Risk Assessment Of Shallow Groundwater Pollution In Shenbei

Groundwater is a strategic resource to support the sustainable development of economy and environment.The shallow groundwater is an important source of drinking water in many suburban and rural areas.The influence of urban expansion and agricultural intensive development on the groundwater has been becoming more and more obvious.Groundwater pollution threatens the safety of ecosystem and the health of the residents.To carry out pollution levels,spatial distribution,regional ecological and human health risk assessment,selecting a typical study area,has important theoretical significance and practical value for guiding the optimization land use pattern and groundwater environment management in the process of urban expansion and agriculture intensive development.In this dissertation,Shenbei district of Shenyang city was taken as a case study,I evaluated comprehensively pollution degree,spatial characteristics,regional ecological risk and human health risk groundwater by sampling and test,statistical analysis,modeling analysis.The main conclusions are as follows: 1)the water quality of shallow groundwater in Shenbei district is better in general.Nitrate,nitrite,Fe,Mn,Cd,Pb,Hg,As,Cr6+,BHC,DDT and PAHs appeared in each sampling site,Nitrate,nitrite,Fe,Mn and Cd exceed 35%,12%,46%,76% and 19% of the limited value,respectively.2)Nitrate,Fe and Mn have strong spatial variability;their spatial heterogeneities are mainly affected by the structural factors such as natural conditions.Cd,Pb and Hg have medium spatial variability.As,BHC,DDT and PAHs have weak spatial variability.Spatial heterogeneity of Cd,Pb,Hg,As,BHC,DDT and PAHs is mainly affected by random factors of human activities like urbanization,industrialization and agricultural intensivedevelopment.3)Spatial distribution of groundwater intrinsic vulnerability shows descending gradient from northwest to southeast.I found that Shifosi and Xinglongtai towns in west part and Daoyi,Xinchengzi and Huangjia towns in middle part of of shenbei district have higher ecological risk through overlapped and analyzed of risk sources,comprehensive pollution index and intrinsic vulnerability.4)Shallow groundwater in most areas of Shenbei district has no health risks from drinking exposition.Carcinogenic hazard exceeding the acceptable rangeexists only in local intensive developed farms like Qianjin farm.5)Groundwater risk management in the area should be focusd on nitrate,Fe and Mn which exceeded the limit value and the BHC and PAHs which have potential risks.Spatial land use should control the expansion scale of urbanization and agricultural intensive development.It is important for groundwater quality to strengthen the management of emissions of pollutants in the process of social economic development.