长江三峡库区干流水体主要污染负荷来源及贡献

Sources and quantities of main water pollution loads released into Three-Gorge Reservoir of the Yangtze River

目前三峡水库枯水期已有11.1%的监测断面水质超标。城区江段岸边水质已出现较为严重的污染带。利用面向环境问题的污染负荷计量方法,对长江三峡库区干流水体主要污染负荷来源及贡献进行了分析。结果表明,富营养化污染负荷2003年总量为2.79万t PO43-当量,其中总磷贡献量最大,占总量的45.8%。其次是总氮和CODCr,分别占37.9%和16.4%。城市生活污水和农业施肥是主要来源,分别占总量的61.0%和26.3%。水生生态毒性污染负荷为7 612.6t 1,4-二氯苯当量。其中挥发酚和汞贡献量分别占78.0%和21.2%。来自城市生活污水占76.52%,重点工业企业的占23.48%。富营养化污染负荷有逐年增加趋势。重点工业企业六价铬和铅,城市污水中挥发酚水生生态毒性污染负荷增加较快。

The water quality and its changes of the Three-Gorge reservoir（TGR） are a hotspot after it begins to store water and generate electricity. About 11.1% of water inspecting sites exceed the required quality standards at present. The pollution belts exist in some shores by the urban zones. The main sources and quantities of water pollution loads（WPLs） released into TGR are analyzed by using the problem-oriented approach used in life cycle assessment. The results show that the eutrophic pollution loads （PLs） is 27 900 t PO4^3- eq, in which CODCr accounts for 16.4%, the total nitrogen and phosphorus for 37.9% and 45.8%, respectively. The municipal sewages （MSs） and agriculture chemical fertilizers are the two biggest contributors, which account for 61.0% and 26.3% respectively. The freshwater aquatic ecotoxicity （FAETs） PLz is 7612.6 t 1, 4-dichlorobenzene eq, of which the contribution rates are 78.0% for volatilization hydroxybenzenes （VHs） and 21.2% for mercury. 76.5% from MSs and 23.5% from main industrial enterprises （MIEs）. The total eutrophic PLs, as well as the FAETs PLs of Cr^6＋ lead from MIEs, and VHs from MSs are increasing.