长江南京段水污染现状及限排总量

通过长江南京段18个水功能区水质的5 a变化趋势,分析主要污染源及其入江排污量,提出了各水功能区限制排污总量和入江污染物削减建议。结果表明:长江南京段2005—2009年期间,83.3%的水功能区达标率均随时间呈下降趋势,2009年83.3%的水功能区所有的水质监测点均没有达到其水质目标;主要污染源头为通江河道,其COD、NH3-N排放量分别占入江排污总量的65.7%、49.9%;工业、企业排污口的COD、NH3-N排放量分别占入江排污总量的20.9%和25.0%。长江南京段水体COD限制排污总量为6.59万t/a,NH3-N限制排污总量为0.26万t/a;需要削减污染物的水功能区包括5个饮用水水源区、1个保留区和3个渔业、农业、工业用水区;削减任务最重的为饮用水水源区,其COD和NH3-N削减率分别在87.0%～99.0%和17.8%～97.4%之间。

Water pollution and permissible pollution bearing capacity of water function zones in Nanjing reach of Yangtze River

Based on a five-year variation trend of the water quality of 18 water function zones in the Nanjing reach of the Yangtze River,the main pollution sources and the quantity of pollutants discharged into the river were evaluated and analyzed.Suggestions on permissible pollution bearing capacity and pollutant reduction of the water function zones are made.The results of the study show the following: The up-to-standard rates of 83.3% of the water function zones decreased with time during the period from 2005 to 2009.The monitored water quality in 83.3% of the water function zones in 2009 did not reach standards.The main pollution sources were the rivers connecting with the Yangtze River,where the discharge of COD and NH3-N were,respectively,65.7% and 49.9% of the total discharge into the river.The discharge of COD and NH3-N at industrial sewage outlets were,respectively,20.9% and 25.0% of the total discharge into the river.The permissible pollution bearing capacities of COD and NH3-N in the Nanjing reach of the Yangtze River were 6.59×104 tons per year and 0.26×104 tons per year,respectively.Pollutants need to be reduced in the water function zones,including five drinking water source regions,one reserved area,and three fishery,agricultural,and industrial water use areas.The pollutants in the drinking water source regions need to be reduced to as large degree as possible.The reduction rates of COD and NH3-N ranged from 87.0% to 99.0%,and 17.8% to 97.4%,respectively.