白洋淀湿地地下水系统水化学变化特征及演化模式

在气候变化和人类活动影响下探究区域地下水系统水化学特征及演化规律,对于揭示地下水循环变化、水资源安全与管理、区域生态环境保护等具有重要作用.本研究以白洋淀湿地地区为研究对象,通过对比分析地表水、地下水水化学特征及空间分布规律,研究白洋淀地区地下水系统水化学演化作用及分区模式.研究结果表明白洋淀地区地表水、地下水水化学具...     

山东省东汶河沂南地区地下水水化学特征及形成机理

地下水作为人类重要的水源之一,已经受到了人类活动的明显影响而造成污染,深入研究地下水化学特征及形成机制,对于地下水资源的合理利用具有重要意义.东汶河沂南地区分布着多种类型的含水层,并且农业、养殖业发达,是进行人类活动影响下的地下水水化学形成研究的理想地区.本文综合利用Piper三线图、离子比值法及数理统计(相关性分析、因子分析、聚类分析)等方法,对东汶河沂南地区地下水水化学特征及形成机理进行研究.研究结果表明,本区地下水水化学类型总体以HCO3-Ca、HCO3-Ca·Mg型为主,TDS含量在243～1473 mg/L之间.地下水中HCO-3、SO2-4、Ca2+和Mg2+等离子主要来自于碳酸盐类矿物及硫酸盐类矿物的溶解,而Na+、K+、Cl-、NO-3则主要来自于岩盐溶解和人类活动污染.水岩作用对地下水水化学的影响超过了62.024％;受人类活动影响明显的水样占到了总水样数的13.6％,对地下水水化学的贡献率则达到了20.318％.河谷平原地区受到农业及养殖业等人类活动的污染明显.     

南通海门浅层地下水水化学特征及演化机制

为系统掌握南通海门区浅层地下水水化学现状,在采集区域地下水样本并分析水化学特征的基础上,综合运用描述性统计、相关性分析、Piper三线图、Gibbs模型以及离子比例系数法等分析手段,对南通海门区浅层地下水化学特征及其形成机理进行系统分析。结果表明：HCO3-和Ca2+分别是研究区浅层地下水中占比最大的阴、阳离子;HCO3-Ca和HCO3-Ca·Mg型为该地区主要地下水化学类型;浅层地下水TDS和总硬度的平均质量浓度相对较低,平均值分别为598.00、374.32 mg/L。根据相关性分析,Cl-和Mg2+为影响该区域地下水TDS的特征因子。研究区浅层地下水化学特征主要受到岩石风化作用影响,地下水水质成分主要源自碳酸盐岩和硅酸盐岩等的长期风化溶解。同时,逆向阳离子交换作用也在一定程度上影响着浅层地下水化学的组成。研究结果可为该区地下水开发利用管理提供理论依据和数据支撑。     

和田县(市)地下水水化学基本特征

和田县市位于昆仑山(中段)北麓塔里木盆地南缘,区内地下水水化学从南到北具较显著的水平分带.尤其玉、喀两河冲积平原地下水,由山前弱矿化水向北过渡为低矿化→中等矿化.水化学成份始终以Cl-和Na 为主.垂直方向上除地下水富水性多寡有微量的区别外,其水力特性、水化学特征基本相似,无明显分带性,内地下水中F-含量普遍超标.大量的化验结果表明,受玉龙喀什河河水的净化作用,近河地区地下水F-含量基本符合饮用水标准,远离河流的地区则普遍超标.区内地下水的基本特点是:SO42-含量不高,Cl-和Na 离子占主导地位,而Cl-Na型低矿化水是昆仑山北麓中段地下水水化学特征别于其它地区的独特之处.     

四川成都红层区浅层地下水水化学特征分析——以新津县为例

以新津地区为例,通过统计分析、离子比例系数分析、相关性分析研究了该区浅层地下水类型及水化学特征;结合piper三线图对新津地区49组水化学常量组分的分析,初步对全区不同地貌类型的地下水水样有关水化学参数进行特征分析。新津江层地下水的化学类型、循环规律及形成作用。     

曹妃甸地区地下水水化学形成作用分析

在开展曹妃甸地区环境地质调查评价过程中,利用水化学组分及离子组合方法对曹妃甸地区水化学样品进行分析,结合曹妃甸地区水文地质条件,开展了地下水水化学形成作用研究,认为该区浅层地下水以溶滤地层中的岩盐、碳酸盐矿物和硅酸盐矿物为主,方解石、石膏等贫镁矿物的影响较小,同时,强烈的蒸发浓缩作用对浅层水水化学特征具有重要影响。深层...     

盐池东部白垩系地下水化学特征及演变

以鄂尔多斯白垩系盆地西缘盐池地区白垩系浅层地下水含水层为目的层,在综合分析研究区水文地质条件的基础上,通过野外调查、取样、试验分析,系统整理地下水水化学数据,对该区域白垩系地下水水化学特征进行了分析.结果表明,盐池白垩系地下水化学类型主要为SO42-·Cl-、SO42-型,地下水溶解性总固体总体分布规律是分水岭东部溶解...     

清徐县西边山洪积扇地区地下水水化学特征及水质评价

为探明太原市清徐县西边山洪积扇地区地下水水化学特征及成因,采用统计分析法和模糊数学方法对清徐县西边山洪积扇地区12个地下水水样点的水化学指标进行了分析和综合评价。结果表明:研究区地下水取样点的水化学评价指标中,总硬度和NO3-含量浓度较高,其平均值属于Ⅴ类水极限值,SO42-含量和TDS含量浓度较低,其平均值属于Ⅱ类和Ⅲ类水质;采用模糊数学方法对地下水水质进行综合评价时表明研究区58. 4%的地下水属于Ⅱ类和Ⅲ类水质,可以直接使用,41. 6%的地下水属于Ⅳ类和Ⅴ类水质,需进一步处理后才能使用;对研究区地下水水质成因研究时表明研究区地下水类型主要为HCO3·SO4-Na·Mg·Ca类型,属于碳酸盐富集区,研究区内碳酸盐矿物溶解作用是控制地下水主要离子组分的主要因素。     

焦作太行山前复合含水结构中地下水水化学特征及其形成作用

通过对焦作地区太行山前冲洪积扇地下水主要离子浓度及溶解性总固体的检测,分析水化学分布特征及其成因.结果表明:研究区地下水总体为弱碱性;水化学类型主要为Ca-HCO3、Ca-HCO3·SO4、Ca·Na-HCO3·SO4、Na·Ca-HCO3·SO4;地下水的水化学特征主要受岩石风化和矿物溶解作用控制,且差异不明显,岩盐...     

太原盆地浅层高氟水分布特征及形成机制研究

本文论述了太原盆地浅层高氟水的区域分布规律,即主要分布在太原市以南地区并具有西低东高的分布特征;通过水化学成分统计分析和水化学模拟对高氟水形成机制进行深入研究,取得了一些新的认识:研究区高氟水多为高矿化水,呈现过渡类型水水化学特征,以钠镁、钠钙碱性水居多.氟含量与地下水主要离子成分的配比有一定的对应关系;地下水对含氟矿物的溶解和自身蒸发浓缩是高氟水形成过程中的两种主要水化学作用形式.     

Assessing hydrochemical evolution of groundwater in limestone terrain via principal component analysis

This paper describes the use of multivariate statistical analysis to trace hydrochemical evolution in a limestone terrain at Zagros region, Iran. The study area includes a deep confined aquifer, overlaid by an unconfined aquifer. The method involves the use of principal component analysis (PCA) to assess and evaluate the hydrochemical evolution based on chemical and isotope variables of 12 piezometers drilled in both the unconfined and confined aquifers. First PCA on all variables shows that water–rock interaction under different conditions with respect to the atmospheric CO₂ is the main process responsible for chemical constituents. As a result, combinations of several ratios such as Ca/TDS, SO₄/TDS and Mg/TDS with physico-chemical and isotope variables reveal different hydrochemical evolution trend in the aquifers. Second PCA on the selective samples and variables reveals that displacement of the unconfined samples from dry to wet season follows a refreshing trend towards river samples that is characterized by reducing electrical conductivity and increasing sulphate and tritium contents. However, the refreshing trend cannot be traced in the confined aquifer samples suggesting no recharge from river to the confined aquifer. Third PCA reveals that, chemical composition of water samples in the unconfined aquifer tends to have considerable difference from each other in the end of recharge period. In contrast, the confined aquifer samples have a tendency to show similar chemical composition during recharge period in comparison to end of dry period. This difference is caused by different mechanism of recharge in the unconfined aquifer (through the whole aquifer surface) and the confined aquifer (through the limited recharge area).     

地下含水层水资源赋存条件及其水化学特征—以贵州省安龙县幅为例

以贵州省安龙县1∶50 000水文地质图幅为例,采用含水层探采井的水质、水量监测数据,分析不同含水层水资源赋存特征及其与水化学的相关性。研究结果表明:（1）研究区含水层可分为纯碳酸盐岩管道含水层、非纯碳酸盐岩裂隙含水层、碎屑岩裂隙含水层、松散岩类孔隙含水层4种类型,各含水层中地下水水化学类型均以HCO-Ca?Mg型为主;（2）除非纯碳酸盐岩含水层探采井的降深与水体中Mg2+、HCO-3浓度呈现出显著的负相关性（R2=-0.77/-0.74）外,其余离子浓度与钻井单位涌水量、降深的相关性均不显著,相关系数(R2)均小于0.3;（3）非纯碳酸盐岩含水层和松散岩类含水层的总矿化度（TDS）、总硬度（TH）含量均比纯碳酸盐岩含水层低5 mg?L-1以上,TDS、TH的高值区均集中于纯碳酸盐岩含水层中,而低值区则分布于松散岩类含水层。      

伊犁河支流大西沟河水与地下水转化关系研究

开展河流和地下水转换关系研究对于区域水资源合理开发利用具有重要意义。文章以大西沟河水与地下水转换关系为目标,在分析地下水动力场的基础上,通过水化学类型、溶解性总固体(TDS)、氯离子（Cl-）等水化学以及环境同位素18O、D、T等指标作为示踪剂,分析大西沟河和地下水的转换关系和转化强度。结果表明:研究区河流和地下水化学类型主要为HCO3—Ca,水化学类型空间分布特征相似;TDS和Cl-浓度表现为先增加后下降,但地下水的变化幅度大于河水。通过对大西沟河水和地下水中的水化学和环境同位素指标对比分析,发现研究区河流与地下水之间补给排泄关系具有明显的分段性;从河流出山口到下游地区,河水和地下水之间发生了三次转化关系:在山前倾斜砾质平原区以河水入渗补给地下水为主,补给量占该段潜水径流量的56%;到了细土平原区出现地下水补给河水地段,补给源为承压水越流补给潜水后的混合水体,潜水和承压水补给比例占该段河水径流量的20.4%与58.4%;风成沙漠区河水沿途渗漏补给地下水直至河流断流。本次研究结果为建立研究区水循环演化模式和水资源合理开发利用提供了理论和技术支持。     

塔城盆地地下水氟分布特征及富集机理

塔城盆地位于新疆维吾尔自治区西北部,干旱少雨,蒸发强烈。但相对于新疆其他盆地,塔城盆地地下水水质相对较好,溶解性总固体和F^-含量相对较低。为解译这种差异及盆地内高氟地下水的成因,本文在对盆地地下水样品水化学组分系统分析的基础上,结合多种水文地质调查数据,利用数理统计、离子比及主成分分析等手段,研究高氟水的成因及其分布规律。结果表明:受气候以及地质等因素控制,研究区地下水氟浓度总体较低,高氟水主要分布于扇前洼地及盆地中部的低洼地带;受承压含水层的顶托补给,地下水氟浓度呈现出上高下低的垂向分带特征。研究区地下水径流途径短,水循环快,水岩相互作用时间较短,且山区地下水以深径流形式循环补给平原区深层承压含水层,再顶托补给潜水,避免了强烈的蒸发浓缩作用。山前洪积扇地下水氟富集主要受控于沉积地层中含氟矿物的风化溶解,而岩石风化、蒸发浓缩、阳离子交换、竞争吸附为平原区地下水氟浓度的主要影响因素。     

The groundwater age in the Middle-Upper Devonian aquifer system, Lithuania

³H, δ¹³C and hydrochemical data were used to estimate the corrected groundwater age derived from conventional ¹⁴C age of dissolved inorganic carbon (DIC). The Middle-Upper Devonian aquifer system from the Baltic upland recharge area in eastern Lithuania towards the discharge area on the Baltic Sea coast in the west was considered. The concentration of total dissolved solids (TDS) in groundwater changes from 300 to 24,000  mg/L and increases downgradient towards the coast. The other major constituents have the same trend as the TDS. The hydrochemical facies of groundwater vary from an alkali-earth carbonates facies at the eastern upland area to an alkali-earth carbonate-sulfate and chloride facies at transit and discharge areas. Meteoric water percolating through the Quaternary and Devonian aquifers regulate the initial ¹⁴C activities of groundwater involving two main members of DIC: soil CO₂ with modern ¹⁴C activity uptake and dissolution of ¹⁴C-free aquifer carbonates. Other sources of DIC are less common. ¹⁴C activity of DIC in the groundwater ranged from 60 to 108 pMC at the shallow depths. With an increase of the aquifers depth the dolomitization of aqueous solution and leakage of the “old” groundwater from lower aquifers take place, traced by lower activities (7–30 pMC).     

山东莱芜盆地西北缘古近系半固结含水岩组的特征及其成因

通过岩心、测井、地下水常规离子组分及氢氧同位素样品测试对分布在莱芜盆地西北缘古近系半固结含水岩组物性、水化学特征及地下水补给循环特征进行研究; 结合古新世以来盆地沉积演化史及含水层成岩阶段划分, 分析半固结含水层地下水富集模式。结果表明, 埋深100 m以下的古近系砂砾岩含水层, 长期处在早成岩A期, 呈弱固结-半固结状态, 兼具裂隙与孔隙含水层特性, 且以孔隙为主。与碳酸盐岩含水层水化学特征相似, 水化学类型为HCO3-Ca?Mg型, 现代大气降水作为地下水主要补给来源, 蒸发浓缩作用, 碳酸盐岩、石膏及盐岩溶解参与了地下水化学组分形成。在莱芜盆地北部边界断裂处, 部分断裂所夹断块可作为古近系含水岩组应急找水靶区。     

Hydrochemistry and isotope geochemistry as tools for groundwater hydrodynamic investigation in multilayer aquifers: a case study from Lomellina, Po plain, South-Western Lombardy, Italy

A multicriteria approach in studying hydrodynamics of a multilayer aquifer system has been used in the Lomellina region (Northern Italy). It involves the reconstruction of the hydrogeological framework coupled to the definition of the hydrochemical and isotopic features of the aquifers. A shallow phreatic aquifer, reaching depths of about 60–80 m from the surface, and deeper aquifers containing confined groundwater, were distinguished. Groundwater generally shows mineralisation decreasing with depth; dissolved ions depict calcium-bicarbonate hydrochemical facies and stable isotopes define the recharge mechanisms, the origin of groundwater, and the hydraulic confinement of deep aquifers. The phreatic aquifer is fed by local infiltration and by streams and irrigation channels. Tritium and Carbon-14 groundwater dating indicate long residence times (on the order of thousands of years) for confined aquifers. The confined aquifers show essentially passive hydrodynamic conditions and maintain a higher piezometric level than the phreatic aquifer. This inhibits the possibility of recent water penetrating far below the surface. The hydrogeological setting of the Lomellina region displays features which are common to other sectors of the Po plain. As a consequence, the results of this study, although conducted on a restricted area, are highly illustrative of groundwater hydrodynamics in large sedimentary aquifers.     

Groundwater quality of porous aquifers in Greece: a synoptic review

Greece is dependent on groundwater resources for its water supply. The main aquifers are within carbonate rocks (karstic aquifers) and coarse grained Neogene and Quaternary deposits (porous aquifers). The use of groundwater resources has become particularly intensive in coastal areas during the last decades with the intense urbanization, tourist development and irrigated land expansion. Sources of groundwater pollution are the seawater intrusion due to over-exploitation of coastal aquifers, the fertilizers from agricultural activities and the disposal of untreated wastewater in torrents or in old pumping wells. In the last decades the total abstractions from coastal aquifers exceed the natural recharge; so the aquifer systems are not used safely. Over-exploitation causes a negative water balance, triggering seawater intrusion. Seawater intrusion phenomena are recorded in coastal aquifer systems. Nitrate pollution is the second major source of groundwater degradation in many areas in Greece. The high levels of nitrate are probably the result of over-fertilization and the lack of sewage systems in some urban areas.     

Evolution of the groundwater environment under a long-term exploitation in the coastal area near Zhanjiang, China

Aquifers consisting of unconsolidated sediments in the coastal area near Zhanjiang in southern China are grouped into the shallow, middle-deep and deep aquifer systems. Groundwater exploitation began in the 1950s in this district and has increased from year to year since 1980. Measurements of groundwater levels and monitoring data of groundwater chemistry at some 60 wells since 1981 are examined to analyze the evolution of hydrodynamics and hydrochemistry in the coastal aquifers. The results indicate that groundwater levels in the middle-deep and deep aquifer systems have fallen continuously and the extents of the depression cones in water levels have increased in the past two decades, even though the water levels recovered to some degree during the period of 1997–2001. In 2004, the lowest water levels in the middle-deep and deep aquifer systems were 23.58 and 21.84 m below sea level, respectively. The groundwater has TDS ranging from 40 to 550 mg/L, and is of low pH, commonly varies between 4 and 7. Concentrations of total iron and manganese exceed the concentration limits of the drinking water standards. The hardness is in the range of 10–250 mg/L. Chloride contents of the groundwater range from 10 to 60 mg/L. The chloride and TDS do not show systematically increasing trends. Although the water levels in the exploitation center near the coast are significantly lower than the sea level and the depression cones of water levels in the middle-deep and deep aquifer systems have expanded to the sea, sea water intrusion has not been observed until recently. This phenomenon is quite unique in the coastal area near Zhanjiang.     

Modeling freshening time and hydrochemical evolution of groundwater in coastal aquifers of Shenzhen,China

This work investigated the freshening time and hydrochemical evolution of coastal groundwater in two brackish aquifers in Shenzhen, China. One was the brackish aquifer that resulted from heavy pumping, and the other was the aquifer reclaimed from the coastal sea. Freshening time and hydrochemical evolution of brackish aquifers were quantitatively evaluated using PHREEQC 2.0, a one-dimensional reactive-transport model. Freshening time was shown to mainly depend on pore water velocity, while the chemical composition of groundwater was determined by the cation exchange capacity of the aquifer. It was shown that after heavy pumping ceased, the freshening time for the original coastal aquifer ranged from 20 to over 80 years. While for the coastal reclaimed aquifer, the freshening time was from 85 to 140 years, which depended on the hydraulic conductivity of the fill materials in the reclaimed site. During aquifer freshening, groundwater evolved from Na–Cl type to Ca–Mg–HCO₃ or Na–HCO₃ type. A sensitivity analysis showed that the freshening time was most sensitive to the pore water velocity in the aquifer, while the groundwater chemical composition was most sensitive to the values of cation exchange capacity of the aquifer. As for the dispersivity, it had almost no effect on the freshening time and the chemical composition of groundwater.