四川省出川断面主要污染物通量及来源研究

以2001～2007年实测水文、水质数据为基础,计算了四川省主要出川断面高锰酸盐指数(CODMn)和氨氮(NH3-N)污染负荷通量;利用断面水质目标约束,通过污染负荷历时曲线,分析了区域水环境承载力;在基流分割的基础上,利用水文分割法,识别了区域污染物的主要来源,为从源头上开展三峡水库水环境保护提供数据支撑。分析结果表明,各出川断面干流主要污染物(CODMn、NH3-N)大致在可接受的范围内,2001年以来,出川断面CODMn通量呈降低的趋势,有效的减缓了输入三峡库区的污染物总量,氨氮通量整体稳定。嘉陵江、涪江、渠江流域污染物来源主要为非点源,应重点加强面源的污染防控;长江干流为点面源混合型,简单的削减点源已不能保证高功能水体要求,应加强点源和面源污染的综合防控。

Study on Sectional Outflowing Flux and Source of Pollutants in Sichuan Rivers

In this study, based on the data of hydrology and water quality determined during 2001 - 2007, the sectional fluxes of CODMn and NH3-N flowing out of Sichuan province were calculated. According tO the goal constraint of water quality and duration curves of pollution load, the pollution bearing capability of the local water was analyzed. Based on the base flow separation, hydrograph segmentation was used to identify the main sources of the local pollutants, which provided data support in water environmental protection from headstream for the Three Gorges Reservoir. The results showed that the sectional fluxes of CODMn and NH3-N flowing out of every main river were environmentally acceptable. Since 2001 the outflow flux of CODMn had appeared a reducing tendency, which greatly eased off the total pollutants of the Three Gorges Reservoir area. The outflo~ng flux of NH3-N was stable. In the valleys of Jaling River, Fujiang River and Qujiang River, the main pollutants sourced from point sources, but the non-point sources pollution still needed control; in the valleys of Yangtze River, there were both non-point source and point source pollutions. It was not available to reduce point sources only for getting high quality water, so a comprehensive prevention and controlling of both non-point source and point source pollutions should be strengthened.