青海典型内陆河流域地表水化学组成及其重金属分布特征

Chemical composition and heavy metal distribution in surface water of typical inland rivers in Qinghai

为了解青海典型内陆河流地表水化学组成及其重金属分布特征,于2015年7—8月对青海巴音河、格尔木河和小柴旦湖流域地表水进行采集,分析了水体主离子、12种重金属浓度等水化学组成,并对水体质量进行了评估。结果表明:研究区河流、湖泊地表水化学组成分别主要受岩石风化及蒸发-结晶作用控制;不同水体重金属浓度分布存在明显差异,多数重金属表现为湖泊高、河流低,而这与湖泊水化学及水体蒸发导致的重金属元素浓缩富集及结晶析出有关。主成分分析表明,水体重金属主要来源于岩石风化,受人类活动影响较小。研究区河水重金属基本符合《地表水环境质量标准》(GB 3838—2002)Ⅰ类水质标准。

To reveal the hydrochemical composition and the distribution of heavy metals in the surface water of typical inland rivers in Qinghai, water samples were collected from the Bayin River, Golmud River and Xiao Qaidam Lake during July-August 2015. The concentrations ofmajor ions and twelve heavy metal elements were analyzed, and the water quality was assessed. The results showed that the chemical composition of surface water in rivers and lakes were primarily dominated by the rock weathering and evaporation crystalization processes, respectively. The concentrations of most heavy metals in lakes were higher than those in rivers, due to the enrichment and crystallization of heavy metals caused by lake water chemistry and evaporation. Principal component analyses （PCA） showed that the heavy metals mainly came from rock weathering and were less affected by human activities. The concentrations of heavy metals in river waters met grade I water quality according to the standard of Surface Water Environmental Quality Standard of China （GB 3838-2002）.