内蒙古乌梁素海入湖水质超标风险率分析

以内蒙古乌梁素海入流水体为研究对象,考虑湖泊水质的随机性和灰色不确定性,以灰色概率统计理论为基础,引入灰色-随机风险率方法,通过计算并分析2006年、2007年和2008年入湖断面各水质参数存在的超标风险性,反映不同水质参数的污染强度和污染历时的变化过程。结果表明,入湖水体总氮总磷浓度超标风险率呈现逐年上升的趋势;总氮浓度超过Ⅴ类标准值的上限风险率达96.4%,下限风险率达87.7%;总磷浓度超过Ⅴ类标准值的上限风险率达96.2%,下限风险率达86.9%;BOD5浓度超过Ⅴ类标准值的平均风险率达55%;COD浓度超过Ⅴ类标准值的平均风险率达85%。乌梁素海入湖水体污染程度已十分严重,源头水污染防治已刻不容缓。

Analysis on the Exceeding the Risk Ratio of Mouth Water Quality for Wuliangsuhai Lake in Inner Mongolia

With the development of society and economy it is widely believed that water environmental pollution has seriously affected our daily life.Mouth water body of Wuliangsuhai Lake in Inner Mongolia is taken as the research object in this study.To considering randomness and gray uncertainty of lake water quality based on the theory of grey probability and statistics by introducing grey-stochastic risk method,over standard risk of each water quality into water section is been calculated and analyzed from 2006 to 2008 to reflect the change process of intensity and duration of pollution on different water quality parameters.The results showed that in this research four water quality indicators have exceeded Ⅴ class standard of surface water quality assessment.Under the controlled of class Ⅲ and Ⅴ risk rate of the various water quality almost close to 100% and the gray is almost 0.Exceeding the risk ratio of TN and TP concentrations present the rising trend year by year.The upper limit risk rate value of exceeding class Ⅴ standard on TN concentrations reach 96.4%,and lower limit risk rate value reach 87.7%.The upper limit risk rate value of exceeding class Ⅴ standard on TP concentrations reach 96.2%,and lower limit risk rate value reach 86.9%.Average risk rate value of exceeding class Ⅴ standard on BOD5 concentrations reach 55%.Average risk rate value of exceeding class Ⅴ standard on COD concentrations reach 85%.Inflow water body in Wuliangsuhai Lake is suffering from severe eutrophication,organic matter,salinization,and other complex pollution.So it is high time that we took some measures to control source of water pollution which is an essential problem.