滨州市浅层地下水化学时空变化及成因分析

Temporal and Spatial Variation and Cause of Shallow Groundwater Chemistry in Binzhou City

随着海平面升高和全球气候变化,沿海城市地下水化学的长期演变规律研究变得尤为重要。通过采集2010~2020年滨州市浅层地下水样(250个),运用数理统计、ArcGIS空间插值、相关性分析、Piper三线图、Gibbs图及离子比等方法系统地分析了近10年来地下水化学时空演变规律及成因,结果表明:(1)研究区水体整体呈弱碱性,以微咸水为主,地下水阳离子以Na^(+)为主,阴离子以Cl^(-)为主;由陆向海,水化学类型由Ca-SO_(4)·HCO_(3)型过渡到Na·Mg-HCO_(3)·SO_(4)、Na·Mg-Cl·HCO_(3)型,近海迅速转化为Na·Mg-Cl及Na-Cl型;(2)水化学组分年际变化表现为:TDS、Na^(+)、Cl^(-)、SO_(4)^(2-)和NO^(-)_(3)在2012~2013年显著升高,2013~2020年波动降低,2013年区域TDS突增主要受海水入侵影响;水化学组分空间分布为:TDS、Na^(+)、K^(+)、Mg^(2+)、Ca^(2+)、Cl^(-)和SO_(4)^(2-)浓度空间变异不大,由陆向海浓度增高,并在博兴县北部沿黄河区域出现极大值,主要受河道补给状况影响;NO^(-)_(3)浓度空间变异较大,10年间在小清河流域浓度显著增高,增幅为15.81 mg/(L·a);(3)由陆向海,水化学控制因素由岩石风化控制型过渡至蒸发浓缩控制型;(4)Ⅰ区Na^(+)、Cl^(-)主要来源于岩盐及钠长石,Ⅱ区Na^(+)来源受到上游生活污水影响,Ⅲ、Ⅳ区部分水体受海水影响较重,Na^(+)、Cl^(-)可能来源于海水,SO_(4)^(2-)、Ca^(2+)则主要来源于石膏。

With the rise sea levels and global climate changes,the long-term evolution of groundwater chemistry study in coastal cities has become particularly important.By collecting 250 shallow groundwater in Binzhou from 2010 to 2020,the temporal and spatial evolution of groundwater chemistry in recent 10 years are systematically analyzed with statistics,ArcGIS spatial interpolation,correlation analysis,Piper diagram,Gibbs figure and ion ratio.The results show that:(1)The water in the study area is generally weakly alkaline and mainly brackish,groundwater cations are mainly Na^(+),and anions are Cl^(-);From land to sea,the hydrochemistry type transited from Ca-SO_(4)·HCO_(3) to Na·Mg-HCO_(3)·SO_(4) and Na·Mg-Cl·HCO_(3)type,and rapidly changed to Na·Mg-Cland Na-Cl type in the offshore area.(2)The interannual variation of hydrochemical components is as follows:TDS,Na^(+),Cl^(-),SO_(4)^(2-)and NO^(-)_(3) increased significantly from 2012 to 2013,and the sudden increase of reginal TDS in 2013 years is mainly affected by seawater intrusion;The spatial distribution of hydrochemical components is as follows:the spatial variation of TDS,Na^(+),K^(+),Mg^(2+),Ca^(2+),Cl^(-)and SO_(4)^(2-)concentration is small,the concentration increases from land to sea,and there is a maximum along the Yellow River in the north of Boxing County,which is mainly affected by the river supply.The spatial variation of NO^(-)_(3) concentration is large,and the concentration increases significantly in Xiaoqing River Basin in the past 10 years,with an increase of 15.81 mg/(L·a).(3)The chemical control factors from land to sea water change from rock weathering control type to evaporation concentration control type.(4)The Na^(+)and Cl^(-)in zoneⅠmainly come from rock salt and albite,the Na^(+)in zoneⅡis mainly affected by upstream domestic sewage,some water bodies in zoneⅢandⅣare seriously affected by seawater,Na^(+)and Cl^(-)may come from seawater,SO_(4)^(2-)and Ca^(2+)mainly come from gypsum.