Multiple isotopes reveal the driving mechanism of high NO_(3)^(-) level and key processes of nitrogen cycling in the lower reaches of Yellow River  

作　　者：Qianqian Zhang Huiwei Wang Lu Liu Tianlun Zhai Xueqing Zhang 

机构地区：[1]Hebei and China Geological Survey Key Laboratory of Groundwater Remediation,Institute of Hydrogeology and Environmental Geology,Chinese Academy of Geological Sciences,Hebei 050061,China [2]Geo-Environmental Monitoring Institute of Hebei Province,Hebei 050011,China [3]Hebei Provincial Laboratory of Water Environmental Science,Hebei 050037,China [4]Hebei Provincial Academy of Ecological Environmental Science,Hebei 050037,China

出　　处：《Journal of Environmental Sciences》2024年第4期597-606,共10页环境科学学报（英文版）

基　　金：supported by the open Funds of laboratory of water environmental science of Hebei Province,China(No.HBSHJ202103);the Natural Science Foundation of Hebei Province of China(Nos.D2022504015,D2020504001 and D2021504003);the High-level talent Funding project of Hebei Province,China(No.A202101003);the Fundamental Research Funds for the Institute of Hydrogeology and Environmental Geology,Chinese Academy of Geological Sciences(Nos.SK202117 and SK202209);China Geological Survey,China(No.DD20221773)。

摘　　要：The continuous increase of nitrate(NO_(3)^(-))level in rivers is a hot issue in the world.However,the driving mechanism of high NO_(3)^(-)level in large rivers is still lacking,which has limited the use of river water and increased the cost of water treatment.In this study,multiple isotopes and source resolution models are applied to identify the driving mechanism of high NO_(3)^(-)level and key processes of nitrogen cycling in the lower reaches of the Yellow River(LRYR).The major sources of NO_(3)^(-)were sewage and manure(SAM)in the low-flow season and soil nitrogen(SN)and chemical fertilizer(CF)in the high-flow season.Nitrification was the most key process of nitrogen cycling in the LRYR.However,in the biological removal processes,denitrification may not occur significantly.The temporal variation of contributions of NO_(3)^(-)sources were estimated by a source resolution model in the LRYR.The proportional contributions of SAM and CF to NO_(3)^(-)in the low-flow and high-flow season were 32.5%-52.3%,44.2%-46.2%and 36.0%-40.8%,54.9%-56.9%,respectively.The driving mechanisms of high NO_(3)^(-)level were unreasonable sewage discharge,intensity rainfall runoff,nitrification and lack of nitrate removal capacity.To control the NO_(3)^(-)concentration,targeted measures should be implemented to improve the capacity of sewage and wastewater treatment,increase the utilization efficiency of nitrogen fertilizer and construct ecological engineering.This study deepens the understanding of the driving mechanism of high nitrate level and provides a vital reference for nitrogen pollution control in rivers to other area of the world.

关 键 词：NITRATE Driving mechanism Nitrogen cycle Source apportionment TRANSFORMATION Yellow River 

分 类 号：X703[环境科学与工程—环境工程]