店埠河流域地表水氮素时空分布和来源解析  

Spatio-temporal Distributions and Source Analysis of Nitrogen in the Surface Water of Dianbu River Basin

作　　者：秦先燕[1] 吴剑雄[1] 郑涛 彭苗枝[1] QIN Xian-yan;WU Jian-xiong;ZHENG Tao;PENG Miao-zhi(Geological Survey of Anhui Province(Anhui Institute of Geological Sciences),Hefei 230001,China)

机构地区：[1]安徽省地质调查院(安徽省地质科学研究所),合肥230001

出　　处：《环境科学》2024年第12期7100-7110,共11页Environmental Science

基　　金：安徽省重点研究与开发计划项目(202104i07020005)。

摘　　要：店埠河是巢湖西半湖入湖河流中污染最严重的河流之一,氮素是主要的影响因子之一.以丰水期、平水期和枯水期采集的30个地表水样品为研究对象,结合水化学分析方法,运用硝酸盐δ^(15)N和δ^(18)O同位素、铵盐δ^(15)N同位素和SIAR混合模型,分析氮素时空分布特征及其影响因素,解析硝酸盐和铵盐来源.结果表明,店埠河流域地表水TN和NH_(4)^(+)-N污染状况较重,尤其在枯水期.沿着干流,TN和NO_(3)^(-)-N浓度从上游到下游主要呈现先上升再下降(丰水期和平水期),或上升趋势(枯水期),主要受土地利用类型影响.地表水中δ^(15)N-NO_(3)^(-)和δ^(18)O-NO_(3)^(-)值范围分别是-4.61‰~24.39‰和-5.39‰~^15.18‰,主要分布在化肥、土壤有机氮以及粪肥污水区间.在不同水文期,上游化肥(34.53%~52.39%)和土壤有机氮(26.24%~32.29%)为硝酸盐主要来源,中下游硝酸盐来源贡献率大小顺序为:粪肥污水>土壤有机氮>化肥>大气降水.δ^(15)N-NH_(4)^(+)均值为-3.97‰,铵态氮肥和大气降水是铵盐的主要来源.研究结果能为流域水环境综合治理提供科学依据.Dianbu River,flowing into the western part of Chaohu Lake,has been heavily polluted,and nitrogen is one of the key factors.During three periods(wet,normal,and dry),30 surface water samples were collected from the Dianbu River Basin as the research objects.The water chemistry,multiple stable isotopes(δ^(15)N-NO_(3)^(-),δ^(18)O-NO_(3)^(-),andδ^(15)N-NH_(4)^(+)),and a SIAR mixing model were analyzed not only to understand the spatio-temporal distribution characteristics of nitrogen and its influencing factors but also the sources of nitrogen.The results showed that the concentrations of TN and NH_(4)^(+)-N were higher in dry periods than those in wet and normal periods.Compared with the water quality requirements(GB/T 14848),56.67%of samples in the surface water TN were in the situation of GradeⅤ-inferior Grade V.The proportion ofⅣ-inferiorⅤof NH_(4)^(+)-N sections was 10%.Along the main river,the concentrations of TN and NO_(3)^(-)-N mainly increased and then decreased(in the wet season and normal season)or increased(in the dry season)from upstream to downstream,mainly affected by precipitation,land use types,etc.The ratios ofδ^(15)N-NO_(3)^(-)andδ^(18)O-NO3 ranged from-4.61‰to 24.39‰and from-5.39‰to 15.18‰,respectively,suggesting the multiple sources of fertilizer,soil organic nitrogen,and manure sewage.Essentially,slight denitrification was observed in surface water.Based on the SIAR model,in different hydrological periods,fertilizer(34.53%-52.39%)and soil organic nitrogen(26.24%-32.29%)were the major sources of nitrate in the upper basin.Manure sewage(30.10%-37.93%)was the primary source of nitrate in the middle and lower reaches of the Dianbu River Basin,followed by soil organic nitrogen(28.78%-31.21%),fertilizer(25.89%-28.11%),and precipitation(4.36%-11.92%).The ratio ofδ^(15)N-NH_(4)^(+)in surface water during the wet period ranged from-9.16‰to 2.48‰,mainly indicating that the sources of ammonium salt were ammonium nitrogen fertilizer and precipitation.This study will provide a useful

关 键 词：巢湖 河水 氮氧同位素 铵盐氮同位素 硝化作用 SIAR混合模型 

分 类 号：X522[环境科学与工程—环境工程]