摘要
高原湖泊周边浅层地下水作为当地重要的生产和生活水源之一,由于受到地表氮素投入负荷、降雨和灌溉等因素驱动下,浅层地下水NO_(3)^(-)-N污染较为严重,威胁着高原湖泊水质安全.2020~2021年雨季和旱季从云南8个高原湖泊周边农田和居民区的水井中采集了463个浅层地下水样,分析了地下水中氮的污染特征及驱动因素.结果表明,浅层地下水中ρ(TN)、ρ(NO_(3)^(-)-N)、ρ(ON)和ρ(NH_(4)^(+)-N)平均值分别为24.35、15.15、8.41和0.79 mg·L^(-1),8个湖泊周边近32%的浅层地下水样NO_(3)^(-)-N浓度超过地下水Ⅲ类水质要求(GB/T 14848),其中,洱海、杞麓湖和滇池湖泊周边地下水NO_(3)^(-)-N浓度超标率最高,其次是星云湖、阳宗海和异龙湖,最小为抚仙湖和程海.土地利用和季节变化影响着浅层地下水中各形态N浓度及其组成,农田区浅层地下水中各形态N浓度高于居民区,除NH_(4)^(+)-N外,雨季浅层地下水中各形态N浓度高于旱季.NO_(3)^(-)-N是TN的主要形态,占TN的质量分数为57%~68%,ON占TN的质量分数为27%~38%.浅层地下水中EC、DO、ORP和T是反映或影响浅层地下水中各形态N浓度的关键因子,而土壤因子对浅层地下水中各形态N浓度影响较弱.
Shallow groundwater around plateau lakes is one of the important sources of production and potable water.Shallow groundwater NO_(3)--N pollution driven by factors such as surface nitrogen input load,rainfall,and irrigation is serious and threatens the water quality of plateau lakes.In order to identify the characteristics of nitrogen pollution and its driving factors in shallow groundwater,463 shallow groundwater samples were collected from wells in farmland and residential areas around eight plateau lakes of Yunnan in the rainy and dry seasons in 2020 and 2021.The results showed that the average values ofρ(TN),ρ(NO_(3)--N),ρ(ON),andρ(NH_(4)^(+)-N)in shallow groundwater were 24.35,15.15,8.41,and 0.79 mg·L^(-1),respectively.Nearly 32%of the shallow groundwater samples around the eight lakes failed to meet the groundwater ClassⅢwater quality requirements(GB/T 14848)of 20 mg·L^(-1)for NO_(3)--N.Among them,the NO_(3)--N concentration in the shallow groundwater around Erhai Lake,Qiluhu Lake,and Dianchi Lake had the highest rate of exceeding the standard,followed by that around Xingyunhu Lake,Yangzonghai Lake,Yilonghu Lake,Fuxianhu Lake,and Chenghai Lake as the smallest.Land use and seasonal changes affected the concentration and composition of various forms of nitrogen in shallow groundwater.The concentration of various forms of nitrogen in shallow groundwater in the farmland area was higher than that in the residential area.The nitrogen concentration in shallow groundwater in farmland was higher than that in residential areas.Except for NH_(4)^(+)-N,the concentration of various forms of nitrogen in shallow groundwater in the rainy season was higher than that in the dry season.NO_(3)--N was the main nitrogen form in shallow groundwater;the fraction of TN was 57%-68%,and the fraction of ON was 27%-38%.The EC,DO,ORP,and T in shallow groundwater were the key factors reflecting or affecting the concentration of various forms of nitrogen in shallow groundwater,whereas soil factors had a weak impact on the concentra
作者
李桂芳
杨恒
叶远行
陈清飞
崔荣阳
陈安强
张丹
LI Gui-fang;YANG Heng;YE Yuan-hang;CHEN Qing-fei;CUI Rong-yang;CHEN An-qiang;ZHANG Dan(College of Resources and Environment,Yunnan Agricultural University,Kunming 650201,China;Key Laboratory of Mountain Surface Processes and Ecological Regulation,Chinese Academy of Sciences,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences and Ministry of Water Resources,Chengdu 610041,China;Agricultural Environment Resources Institute,Yunnan Academy of Agricultural Sciences,Kunming 650201,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2022年第6期3027-3036,共10页
Environmental Science
基金
国家自然科学基金项目(41977319,42067052)。
关键词
浅层地下水
氮(N)
时空分布
驱动因素
高原湖泊
shallow groundwater
nitrogen(N)
spatiotemporal distribution
driving factor
plateau lake
