近25年洞庭湖水质演变趋势及下降风险  

The trend and downside risk of water quality evolution in Dongting Lake in recent 25 years

作　　者：林日彭 倪兆奎 郭舒琨[2,3,4] 龚佳健 王圣瑞 LIN Ri-peng;Ni Zhao-kui;GUO Shu-kun;GONG Jia-jian;WANG Sheng-rui(Key Laboratory of Poyang Lake Environment and Resource Utilization,Ministry of Education,School of Resources Environmental & Chemical Engineering,Nanchang University,Nanchang330031,China;College of Water Sciences,Beijing Normal University,Beijing 100875,China;Chinese Research Academy of Environmental Sciences,Beijing 100012,China;College of Hydraulic & Environmental Engineering,China Three Gorges University,Yichang 443002,China)

机构地区：[1]南昌大学资源环境与化工学院鄱阳湖环境与资源利用教育部重点实验室,江西南昌330031 [2]北京师范大学水科学研究院,北京100875 [3]中国环境科学研究院,北京100012 [4]三峡大学水利与环境学院,湖北宜昌443002

出　　处：《中国环境科学》2018年第12期4636-4643,共8页China Environmental Science

基　　金：国家科技支撑计划课题(2014BAC09B02);万人计划项目(312232102)

摘　　要：利用1991～2015年水质数据研究了洞庭湖水质演变特征,识别了主要驱动因子,并探讨了水质下降对其生态风险影响.结果表明,1991～2015年间,洞庭湖水质总体呈下降趋势,TN和TP是影响水质变化的主要指标,其浓度年均值分别介于1.060～2.072mg/L和0.026～0.146mg/L;其中,1991～2002年间,TN和TP浓度均显著上升,多元回归分析显示水位和泥沙淤积是导致洞庭湖TN和TP浓度升高的主要因素; 2003～2015年间,TN浓度进一步明显上升,而TP浓度维持高位,波动变化,氮、磷负荷输入量和水位是影响TN和TP浓度变化的主要因素.洞庭湖生态风险等级则由轻微风险转变为中等风险,TP是影响生态风险的主要水质指标;受洪水、农业面源污染和城市化等影响,洞庭湖磷风险时空差异较大,1991～2008年间,各湖区磷风险均有所升高,其中西洞庭湖磷风险增长幅度最大;2009～2015年,各湖区磷风险均有所降低,其中西洞庭湖下降幅度最大,而东洞庭湖下降幅度较小.因此,进一步控制入湖氮磷负荷、优化水位及重点关注磷风险是保护洞庭湖水生态的重要举措.The evolution characteristics of water quality and major driving factors were investigated by using the data from1991to2015in Dongting Lake.The effects of declining of water quality on aquatic ecological risks also discussed in this study.The results showed that the water quality declined from1991to2015.TN and TP were the major indexes that caused water quality decline,with the concentrations ranged from1.06~2.07and0.026~0.146,respectively.From1991to2002,the concentrations of TN and TP increased significantly,which could be the effects of water level and sedimentation according to the multiple regression analysis.From2003to2015,TN concentration continuous to increase but TP was relatively stable,which resulted from nitrogen and phosphorus load input and water level.The level of ecological risk of Dongtimg Lake transformed from slightly to moderately from1991to2015.The flood and enhanced agricultural nonpoint source pollution and urbanization were the main drivers,from1991~2008,the risk all increased in different,especially in western district of Dongting Lake.From2009to2015,the risk in different regions declined,the decrease of eastern district were more significant than western district.Therefore,to protect aquatic ecosystem of Dongting Lake,optimization of hydrologic condition,control of nutrients loading and particular focus on P risk were the most important strategies.

关 键 词：洞庭湖水质演变 驱动因子 磷风险 TN和TP 

分 类 号：X524[环境科学与工程—环境工程]