青海湖流域水化学分析及水质初步评价

The chemical composition and quality evaluation of surface water in Qinghai Lake areas

为了解青海湖流域水化学的组成及水质状况,于2009年冬季采集了青海湖湖水及流域内主要支流河水样品,并分析了水样中的化学组成。结果表明,青海湖水质总体较好,但部分指标如pH、COD已达到水质V级标准。另SO_4^(2-)和Ca^(2+)是青海湖支流水样中最主要的阴阳离子,而湖水中则是Cl^-和Na^+。溶解性有机碳(DOC)和化学需氧量(COD)表现出相似的变化趋势,反映出青海湖流域局部水系的有机物污染比较严重。分析青海湖湖水中Mg^(2+)/Ca^(2+)以及河水中Cl^-/Na^+数据表明青海湖湖水化学组成主要由蒸发和结晶作用产生,河水的化学组成则主要是由于碳酸盐的风化作用生成。

In order to understand the chemical composition and the quality of surface water in Qinghai Lake areas, water samples in river and lake were collected in 2009. In general, the water quality of surface water in Qinghai Lake was pretty good, although pH and COD exceeded the class V of water quality standard. Ca2＋ and SO42- were the main cation and anion of river water samples, while Cl- and Na＋ were the main ionic species of lake water samples. The levels of DOC and COD revealed the serious organic pollution of surface water in Qinghai Lake areas, and some measurement should be taken to improve the water quality in this area. The ions composition of water between river and lake showed remarkable different, which implied that the chemical composition of the lake water was mainly decided by evaporation and crystallization, while the chemical composition of the river water was mainly decided by decomposition of carbonate.