洱海上覆水溶解性有机氮特征及其与湖泊水质关系  

Characteristics of dissolved organic nitrogen(DON) and relationship with water quanlity in the overlying water of Erhai lake

作　　者：李文章[1,2,3,4] 张莉[2,3,4] 王圣瑞[1,2,3,4] 肖尚斌[1] 李艳平[2,3] 钱伟斌[2,3,5] 李秋材 席银 

机构地区：[1]三峡大学,水利与环境学院,湖北宜昌443002 [2]中国环境科学研究院,环境基准与风险评估国家重点实验室,北京100012 [3]中国环境科学研究院,国家环境保护湖泊污染控制重点实验室,北京100012 [4]云南省高原湖泊流域污染过程与管理重点实验室,云南大理671000 [5]桂林理工大学环境科学与工程学院,广西桂林541004

出　　处：《中国环境科学》2016年第6期1867-1876,共10页China Environmental Science

基　　金：国家自然科学基金(U1202235,41503113);国家水专项“十二五”课题“洱海湖泊生境改善关键技术与工程示范”(2012ZX07105-004);环境基准与风险评估国家重点实验室自由探索项目(2014-GOT-042-N-06);重点实验室开放基金资助

摘　　要：研究了洱海上覆水溶解性有机氮（DON）含量及空间分布,利用三维荧光和紫外光谱技术分析了其结构组分特征,探讨了DON与湖泊水质间关系.结果表明：2014年洱海上覆水DON含量在0.08~0.33mg/L之间,全年平均为0.18mg/L,时间分布为春季〉夏季〉秋季〉冬季,空间分布呈南部〉北部〉中部的趋势,垂向分布呈中层〉表层〉底层的趋势.洱海上覆水DON腐殖化程度较高,取代基中羰基、羧基、羟基、酯等含量较少,主要以脂肪链为主;自生源指数（BIX）在0.84~1.19之间（平均值0.94）,荧光指数FI值在1.58~1.66之间（平均值为1.63）,表明洱海上覆水DON受陆源输入和内源生物代谢共同影响;另外,洱海上覆水DON主要组分为腐殖质类物质（平均61.82%）,且在0~2m各荧光组分转化量最大,其类蛋白成分P（I＋II,n）始终小于20%.洱海上覆水DON和溶解性总氮（DTN）呈极显著正相关（R=0.949,P〈0.01）,类蛋白物质与类腐殖质比值（P_（I＋II,n）/P_（III＋V,n））与TN、DTN和SRP呈显著正相关（R=0.467~0.552,P〈0.05）,表明上覆水DON含量在一定程度上可以指示洱海水质状况,特别是其类蛋白物质含量能较好的指示其水质状况,即类蛋白物质含量越高,上覆水体氮磷含量越高.This study investigated the content and spatial distribution of dissolved organic nitrogen （DON） in the overlying water of Erhai Lake. 3D fluorescence and UV-vis absorbance techniques were utilized to analyse its structure composition characteristics. The relationship between DON characteristics and water quality was also discussed in detail. DON contents in the overlying water ranged from 0.08 to 0.33mg/L （average value of 0.18）, with the temporal distribution of the spring〈 summer〈 autumn〈 winter, in the year of 2014. The spatial and vertical DON distributions followed the pattern of southern〈northern〈middle and middle layer〈surface layer〈bottom layer, respectively. Besides, DON humification degree in the overlying water of Erhai lake was high, with DON being mainly composed of aliphatic chain instead of carbonyl, carboxyl, hydroxyl substituents and ester content. The BIX and FI values ranged from 0.84 to 1.19（mean value of 0.94） and 1.58 to 1.66（mean value of1.63）,respectively, indicating that DON in the overlying water of Erhai lake was affected by terrigenous input and biological endogenous metabolism. Additionally, the study exhibited that the humic acid-like substances, which accounted for 61.82% averagely, were the main DON component. The fluorescent components at 0~2m presented the maximum Migration quantity, with the protein-like components （P（I＋I,n）） always below 20%. Moreover, DON had a significant positive correlation with DTN in the overlying water of Erhai Lake （R=0.949,P＆lt; 0.949）, and P（I＋I,n）/P（II＋V,n） values exhibited a significant positive correlation with TN, DTN and SRP （R=0.467~0.552,P＆lt;0.05）. This suggested that the DON content could indirectly reflect Erhai lake water quality to a certain extent. Especially the protein-like substances positively contributed a lot to the maintenance of good water quality, namely the higher the protein-like substance content was, the higher the nitrogen and phosphorus content would be in the

关 键 词：洱海 上覆水 溶解性有机氮 三维荧光 FRI 

分 类 号：X524[环境科学与工程—环境工程]