包头昆都仑河以西地下水化学特征及成因分析

Hydrochemical Characteristics and Formation Mechanism of Groundwater in the West of Kundulun River in Baotou City

为研究包头市地下水化学特征及离子来源,支撑包头市地下水污染防治和地下水资源合理开发利用,作者在包头市昆都仑河以西区域采集33组地下水样品,综合运用Piper图、Gibbs图、离子比值和多元统计等方法,对包头市地下水化学特征、离子来源和形成机制进行分析。结果表明,研究区地下水为中性-弱碱性水,硬度偏高,溶解性总固体(TDS)介于116~6032 mg/L;阴阳离子分别以SO_(4)^(2-)、HCO_(3)~-和Na~+、Ca^(2+)、Mg^(2+)为主,各离子含量整体表现为潜水高于承压水;地下水水化学类型复杂,阴离子类型以SO_(4)·Cl、HCO_(3)·SO_(4)·Cl和HCO_(3)为主,阳离子类型以Na·Ca·Mg和Ca·Mg为主;地下水化学组分主要受岩石风化溶滤和蒸发浓缩作用的影响,其次为阳离子交替吸附和人类活动,其中TDS、总硬度、Ca^(2+)和Mg^(2+)主要来源于硅酸盐岩和蒸发盐岩的溶解,K^(+)、Cl^(-)和SO_(4)^(2-)主要来源于工矿业活动,HCO_(3)^(-)和NO_(3)^(-)主要来源于碳酸盐岩风化和农业活动,Na^(+)主要来源于岩石风化和工矿业活动。

In order to study the chemical characteristics and ion source of groundwater and support pollution control and prevention,as well as the rational development and utilization of groundwater resources in Baotou City,33 groups of ground⁃water samples were collected from the western area of Kundulun River in Baotou.Piper diagram,Gibbs diagram,ion ratio,and multivariate statistical analysis methods were comprehensively used to analyze the hydrochemical characteristics,ion source and formation mechanism of groundwater.The results showed that the groundwater in the study area was neutral-weak alkaline water,TH was high,and the TDS was between 116~6032 mg/L,the anions and cations were dominated by SO_(4)^(2-),HCO_(3)-and Na^(+),Ca^(2+),Mg^(2+),and the content of ions in phreatic water was more than that in confined water.The hydrochemistry types of groundwater were complex,the types of anions and cations were dominated by SO_(4)·Cl,HCO_(3)·SO_(4)·Cl,HCO_(3) and Na·Ca·Mg,Ca·Mg.The chemical components of groundwater were mainly affected by rock weathering leaching and evapo⁃ration concentration,followed by cation alternating adsorption and human activities,TDS,total hardness,Ca^(2+),Mg^(2+)were mainly derived from the dissolution of silicate rocks and evaporite rocks,K^(+),Cl^(-),SO_(4)^(2-)were mainly derived from the indus⁃trial and mining activities,HCO_(3)^(-),NO_(3)^(-)were mainly derived from the weathering of carbonate rock and agricultural activities,Na+were mainly derived from the rock weathering and industrial and mining activities.