Nitrogen Pollution And Its Health Risk Assessment Of Surface Water And Groundwater In A Typical Arable Zone In Huaibei Plain

The research object about this paper is the surface and ground water of thesurrounding farmland irrigation area in the Chezhegou control drainage zone in LixinCounty, situated in Anhui Huaibei Plain (China). There are6sampling sites,14observation wells and13farmers’ wells were chosen to conduct monitoring and analysisthroughout the year.Through correlation analysis, cluster analysis and variance analysisto investigate the effect of controlled drainage on groundwater nitrogen andphosphorus pollution. And then, its health risks were evaluated for the study areas. Theconclusion of this study are mainly the following:（1）Variable coefficient of nitrogen and phosphorus in three kinds of water is large,it shows that with the sampling points in the distribution of the nitrogen and phosphorusspatial heterogeneity is stronger.The level of nitrogen in observation wells and farmers’wells is NO3-N﹥NH4-N﹥NO2-N. Farmers well water and farmland of NO3-N contentin groundwater is higher than surface water, the ditch and two types of undergroundwater in NO2-N and NH4-N content below the surface. In this paper, the level of the TPand SRP in the surface and ground water is both low. The impact of nitrogen andphosphorus content in farmland groundwater by the seasonal changes is obvious,presents the summer to winter decreasing and then increasing trend（2）Through correlation analysis found that Chezhegou water environmental factorsis strong, but farmland water environment factors of groundwater and farmers wellcorrelation is weak. By the cluster analysis can be found that the nitrogen andphosphorus content of the farmland ground water is associated with the distance ofChezhegou, the distance is closer, the level is lower.（3）To analyze the changing trend of surface water TN/TP ratio all the year round,we can see that, most of the time, Chezhegou surface water condition is in a state ofnitrogen limitation, just four months in the phosphorus limit state. The level of TN/TP infarmland water groundwater is largest,and Chezhegou is lowerst.（4）The eutrophication degree at six sampling from strong to weak is Chezhegou＞Jiangnanqiao＞Yangbanqiao＞Baxia＞Yanhuqiao＞Wanglaojia. The values of hazardindexes for oral and dermal exposure paths are far below the accepted threshed value1.0. The risk of various forms of nitrogen is NO3-N﹥NO2-N﹥NH4-N.