中文摘要：

研究了受到汞严重污染的第二松花江20年来水体净化过程，并对已有的模型进行了检验．利用切断污染源后5次系统监测资料，通过回归分析建立了沉积物和平水期江水汞浓度变化的数学模型．同时，对未来15a水体汞污染趋势进行了预测．结果表明，第二松花江汞污染自然净化取得明显成效；表层沉积物净化速率高于中下层；第二松花江水体自然净化经历两个阶段，在汞污染源切断初期第二松花江汞污染净化速率较快，目前处于净化速率较慢的时期．预测结果显示，未来水体净化速率将更为缓慢．

英文摘要：

The self-purifying process of the Second Songhua River polluted by mercury in the past 20 years is investigated, and the specific present models are tested in this paper. The mathematical models of mercury concentration in the sediments, and river water during the rainless period are established by fitting the data, which were collected for five times after cutting off the pollution sources. Furthermore, mercury pollution in the Second Songhua River in the following 15 years is predicted by using the models. The research results indicate that self-purifying effect of the Second Songhua River polluted by mercury is evident. It is concluded that the self-purifying rate of the surface layer sediment is higher than that in the middle and the bottom layer sediments. The self-purification process acts in different two phases after cutting off the pollution sources. In the beginning, the self-purifying rate of the Second Songhua River is higher, and it becomes lower in the present. It is anticipated that the self-purifying rate in the future would be lower than the present.