水文地质工程地质2026，Vol.53Issue(1)：80-94,15.DOI:10.16030/j.heg.202502081
赣江下游地下水三氮源解析及其对极端降水-干旱的响应
Source apportionment of three nitrogen species in groundwater and their response to extreme precipitation-drought in the lower Ganjiang River
摘要
Abstract
Extreme climate events have a significant impact on groundwater quality.However,the sources of the"three nitrogen species"(ammonia nitrogen,nitrite nitrogen,and nitrate nitrogen)and their responses to hydrogeochemical processes under such conditions remain insufficiently understood.Particularly under extreme precipitation and drought conditions,the spatiotemporal distribution characteristics and source apportionment of the"three nitrogen species"have not been sufficiently explored.This study focuses on the groundwater in the downstream area and the southern branch region of the Ganjiang River Basin in Jiangxi Province.Samples were collected to analyze the hydrogeochemical characteristics under extreme climatic conditions.The Positive Matrix Factorization(PMF)model was employed to identify the sources of the"three nitrogen species".The study compared the concentration changes,spatial-temporal distribution,source contributions,and response mechanisms of the"three nitrogen species"under extreme precipitation and drought conditions.The results indicate that extreme climate events significantly impact the groundwater levels and redox environments in the lower Ganjiang River.During extreme drought,groundwater levels decline substantially and Eh values decrease,indicating a more reduced environment.The groundwater is characterized by an HCO3-Ca type,with enhanced variability of different ions during both extreme precipitation and drought periods.During extreme precipitation,NH4+-N concentrations decrease,while NO3--N concentrations increase in the downstream direction.In contrast,during extreme drought,NH4-N and NO--N concentrations rise significantly.Source apportionment using Positive Matrix Factorization(PMF)reveals that dissolution of salts(e.g.,gypsum,magnesium salts),soil nitrogen transformation(e.g.,nitrification and denitrification),and human activities(e.g.,agricultural practices,domestic sewage discharge,and industrial wastewater emissions)are the primary sources of NH4-N,NO--N,and NO3--N,respectively.Extreme climate events significantly alter the contribution rates of these sources.Under extreme climate conditions,the variations in nitrogen compounds in groundwater are closely related to hydrogeochemical processes.During extreme drought,enhanced evaporation and concentration lead to the accumulation of NH4-N.In contrast,during extreme precipitation,dilution by precipitation recharge causes an increase in NO3--N and a decrease in NO2--N.This study elucidates the sources of the"three nitrogen"in groundwater and their hydrogeochemical response mechanisms under extreme climate conditions,providing theoretical support for regional groundwater pollution control and water resource management.关键词
极端降水/极端干旱/地下水/三氮/赣江流域Key words
extreme precipitation/extreme drought/groundwater/tri-nitrogen/Ganjiang River basin分类
天文与地球科学引用本文复制引用
赵崇桢,储小东,陈婷,马文洁,高柏..赣江下游地下水三氮源解析及其对极端降水-干旱的响应[J].水文地质工程地质,2026,53(1):80-94,15.基金项目
江西省技术创新引导类计划项目(2023KDG01009) （2023KDG01009）
国家自然科学基金项目(42272301) （42272301）
