中文摘要：

突发性水污染是水资源安全面临的最常见的威胁之一,为做好突发性事故的预防、应急监测及应急处理,最大限度地减少对生态环境的破坏,应用扩散理论和风险理论,研究泄漏点下游一定断面在不同泄漏时间有毒物质超标的风险、一定时间不同断面有毒物质超标的风险及有毒物质沿河宽的浓度分布,并计算得出高风险河段和高风险时间段.研究结果表明,超标风险大体呈抛物线型变化,表现出先增大,后减少的规律,高风险河段和高风险时间段的分析,可提供有益的信息,以避开在这些河段和时间段取水,尽可能降低污染事故的危害程度.

英文摘要：

Sudden water pollution accidents seriously threaten the security of water resources. For effective prevention, emergency monitoring, and emergency treatment of water pollution accidents and decrease of their harms to ecological environment to the greatest extent, a study was performed on the over-standard risks of toxic substances both in a certain cross-section for different leakage time and in different cross-sections for a certain leakage time on the lower reaches of leakage points and the distribution of toxic substance concentration along the width of rivers. The high-risk river reaches and high-risk time periods were obtained by calculation. The result shows that the over-standard risk of toxic substances demonstrates a variation trend approximate to a parabolic curve, i.e. first increasing and then decreasing. The analysis of high-risk river reaches and high-risk time periods makes it possible to avoid such high-risk river reaches and time periods, so that the damage induced by water pollution accidents could be reduced.