Characteristics And The Source Apportionment Of Groundwater Nitrogen Pollution In Weinan Region

Nitrate nitrogen is one of the main pollutants in groundwater,and it has become a worldwide environmental pollution problem.Groundwater nitrogen pollution not only brings environmental pollution,ecological balance destruction,but also threatens human health.Nitrate nitrogen comes from a wide range of sources,even its migration and transformation process in the soil-groundwater system is extremely complex.Weinan region is located in the east of guanzhong plain.It is an important place for industrial and planting in Shaanxi province.However,weinan is an arid and semi-arid region with a high population density,it also has a developed industry and agriculture,this cause a increasingly serious groundwater nitrogen pollution.Therefore,take the groundwater in weinan area as the research object to analyze the nitrogen pollution and it sources will make a lot of sense to control the groundwater nitrogen pollution in this region.In this paper,depending on the national natural science foundation of China?41877190?,based the collecting and analyzing previous research.Using the field survey sampling?health risk assessment?multivariate statistical analysis and the isotope analytical model from Bayesian will provide a support to study the prevention of groundwater nitrogen pollution when we research the pollution characteristics of"Three Nitrogen"?health risks qualitative and quantitative identification of groundwater nitrogen pollution sources.Results are as follows:?1?According to the results of NO₃^-,NO₂^-and NH₄⁺in the groundwater of the study area,the pollution degree of"Three Nitrogen"is:nitrate nitrogen>ammonia nitrogen>nitrogenous nitrogen.The regions with high concentration of NO₃^-were mainly distributed widely.NO₂^-present"low west and high east";NH₄⁺is"low in the north and high in the south".There was a significant negative correlation between the content of NO₃^--N?NH₄⁺-N and groundwater depth.But the content of NO₂^--N is basically unaffected by groundwater depth.?2?The results of the health risk assessment showed that the groundwater"Three Nitrogen"in the study area was safe for the adults and the elderly,but except for kids.The high risk areas of groundwater nitrogen pollution are mainly concentrated in the southeast,west of Fuping county and the south of Pucheng county.?3?Correlation analysis and principal component analysis of groundwater chemical composition show that groundwater in loess tableland can produce HCO₃·SO₄-Na·Mg water type under the influence of mineral leaching.Groundwater in alluvial plain can produce the Cl·SO₄-Na and Cl·SO₄-Na·Mg water type under the influence of evaporation.Groundwater in banks of the river can produce SO₄·HCO₃·Cl-Na·Mg?HCO₃·SO₄-Na·Mg water type under the influence of minerals dissolving.Nitrogen pollution in groundwater is related to agricultural activities and sewage discharge,and alkaline oxidation environment cause the high content of NO₃^-and low of NH₄⁺.?4?From the T/O isotope,groundwater in the study area mainly comes from meteoric water,and its infiltration affected by evaporation.There has a negative correlation from the content of NO₃^--N and the formation age of ground water in Loess tableland and alluvial plain;the content of NH₃-N and the formation age of ground water also have this relationship in banks of the river and alluvial plain.?5?Water chemistry,isotope tracer of N/O and SIAR model indicated that human activities?feces,domestic sewage and nitrogen fertilizer?cause more NO3--N pollution than nature?nitrogen in atmosphere?.The specific data are 74.28%and 25.72%.