新疆和田河流域绿洲区浅层地下水水化学特征及成因分析

Hydrochemical characteristics and formation reasons of shallow groundwater in oasis area of Hotan River Basin,Xinjiang

以和田河流域绿洲区2014年44组浅层地下水样的化学数据为基础,运用描述性统计分析法、Piper三线图、Gibbs图和离子比值法对该区浅层地下水水化学特征进行了分析研究。结果表明,研究区地下水呈中性-偏碱性,大部分为硬度较高的微咸水,且处于氧化状态下。常见阳离子的含量差别较大,由大到小依次为Na^+>Ca^(2+)>Mg^(2+)>K^+;常见阴离子的含量差别不大,由大到小依次为HCO_3^->Cl^->SO_4^(2-)。沿地下水流程从强径流区到弱径流区,离子的含量越来越多,TDS逐渐升高,水化学类型从混合型转变为以Cl-Na型和Cl·HCO_3-Na·Ca型为主。影响研究区地下水化学成分形成和变化的因素主要有蒸发浓缩作用、溶滤作用、阳离子交替吸附作用及人类活动。

Based on 44 sets of groundwater hydrochemical data from the oasis area of Hotan river basin in 2014,the descriptive statistical analysis,Gibbs diagram,Piper diagram and ion ratio method were applied to study the hydrochemical characteristics of shallow groundwater. The results showed that the groundwater in the study area was neutral-alkaline,most of which was brackish water with high hardness and was in oxidation state. The difference among the content of major cations was significant,which in turn were Na＋,Ca（2＋）,Mg（2＋） and K＋. The difference among the content of main anions was not significant,which in turn were HCO3-,Cl- and SO4（2-）. Along the path of groundwater runoff,from the strong runoff area to the weak runoff area,the content of ions and TDS in groundwater increased gradually and the hydrochemical type changed from mixed type to Cl-Na type and Cl·HCO3-Na·Ca type. The changes of chemical composition in groundwater were influenced by evaporation concentration,cation exchange and adsorption,dissolution and human activities.