Health Risk Assessment And Prediction Of Groundwater In Plain Area Of Baiyangdian Basin

Accurately quantifying groundwater environmental health risks,identifying priority risk sources,exposure pathways and risk receptors,and predicting risk development trends are the prerequisites for efficient management and control of risks and ensuring the safety of using water for people.In view of this,this paper takes the plain area of Baiyangdian Basin as the study area.Using data collection,field investigations,laboratory experiments,and numerical simulation methods,this article comprehensively assesses and predicts groundwater environmental health risks from"multiple pollution sources-multiple pollutants-multiple exposure pathways-multiple exposure receptors".Based on this,the groundwater environmental risk management and control measures are put forward.The main achievements of this paper are as follows:（1）The average concentration of pollutants in the groundwater from high to low is:NO₃^->F>Mn>NO₂^->Zn>Cr⁶⁺>As>Pb>Cu>Hg>Cd.Among them NO₃^-,F,Mn,As and Pb have exceeded the standard,and the over-standard rates are 34.62%,30.77%,28.85%,4.87%and 4.87%respectively.On the spatial scale,the concentrations of NO₃^-and Cr（VI）gradually decrease from the floodplain in the western piedmont zone to the eastern lacustrine plain.And the other 9 pollutants all show different degrees of enrichment in the lacustrine plain.（2）There are 5 potential sources of groundwater environmental health risks in the area.The combined source of human activities and hydro-geochemistry with Mn,F,As and Hg as characteristic elements is the main source of pollutants in groundwater in the study area,contributing 30.98%.The compound source of industrial and agricultural activities with high loads of Pb,Cu and Cd,contributing 22.73%.Agricultural pollution sources,with NO₃^-and NO₂^-as representative pollutants,contribute 21.26%.Natural sources represented by Cr（VI）accounted for 14.09%,and industrial sources represented by Zn accounted for 10.94%.（3）The groundwater environmental health risk in the study area is generally acceptable,but the maximum value exceeds the threshold,which should arouse the necessary attention.From the perspective of toxic effects,the carcinogenic risk is much higher than the non-carcinogenic risk.In particular,Cr（VI）is a priority carcinogen due to its obvious carcinogenic effect,while NO₃^-is a priority non-carcinogenic factor due to serious pollution.From the perspective of risk sources,the carcinogenic risk is mainly derived from natural sources,contributing 79.61%,while the non-carcinogenic risk is mainly caused by agricultural sources,contributing 44.38%.Comparing the exposure routes and risk receptors,drinking water is the main exposure route,and the risk of women is slightly higher than that of men.（4）Within 15 years of the construction of the Xiongan New Area,the carcinogenic pollutant Cr（VI）in the groundwater will not affect the groundwater quality of the Xiongan New Area and Baiyangdian under the condition of only natural Cr（VI）sources of replenishment.This is mainly because measures to reduce mining volume and ecological water replenishment have formed a watershed of groundwater and hindered the migration of pollutants in the upstream groundwater.In addition,the particles of the aquifer medium in the lacustrine plain are relatively fine,which is not conducive to the migration and diffusion of pollutants.For the next 15 years,the groundwater quality has improved in areas where NO₃^-of non-carcinogenic pollutants exceed the standard severely.However,due to agricultural fertilization and surface nitrogen supply from domestic sewage,groundwater quality in areas with low NO₃^-concentration is deteriorating,and attention must be paid.From 2020 to 2035,the carcinogenic risk of groundwater environment will slowly decrease.However,only the natural restoration of the aquifer system will not reduce the risk to an acceptable level in the higher-risk area 15 years later.Therefore,the area should be treated and repaired.As for the non-carcinogenic risk of groundwater environment,areas with relatively high non-carcinogenic risks in the alluvial plains have a decreasing trend,but areas with relatively low risks in flood lake plain plains have an upward trend.Therefore,preventive and protective measures should be taken to ensure the water safety of the masses.（5）Groundwater environmental health risk management and control should adhere to the principle of"Prevention and protection first"and follow the overall idea of"Repair and control high-risk areas.Prevent and protect low-risk areas".Based on local conditions,start with the three elements of risk"control sources-intercept dangerous paths-protect risk receptors",and implement management and control measures at different levels.