鄱阳湖出流长序列代表性水质指标变化及其驱动力

Changes of representative water quality indicators and their driving forces in long sequence of outflow in Poyang Lake

探究湖泊出流水体水质变化及其驱动力对湖泊水环境管理与保护具有重要意义。基于鄱阳湖出口蛤蟆石段长时间序列28 a(1991~2018年)的水质资料,利用水质指数法(Water Quality Index,WQI)来评估鄱阳湖出流水体水质状况,并采用Mann-Kendall检验法分析水质指标多年变化趋势。同时,通过灰色关联度分析法识别了影响鄱阳湖出流水体水质变化的关键驱动因子。结果表明:①总体上,鄱阳湖出流水体水质良好,WQI总变化范围为7.00~27.65。②水体中溶解氧(Dissolved Oxygen,DO)呈下降趋势,趋势不明显,高锰酸盐指数(Permanganate Index,COD_(Mn))和氨氮(Ammonia Nitrogen,NH 3-N)呈显著增加趋势,其统计值Z分别为2.53和3.93;WQI总呈显著上升趋势,统计值Z为4.27。③鄱阳湖出流水体水质变化的主要驱动因子为人口、地区生产总值、第三产业产值、粮食总产量等。研究成果可为鄱阳湖水环境管理与保护提供一定借鉴。

Exploring the water quality changes of lakes outflow and their driving forces are of great significance to the management and protection of lake water environment.Based on the water quality data of the Hamashi Section in Poyang Lake s outflow in the past 28 years(1991~2018),we used the Water Quality Index(WQI)method to assess the water quality of Poyang Lake outflow,and used the Mann-Kendall test method to analyze the change trend of the water quality indicators.At the same time,the key driving factors affecting the changes in the water quality of Poyang Lake s outflow were identified by the grey relational analysis method.The result showed that:in general,the water quality of Poyang Lake s outflow was good,and the total WQI index varied from 7.00 to 27.65.Dissolved Oxygen(DO)in the water body showed a decreasing trend,but the trend was not obvious.Concentration of Permanganate Index(COD_(Mn))and Ammonia Nitrogen(NH_(3)-N)showed a significant increasing trend,and their statistical values Z were 2.53 and 3.93 respectively.The total WQI showed a significant increasing trend,and its statistical value Z was 4.27.In the 1991~2018,the main driving factors for the changes in the water quality of Poyang Lake s outflow were population,regional GDP,tertiary industry and total grain output.The study results can provide a reference for the water environment and protection of Poyang Lake.