三峡库区支流澎溪河回水区水质调查与评价

Water Quality Survey and Evaluation in the Backwater Area of the Pengxi River in the Three Gorges Reservoir

澎溪河为三峡库区北岸最大支流.自2004年三峡水库蓄水以来已多次暴发水华.为了科学全面评价澎溪河回水区水质状况和分析其富营养化成因,本研究在2007年至2009年对澎溪河回水区水质进行了监测,并采用《中国地表水环境质量标准(GB3838-2002)》和卡森指数法对澎溪河水质进行富营养化状况评价.研究结果表明:澎溪河水体中总氮(TN)、总磷(TP)浓度较高,全年都呈现富营养水平或者重度富营养水平,双江大桥附近水体富营养状况与高阳渡口、渠马渡口的相比较为严重;TN浓度、溶解氧(DO)浓度随季节变化趋势不明显;TP浓度、叶绿素a(Chla)浓度和透明度(SD)随季节变化趋势明显,TP和Chla夏秋季高、春冬季低,而SD则相反.水体中TP浓度是影响澎溪河水体发生富营养化的主要因素.水体总磷主要来自面源污染.

Since the first impoundment of the Three Gorges Reservoir in 2004,algal blooms have broken out for several times in the Pengxi River,the largest tributary on the north shore of the reservoir area.In order to evaluate water quality in the backwater area of the Pengxi River and analyze the causes of eutrophication,water quality in the backwater area of the Pengxi River was monitored from 2007 to 2009 and evaluated based on Environmental Quality Standards for Surface Water（GB3838-2002） of China and Carlson Trofic State Index.It was found that the concentrations of total nitrogen（TN） and total phosphorus（TP） in the Pengxi River were high and eutrophication or serious eutrophication of the water body was detected all the year round.The situation in Shuangjiang Bridge Ferry was more serious than that in Gaoyang and Quma Ferries.Concentrations of TN and dissolved oxygen（DO） showed no obvious trend of variation with seasons,while the concentration of TP,chlorophyll a（Chla） and secchi depth（SD） exhibited a pronounced seasonal fluctuation.In addition,concentration of TP and Chla in summer and fall were higher than in winter and spring,while SD showed an opposite tendency.According to this study,the concentration of TP is the major cause of eutrophication and non-point source pollution is the main source of TP in the backwater area in the Pengxi.