长江三峡库区蓄水后水质状况分析

2003年5—6月和10月对三峡库区蓄水后的水污染状况进行了监测分析.结果显示，蓄水后库区以Ⅲ类水质为主.若考虑粪大肠菌群指标，总体水质以Ⅳ类和劣Ⅴ类为主.三峡库区重金属含量符合《渔业水质标准》(GB11607-89)与《地表水环境质量标准》(GB3838-2002)Ⅰ类标准的要求.但各监测断面Pb含量较高，两期采样Hg含量均超过了《地表水环境质量标准》(GB3838-2002)Ⅲ类标准.三峡库区共检出19种挥发性有机污染物，其中国家《地表水环境质量标准》(GB3838-2002)控制的特定化学物质5种，分别为1,2-二氯乙烷，1,1,2-三氯乙烷，1,4-二氯苯，1,2-二氯苯，六氯丁二烯，但均不超标.挥发性有机污染物以卤代烃为主，苯系物较少.与国内其他水体相比，三峡库区水体受到挥发性有机物的污染较轻. 

Status of Water Quality in the Three Gorges after the Water Storage Period

The water pollution status was monitored and analyzed for the Three Gorges reservoir area after the second stage of water storage in May, June and October, 2003. The results showed that the overall water quality in the reservoir area was mainly at Grade Ⅲ of Water Quality Standard for Surface Water Environment (GB3838-2002). With consideration of the index of fecal coliform bacteria, the water quality belonged to Grade Ⅳ or sub-Ⅴ as a whole. The concentration of the heavymetals met the water quality standard of Grade Ⅰ of Water Quality Standard forFisheries (GB11607-89) and GB3838-2002 except that the lead concentration was high at all the monitoring sections and the mercury exceeded Grade Ⅲ of GB3838-2002 for 2 times of sampling. 19 kinds of volatile organic compounds (VOCs) were detected within which the 1,2-dichloroethane, 1,1,2-trichloroethane, 1,4-dichlorobenzene, 1,2-dichlorobenzene and hexachlorobutadiene belonged to the controlledstandard items of Environmental Quality Standard for Surface Water (GB3838-2002). The detected value of these chemicals did not exceed the standard, and the VOCs were mainly halogenated hydrocarbons with less benzene series compounds. The VOCs pollution was slightly compared with other domestic rivers during the period.