quality Standards”(GB/T 14848).The water quality of the first water source in Suihua City and the comprehensive evaluation results of the remaining monitoring wells were poor.The main over-standard factors in the first water source area are iron,manganese,ammonia nitrogen and total alpha radioactivity;the over-standard indicators in other water well monitoring indicators in the first water source recharge area are iron,manganese,ammonia nitrogen,total dissolved solids and total hardness.The pollution status was evaluated by the pollution index Pki method.The spatial distribution of dissolved total solids,sulfate,chloride and total hardness showed a similar trend,and the high value areas appeared in E,X1,B7,B8 and B9 wells.The high ammonia nitrogen zone appears at X1,which may be related to the landfill.The high permanganate index area appeared in E,and the nitrate nitrogen high value area appeared in B8,and the spatial distribution of arsenic concentration did not change.Groundwater pollution is mainly related to two factors: first,the natural poor water quality caused by the geological environment;second,various types of pollution sources.In the simulation prediction and evaluation,the groundwater flow model was established by Visual MODFLOW software to simulate the migration and transformation process of ammonia nitrogen in groundwater.It is expected that groundwater in downstream residential areas will be threatened after 10 years,that is,it exceeds groundwater quality class III.