敦煌绿洲地下水微量元素分布特征及其成因

The characteristics of groundwater trace elements and its controlling factors in Dunhuang Oasis

采用多元统计和水文地球化学分析对中国西北地区敦煌绿洲地下水微量元素分布特征及其成因进行了研究。结果表明:地下水中大多数微量元素含量较低,水质总体良好。地下水微量元素具有明显的地带分布规律,从山前洪积扇扇顶补给地带,到中下游细土平原径流排泄区,多数金属元素含量增加,部分在中游出现极大值。蒸发浓缩作用和水岩相互作用控制了研究区地下水中Sr、V、Cu、Zn、Ni和Cr等多种金属元素的溶解迁移;工农业生产对Be和Sc有明显的影响;Pb的分布体现了降水的元素输入特征;地下水中的氧化还原环境一定程度上控制了地下水中的Ba。

Multivariate statistical methods and hydrogeochemical analysis were applied to study the distribution characteristics and its controlling factors of groundwater trace elements in Dunhuang oasis,Northwest China.The results showed that most of the trace elements were in low concentrations in groundwater,the groundwater quality is generally good. From the recharge zone of the top of the alluvial fan,to the runoff and drainage area of the fine soil plain in the middle and lower reaches,the content of most metal elements increased,and some of them appeared maximum values in the middle reaches. Sr,V,Cu,Zn,Ni and Cr were mainly derived from evaporation and weathering effects of the aquifer. While an anthropogenic source including agriculture pollution and industry were identified for Sc and Be. Meanwhile,the distribution of Pb reflects the input of atmospheric deposition,and the oxidizing/reducing conditions within the groundwater in some extent controlled the distribution of Ba.