The Study On Water Environmental Risk Assessment And Control Measures Of The Surface Dringking Water Source In Hohhot

In recent years,frequent pollution incidents in water supply sites have affected safety of drinking water,but the research and application of risk assessment in drinking water sources can effectively prevent such incidents.This study takes the Hohhot centralized surface drinking water source as the research object.First,the primarystudy is to analysis pollution characteristics and evaluate environmental quality of the research area through 7 monitoring sections with 30 monitoring indicators.Further screening key indicators and ranking the section score by principal component analysis are in order to construct risk evaluation model of water environmental risk assessment in the study area,as well as the evaluation results are characterizedbyArcGIS.Finally,it puts forward reasonable risk prevention measures according to the evaluation results.The main research conclusions are as follows:(1)Based on the analysis of characteristics of water pollution in the study area from 2011 to 2015,the research area shows the trunk stream is clean but the tributary is polluted by CODCr,BOD5,ammonia nitrogen,total phosphorus,fecal coliform,petroleum et al;(2)Water environmental quality assessment of three water stage form 2011 to 2015 in study area,determined ammonia nitrogen and total phosphorus are main pollutants and dry season is the most serious when the biggest exceeding section is Hunjinqiao with7.0 and 7.2,respectively.The comprehensive-risk evaluation results show that in Hohhot,the Yellow River water quality is in class ?,the water quality of tributary,Daheihe and Xiaoheihe for is worse classified in class ?.Hohhot surface drinking water source meet the standard of the class ?;(3)Three principal component index was filtered out by principal component analysis:F1(ammonia nitrogen and total phosphorus),F2 and F3(CODCr and BOD5)(fecal coliform group),then ranking monitoring section score,Hunjinqiaoranked first that means it was seriously polluted,but three section in the Yellow River mainstream are ranking for the last three.(4)Three phases of water were assessed and grade judged by the risk evaluation model respectively.Three principal components are at a higher level of risk in the section of Hunjinqiao,especially the risk of F1.Three main components of the Yellow River main stream and the surface water source of Hohhotin three water periods belong to the low risk level.The risk of Hunjinqiao water environment in the three years from 2013 to 2015 was evaluated,and the risk of the F1 and F2 tributaries was borth reduced by one level,indicating the improvement of environmental quality,but the F3 did not improve significantly.(5)According to the results of risk assessment and the present situation of environmental quality evaluation,three major risk prevention measures are put forward:?Control the illegal phenomenon of protected areas,and monitor potential risk source ? Manage and control the organization of rural non-point source pollution ?Strengthen the Hohhot city each big enterprise emission regulation and sudden accident emergency plan established.