摘要
了解城市内湖水中胶体的环境行为对研究湖泊水环境中污染物的迁移转化意义重大.微生物降解及自团聚过程是湖泊水体中胶体转化的重要途径,然而目前有关不同粒径胶体在微生物降解及自团聚作用下荧光特性变化的报道还非常少.基于此,本文选取南昌市内最大的湖泊(瑶湖)及其支流水体,通过切向超滤技术、三维荧光光谱法及平行因子分析法(PARAFAC),分析了在灭菌及微生物存在下两种水样含不同粒径胶体的水体(即W原水、W 1μm、W 0.45μm和W 1 kDa)中荧光特性的变化情况.通过PARAFAC模型共解析出3个类腐殖质组分(C1~C3)和1个类蛋白质组分(C4).初始时刻所有水样均以类腐殖质组分含量更高,且大都集中在1 kDa^0.45μm粒径胶体中.两种水样荧光物质的减少为微生物降解及自团聚作用共同主导,自团聚作用约占50%.相较于小粒径(W 1 kDa)胶体,微生物降解对大(W原水)、中(W 1μm)粒径胶体中荧光物质减少的影响更大.此外,类蛋白物质主要以微生物降解占主导,并出现类蛋白物质从大粒径向小粒径胶体转移的现象;而类腐殖物质的降解以自团聚作用为主,并出现类腐殖物质由小粒径向大粒径胶体的转移.
Fate of colloids in urban lakes is of great significance for understanding the migration and transformation of contaminants in the lake water environment.Microbial degradation and self-assembly are the main ways for the degradation of colloids in lake water.However,until now,few studies were focused on the degradation of size-dependent fluorescent properties of colloids under these two processes.In this study,water samples from the largest lake in Nanchang City(i.e.Lake Yaohu,namely L sample)and one of its tributaries(namely R sample)were collected.Combined cross-flow ultrafiltration and three-dimensional excitation-emission matrix fluorescence spectroscopy,this study investigated the degradation of fluorescent properties in different sizes of colloids in water(i.e.the original sample,<1μm,<0.45μm and<1 kDa sample)from L and R sample with and without microorganisms.Based on the parallel factor analysis,three humic-like fluorescence components(C1-C3)and one protein-like fluorescence component(C4)were identified.In the initial water sample,both L and R samples show higher fluorescence intensity for the humic-like fluorescence components,and most of which are concentrated in the small-size(1 kDa-0.45μm)of colloids.The reduction of fluorescence substance in L and R samples was dominated by microbial degradation and self-assembly with self-assembly contributing nearly 50%.Compared to the soluble phase(<1 kDa),the effect of microbial degradation on the reduction of fluorescence components was higher in the medium-(<1μm)and large-(the initial sample)size of water.Overall,protein-like substances,preferentially decomposed by microorganisms,are transferred from the large size of colloids to the small size of colloids;while humic-like substances,degraded dominantly by hydrolysis,are transferred with the opposite way from the small size of colloids to the large size of colloids.
作者
黄娴
聂明华
丁明军
晏彩霞
刘慧慧
吕泽兰
HUANG Xian;NIE Minghua;DING Mingjun;YAN Caixia;LIU Huihui;LV Zelan(Key Laboratory of Poyang Lake Wetland and Watershed Research,Ministry of Education,School of Geography and Environment,Jiangxi Normal University,Nanchang 330022,P.R.China)
出处
《湖泊科学》
EI
CAS
CSCD
北大核心
2020年第6期1695-1706,共12页
Journal of Lake Sciences
基金
国家自然科学基金项目(42067034,42067058)
江西省自然科学基金项目(20202BAB203015,20202BAB203014)联合资助.
关键词
微生物降解
自团聚
胶体
荧光特性
粒径
瑶湖
Microbial degradation
self-assembly
colloids
fluorescence
particle sizes
Lake Yaohu
