根据1981—1990年的黄河水质监测资料分析,黄河流域大夏河和洮河以下各主要河流的水质呈不断恶化趋势。耗氧有机物和氮类污染物大范围急剧增长,挥发酚及汞等污染物在多数河段未得到有效控制,并在一些河段迅速升高。黄河干流自刘家峡水库以下,主要污染物质为汞、耗氧有机物及挥发酚、石油类等。近 According to the monitoring data of the Yellow River water quality from 1981 to 1990, the water quality of the major rivers below the Daxia River and the Bahe River in the Yellow River Basin is deteriorating continuously. Oxygen-rich organic pollutants and nitrogen pollutants increased sharply in a wide range. Pollutants such as phenol and mercury were not effectively controlled in most of the river sections and rapidly increased in some river sections. The mainstream of the Yellow River from Liujiaxia reservoir below, the main pollutants for mercury, oxygen-consuming organic matter and volatile phenol, petroleum and so on. near