洱海水质评价

本文对洱海流域水环境状况进行了系统全面评价。评价结果表明洱海污染源以面源为主，湖面降水和内源释放次之，工业和城镇生活的污染贡献率相对较低。洱海的主要超标污染物是总磷和汞，其中总磷污染最为严重。洱海从1992～2001年富营养化水平保持在中营养水平，现正处于中营养向富营养湖泊的过渡阶段。洱海在1993～2000年之间，总硬度和总氮上升趋势明显。洱海运行水位对洱海水体总磷的变化影响明显。

Assessment on Erhai Lake water quality

The authors systematically assessed and analyzed the water quality situation of Erhai Lake in this paper.It is found that non-point source is the major type of pollution sources in the lake basin,pollutants with wet precipitation and inner source pollution are secondary,industrial and domestic sources are secondary.The main contaminations are total phosphorus(TP) and mercury(Hg).TP is identified as the most polluted item.The eutrophic level of Erhai Lake from 1992 to 2001 remained at a middle level,and now it is turning to an eutrophicating level.The increasing trend of hardness and TN in the period from 1993 to 2000 was prominent.It is also identified that water level operation of Erhai Lake would obviously affect TP concentration.