地下水环境质量考核点氨氮来源解析方法及应用OA

As a typical pollutant component in aquatic environments,high-concentration ammonium nitrogen has been widely detected in shallow groundwater.However,no consensus has yet been reached regarding its sources.Identifying ammonium nitro-gen sources in groundwater at national assessment sites is an important foundation for carrying out source control of groundwater pollution.This study comprehensively applies multiple methods including field investigations,hydrochemical analysis,multi-iso-tope tracing and principal component analysis(PCA)to conduct source apportionment of ammonium nitrogen in groundwater at national assessment sites of Suzhou City.The results show that:① In the small-scale aquatic environment where the target na-tional assessment site is located,ammonium nitrogen concentrations are generally high in both groundwater and surface water.Af-fected by various controlling factors,both the concentrations and isotopic compositions of ammonium nitrogen in groundwater and surface water exhibit dynamic fluctuation.② Evidence from hydrochemistry and multi-isotopes of ammonium nitrogen and nitrate nitrogen indicates that the primary source of ammonium nitrogen in groundwater at the target national assessment site is the dis-charge of domestic and industrial wastewater.Meanwhile,the application of agricultural nitrogen fertilizers serves as another impor-tant source of ammonium nitrogen in groundwater of the study area.The PCA results based on water quality data corroborate the a-bove conclusions.This study can provide methodological guidance for groundwater pollution source apportionment in small-scale areas at national assessment sites.