西安沣河1986-2009年水质时空变化研究

The Spatio-temporal Change of the Water Quality of Feng River in Xi'an during 1986-2009

利用1986-2009年的水质监测数据和有关的自然社会经济统计数据,采用有机污染综合指数(A值)和变异系数等方法研究了沣河水质近20年的时空变化,并对影响水质变化的自然社会经济因素进行了探讨。研究发现:①沣河近20年的水质变化可分为缓慢污染、快速污染、污染相持和污染改善4个阶段,2000年是水质变化趋势的转折点;②在水质演变的缓慢污染阶段,上游的水质好于中下游;在水质演变的快速污染与污染相持阶段,水质空间差异巨大,表现为从上游至下游污染明显加重;随着污染的改善,2005年以来,上、中、下游监测断面水质的差别大大缩小,2009年四个断面的水质A值分别为2.90、2.97、2.92、2.86;③工业、农牧业、生活污染是影响水质变化的主要因素,与水文气象因素相关性不明显;④大力压缩造纸厂削减工业污染是水质恶化趋势发生逆转的根本原因,同时农牧业、生活污染的迅速上升趋势受到一定遏制;⑤目前流域主要污染源为生活污水、生活垃圾、农牧业等。

Based on the monitoring data of Feng river and some relative statistics of nature,economy and society,the spatio-temporal change rule of the water quality and their coupling relationship with development of society and economy were studied by comprehensive factor（A） of organic pollution and variation coefficient.The results show that： ①During the past 20 years water quality change of Feng river was divided into four phases： slow pollution,accelerated pollution,pollution stalemate and gradual amendment,and 2000 was believed to be the turning point.②Spatial change： in slow pollution stage,water quality of Feng river upper reach was better than that of its midstream and downstream;in accelerated pollution and pollution stalemate stage,water quality was degenerated rapidly from upper reach to downstream;with the gradual amendment of water quality,spatial change of water quality had been greatly reduced since 2005,and in 2009 A values of water quality of four monitoring sections from upper reach to downstream were 2.90,2.97,2.92,2.86 respectively.③Water quality changes was mainly related with the pollution produced by industry of breed livestock and people-living;while there was only a little relationship existed between precipitation and water quality changes.④The great decrease of capacity of paper making was the most important factor which contributed the turning-point of 2000;meanwhile pollution produced by breed livestock and people-living were hold back.⑤At present,the main pollution sources of Feng river are domestic pollution and breed livestock,etc.