奎河河水入渗对河岸带地下水氨氮和硝酸盐氮浓度的影响

为研究不同水文期河水与河岸带地下水的水量补给关系，以及河水中的氮污染物对河岸带近岸地下水水质的影响，选取了安徽省宿州市杨庄乡的奎河断面作为研究对象，基于氢氧同位素示踪技术、末端元混合模型、Pearson相关性分析和多元线性回归方法，分析河水、上游潜水等补给源对近岸含水层的ρ（NH₄+-N）和ρ（NO₃--N）的影响，并构建河岸带地下水氮浓度预测模型.结果表明:①平水期至丰水期期间河水与地下水的补给来源主要为大气降水，河水始终补给河岸带地下水，其中，河水对潜水层及弱承压层的补给率分别为10.87%~49.74%和0~19.78%.②空间分布上，ρ（NH₄+-N）和ρ（NO₃--N）均表现为河水>近岸潜水>近岸弱承压水，且在地下水中均呈现由河流向两岸递减的关系.③近岸潜水层与弱承压层的ρ（NH₄+-N）均随着河水和上游潜水ρ（NH₄+-N）贡献量的增加而升高，近岸潜水层的ρ（NO₃--N）随着河水和上游潜水ρ（NH₄+-N）贡献量的增加而升高.④相比于ρ（NO₃--N），多元线性回归模型更能准确地预测近岸潜水层与弱承压层ρ（NH₄+-N）在ORP、ρ（DO）、河水ρ（NH₄+-N）贡献量，以及上游潜水ρ（NH₄+-N）和ρ（NO₃--N）贡献量综合影响下的变化趋势.研究显示，河水与上游潜水的线性混合是造成河岸带地下水氮污染的重要途径，河流氮污染防治措施将为河岸带地下水水质提供重要保障. 

Effects of Kuihe River Infiltration on the Concentration of Ammonia Nitrogen and Nitrate Nitrogen in Groundwater of Riparian Zone

In order to detect the recharge relationship between river water and groundwater in the riparian zone, and effects of river nitrogen pollutants on the quality of groundwater in the riparian zone of the Kuihe River in Yangzhuang Township, Suzhou City, Anhui Province, was selected as the research area. Based on hydrogen and oxygen isotope tracing technology, linear end member mixing model, Pearson correlation analysis, and multiple linear regression, the effects of recharge sources such as river water and upstream phreatic layer on ρ(NH₄+-N) and ρ(NO₃--N) in the coastal aquifers were studied, and the prediction model of groundwater nitrogen concentration in riparian zone was established. The results showed that:(1) River water and groundwater were mainly recharged by precipitation during average flow period and high flow period. River water always recharged groundwater in the riparian zone, with the river water accounting for 10.87%-49.74% and 0-19.78% in the phreatic layer and weak confined aquifer respectively. (2) In spatial distribution, ρ(NH₄+-N) and ρ(NO₃--N) in river water was higher than that in phreatic layer and weak confined aquifer, and ρ(NH₄+-N) and ρ(NO₃--N) in groundwater showed a decreasing relationship from river to both banks. (3) The ρ(NH₄+-N) of the nearshore phreatic layer and weak confined layer increased with the raise of ρ(NH₄+-N) provided by river water and upstream phreatic water, and ρ(NO₃--N) of the nearshore phreatic layer also increased with the increasing of ρ(NH₄+-N) provided by river water and upstream phreatic water. (4) Compared with ρ(NO₃--N), multiple linear regression model could more accurately predict the variation of ρ(NH₄+-N) in the nearshore phreatic layer and weak confined layer under the comprehensive effects of ORP, ρ(DO), river water ρ(NH₄+-N) contribution, upstream phreatic layer ρ(NH₄+-N) and ρ(NO₃--N) contribution. Therefore, the linear mixing of river water and upstream phreatic water is an important process causing groundwater nitrogen pollution in riparian zone, and control measures of nitrogen pollutants in rivers would provide important guarantee to protect groundwater quality in riparian zone.