湘江干流水环境质量演变特征及其关键因素定量识别

为科学有效地保护湘江流域水环境，定量识别湘江干流主要水质指标的驱动因素，该研究基于1990~2016年水质监测数据及沿岸永州 长沙五市社会经济发展指标，采用Mann-Kendall检验法分析湘江干流水环境演变趋势，通过逐步回归分析确定各地区各水质指标主要驱动因素。结果表明：湘江干流COD_Mn、Cd、As整体呈下降趋势，上游BOD₅呈下降趋势，上中游NH₃-N呈上升趋势，中游衡阳、株洲市重金属Cr⁶⁺呈上升趋势，衡阳市TP呈上升趋势，中下游BOD₅呈上升趋势；定量追溯各水质指标影响因素得出工业污染是湘江干流重金属As、Cr⁶⁺、Cd主要驱动因素，永衡株潭地区NH₃-N，衡阳市BOD₅、COD_Mn、TP及衡株潭地区BOD₅均以农业污染影响为主；发现产业结构调整对干流水环境有显著影响，建议在流域产业结构调整过程中加强转型升级。

The Evolution Features of Water Environmental Quality and Quantitative Identification of Key Factors on Xiangjiang River

In order to protect the water environment of Xiangjiang River scientifically and effectively, and quantitative identify the main driving factors of water quality. In this paper, the Mann Kendall was used to analyze the water environment evolution trend of Xiangjiang river trunk stream, the stepwise regression analysis methods were used to determines the main driving factors of water quality indexes in different regions, which is based on water quality monitoring data from 1990 to 2016 and socioeconomic development indicators of cities along the coast. The results show that COD_Mn, Cd and As was downtrend, BOD₅ shows an downtrend in the upper reaches, the pollution of NH₃-N in the upper and middle reaches shows an upward trend,TP in Hengyang shows an upward trend, in the middle reaches of Hengyang and Zhuzhou regions, heavy metal Cr⁶⁺ shows an increasing trend, BOD₅ in the middle and lower reaches shows an increasing trend; It is concluded that industrial pollution is the main driving factor of heavy metals As, Cr⁶⁺and Cd in Xiangjiang River trunk stream. NH₃-N in Yong Heng Zhu Tan, BOD₅, COD_Mn, TP in Hengyang and BOD₅ in Heng Zhu Tan are mainly affected by agricultural pollution; it is found that the industrial structure adjustment has a significant impact on the water environment, it is suggested to strengthen the transformation and upgrading in the process of industrial structure adjustment in the basin.