摘要
鄱阳湖位于我国农业大省江西省,表层湖水中羟基自由基(HO·)引发的水体光化学反应,可能对流域内的农业污染物—抗生素具有潜在的净化作用.因此,本研究以氙灯模拟太阳光测得鄱阳湖及周边河流羟基自由基表观光量子产率(ΦHO·),在丰水期为(0.57~10.33)×10^(-5),枯水期为(0.45~3.52)×10^(-5).丰水期溶解态有机物(DOM)对HO·形成的贡献率为85.8%~98.7%,枯水期为58.5%~97.6%,表明DOM是HO·形成的主导物质.可能由于水体混合均匀,丰水期除抚河水体可能有其特殊的化学组成外,其它湖泊与河流的水化学组成接近,表现出随溶解态有机碳含量升高,ΦHO·呈先增大后减小的现象.枯水期水体各化学组成含量显著高于丰水期,光屏蔽与淬灭可能起主要作用,只有当NO_2^-含量较高时才显示出对HO·形成的贡献.依据太阳光强可得鄱阳湖丰水期及枯水期表层水HO·的稳态浓度分别为9.51×10^(-16)与4.92×10^(-17)mol·L^(-1),湖水中5种抗生素在HO·作用下的半衰期分别为2.3~13.9 d与44.5~268.7 d,丰水期鄱阳湖表现出更高的光化学净化能力.
Poyang Lake,which located in Jiangxi Province,could play an important role in purifying domestic antibiotic pollutants by hydroxyl radicals（ HO·） formed in surface waters through photochemical reactions.The present study showed that the apparent quantum yields of hydroxyl radical（ ΦHO·）in Poyang Lake as well as its surrounding rivers were estimated to be（ 0.57 - 10.33） ×10-（-5） in wet season and（ 0.45 - 3.52） ×10-（-5） in dry season,and the dissolved organic matter（ DOM） contribute 85.8% - 98.7% and 58.5% - 97.6% to the formation of HO·in wet and dry seasons respectively,suggesting that DOM was the main source of HO·. In wet season,the chemical properties in sampling sites were similar except for Fu River,probably due to the strengthened hydrodynamic connectivity between different water bodies.With the increase of dissolved organic carbon,ΦHO· was firstly increased and then decreased.In dry season,significantly higher levels of dissolved chemicals were obtained,which primarily presented strong light screening and radical quenching effects towards HO·.While the contribution of NO2-- to HO·could only been observed at high NO2-- levels.The averaged steady concentrations of HO·in Poyang Lake was estimated to be 9.51×10-（-16） and 4.92×10-（-17） mol·L-1 in wet and dry seasons according to ΦHO· and intensity of solar irradiation,respectively.Hence,the half-lives of five antibiotics in Poyang Lake were evaluated to be 2.3 - 13.9 and 44.5 - 268.7 days attributed to the degradation by HO·,indicating the higher efficient purification of antibiotics pollutants in Poyang Lake during wet season.
作者
肖远东
彭维维
安琦
蔡悦
朱韻洁
黄华军
方汉孙
XIAO Yuandong;PENG Weiwei;AN Qi;CAI Yue;ZHU Yunjie;HUANG Huajun;FANG Hansun(College of Land Resource and Environment,Jiangxi Agricultural University,Nanchang 330045;Key Laboratory of Poyang Lake Basin Agricultural Resource and Ecology of Jiangxi Province,Jiangxi Agricultural University,Nanchang 330045)
出处
《环境科学学报》
CAS
CSCD
北大核心
2018年第8期2965-2973,共9页
Acta Scientiae Circumstantiae
基金
国家自然科学基金青年基金项目(No.21607065)
江西省自然科学基金青年基金项目(No.20151BAB213036)~~
关键词
鄱阳湖
羟基自由基
自然净化
抗生素
Poyang Lake
hydroxyl radical
natural purification process
antibiotics
