北京市通州区浅层地下水水化学特征时空变化分析

Spatial and temporal variation of the hydrochemical characteristics of shallow groundwater in Tongzhou area,Beijing

为分析通州区线层地下水水化学特性的时空分布特性,在19个监测站位采集了2007—2013年的丰、枯水期的浅层地下水样品进行监测。结果表明:丰水期和枯水期地下水水化学组分差别较小,地下水阴离子中HCO-3占绝对主导地位且含量相对稳定,枯、丰水期的浓度均值分别为423和452mg/L,而SO2-4和Cl-受环境影响浓度变化较大;阳离子则以Na+、Ca2+为主,枯、丰水期的浓度均值分别为82和90mg/L与74和79mg/L,而K+的浓度变异最大。丰水期和枯水期各组分间的相关关系基本一致,2007—2013年研究区内地下水化学类型没有明显的变化,主要为HCO3-Ca·Mg、HCO3-Mg·Ca·Na和HCO3·Cl-Ca·Na·Mg型。各水化学组分的空间分布基本上表现出南部浓度高于北部的,这可能与地下水的流向有关。

The analysis on the hydrochemical characteristics of shallow groundwater is important for local groundwater management. In this study, the spatial and temporal distribution of hydrochemical components in the shallow groundwater of Tongzhou area were described based on the monitoring data of 19 sampling wells during dry and flood seasons from 2007 to 2013. The results showed that：The concentrations of hydrochemical components changed slightly in the dry and flood seasons. The HCO3 takes the largest proportion in the anion group with average value of 423 mg/L in the dry season and 452 mg/L in the flood season respectively,and the content of SO24- and CI- fluctuated relatively more significantly. Na~ and Ca2＋ had the largest proportion in the cation group and the concentration of K＋ changed more dramatically than other cations. The correlation of those hydrochemical components in the dry season was the same as that in the flood season. The piper diagram shows that the types of hydrochemistry of the local groundwater in the study area were HCO3-Ca · Mg, HCO3-Mg ·Ca · Na and HCO3 · CI-Ca · Na · Mg, and stable during 2007 and 2013. The spatial distribution results showed that the concentration values in the south part of the study area were higher than those in the north part,which increased with the direction of the regional groundwater flow.