宁夏海原盆地地下水水化学特征及其演化规律

结合宁夏海原盆地已有的地质、水文地质资料,基于水化学、同位素数据分析了研究区的水文地球化学特征。总体上当地的地下水化学场从补给区到径流区到排泄区具有明显的分带性,符合干旱区盆地的水质演化规律;地球化学模拟表明当地水岩相互作用从补给区的以溶滤-混合作用为主逐渐演变成排泄区的以溶滤-蒸发为主。水中的溶解性总固体含量升高主要由岩盐和石膏的溶解引起,第三系岩性及径流条件对地下水水质有很大的影响。同位素特征表明西华山-南华山断裂控制着当地地下水的补给,地下水开采对深层地下水水质的影响尚不明显;在有些地区,由于地下水开采加速了地下水径流,水质有变好的趋势。      

开采条件下山东德州深层水资源组成及其与地面沉降的关系

针对德州长期过量开采深层水导致地下水位不断下降、地面沉降等环境地质问题,以深层地下水动态、地面沉降监测及其对应的粘性地层为主要研究对象,应用水文地球化学、地下水动力学和同位素技术方法,初步查明深层水主要形成于末次冰期盛期的大气降水补给;考虑地面沉降条件下,开采资源中20.6%的侧向径流补给和越流补给来自区域径流系统,反映深层地下水具有一定的更新能力;含水层弹性释水占17.5%,其中61.9%来自粘性土的压密释水,这是产生地面沉降的直接原因。     

海原盆地地下水咸化特征和控制因素

地下水是海原盆地唯一的供水水源,近年来部分地区地下水溶解性总固体(TDS)增高,引起了有关部门和水文地质工作者的高度关注。通过分析69组地下水样品的水化学和氢氧稳定同位素数据,对地下水补给来源和咸化的水文地球化学过程进行了研究。结果表明:地下水TDS值198.2~6 436.4 mg/L,沿着地下水流向,咸化程度增加,水化学类型从基岩区的HCO3—Ca·Mg型演化至滞留—排泄区的SO4·Cl—Na·Mg型。地下水补给来源主要为大气降雨和基岩裂隙水侧向径流,补给源—对地下水咸化贡献较小。溶滤作用具空间差异,基岩区和补给区以碳酸盐、硅酸盐风化为主,径流区和滞留—排泄区则为蒸发岩风化,硫酸盐是地下水中阳离子的主要来源。补给水、溶滤和蒸发对第四系地下水TDS的贡献比率分别为4.8%~81.2%、11.9% ~85.9%、1.7%~29.5%,溶滤作用是控制海原盆地地下水咸化的首要因素。当地有关部门应加大对基岩泉水的综合利用,同时注意控制海原县和西安镇等地区地下水开采量,防止地下水进一步咸化。另外,在微咸水分布区可引进地下水去除硫酸盐技术,提高微咸水利用程度。     

江汉平原西部浅层孔隙水水文地球化学特征

为了揭示地下水由江汉平原周缘向中心径流过程中的水质演化和复杂的水文地球化学作用,以江汉平原西部地区为例,通过数理统计、水化学、同位素地球化学、离子比值关系等方法,开展了江汉平原西部边缘地带浅层孔隙地下水的水文地球化学特征研究。结果表明:平原区孔隙水以HCO_3-Ca·Mg型为主,丘岗区(丘陵和岗地)主要是HCO_3-Ca·Mg型,少量为HCO_3·SO_4-Ca·Mg型,还出现了HCO_3·NO_3-Ca·Mg型水,总溶解固体(total dissolved solids,TDS)升高主要是由于碳酸盐岩的溶解;浅层孔隙水均来源于大气降水,蒸发作用对该地区孔隙水的影响较小;方解石、白云石和石膏的溶解主导研究区的水文地球化学过程,也是孔隙水中Ca~(2+)、Mg~(2+)的主要来源,Na~+和K~+的主要来源是阳离子交换吸附。     

水化学—稳定同位素技术在岩溶水文地质研究中的应用

水化学—稳定同位素技术在岩溶水系统分析中得到了广泛的应用,尤其是在指示岩溶水文地球化学过程、识别岩溶水补给循环途径、溶质溯源及岩溶水污染监测防控等方面显示了独特的优势,产生了丰富的成果。本文着重阐述了环境稳定同位素δD、δ18O、87Sr/86Sr的工作原理,及水化学—稳定同位素技术在岩溶水文地质研究中的应用。此外,论文还以娘子关泉域和北京西山岩溶水系统为例,介绍了运用水化学—稳定同位素技术分析岩溶水系统补给的思路和方法,展望了该技术在岩溶水文地质和岩溶生态环境领域中的应用前景。      

宁夏清水河上游浅层地下水咸化作用研究

认识干旱区地下咸水的形成机制对水资源管理和规划具有重要意义。在宁夏清水河平原上游采集52组浅层地下水化学样品和8组易溶盐样品,分析了地下水咸化的水文地球化学作用,利用元素质量平衡法计算了各作用对地下水盐分的贡献比率。结果表明：沿径流方向,地下水咸化程度呈增加趋势。咸化作用主要为岩石风化,并具空间分异,在补给区以碳酸盐风化为主,在强径流区硫酸盐风化占优,在弱径流区硫酸盐和岩盐风化共同提供了68%～93%的盐量。随着地下水TDS增加,蒸发岩贡献比率上升,碳酸盐和硅酸盐贡献比率下降。蒸发岩风化是导致浅层地下水咸化的首要因素。     

深圳沿海带浅层地下水的稳定同位素与地球化学

在深圳沿海带取64件浅层地下水样品,作常规离子水化学和氢氧稳定同位素测试,来识别深圳沿海带海水入侵程度。采用主要离子比值-Cl、Br/Cl比值和piper三线图等水文地球化学方法以及氢氧稳定同位素δD-δ18O、δ18O-Cl结合分析水样数据。分析发现Cl-<300mg/L的样品均来源于降水入渗补给,没有海水混入;300mg/L<885mg />885mg/L的12件样品均有海水混合,系降水(淡水)和海水的混合水。     

华北低山丘陵区潴龙河流域地下水水质特征及成因分析

华北低山丘陵地带是华北平原地下水的主要补给区,土地利用类型多样,研究该区地下水水化学特征并把握其水质影响因素对平原区水质保护具有重要意义。选择位于太行山低山丘陵区的潴龙河流域作为研究区,通过野外调查和采样,利用水文地球化学方法,研究不同土地利用类型地下水水质时空分布特征及形成原因。结果表明,低山丘陵区土地利用类型是影响区域水质空间变化的主要原因;方解石和石膏的溶解是造成地下水以HCO_3—Ca和HCO_3·SO_4—Ca型为主的主要原因;与上游自然条件下地下水对比,受人类活动影响较大的区域如村庄化粪池等点源污染和农田面源污染是造成地下水中Cl~-、NO~-_3以及Ca~(2+)浓度升高的主要原因。由于低山丘陵区含水层渗透性较强,因此必须加强对人类活动引起的点源污染的防控。     

河套灌区西部浅层地下水咸化机制

浅层地下水水位埋深浅、含盐量高,是导致河套灌区土壤次生盐渍化的重要原因.以河套灌区西部地区为研究区,通过对浅层地下水的水化学和氢氧同位素特征分析以及水文地球化学模拟,探讨了灌区浅层地下水的补给来源和主控水-岩作用过程,并定量估算了蒸发作用对浅层地下水含盐量的影响.研究区内浅层地下水为弱碱性咸水,pH为7.23~8.45,总溶解性固体（total dissolved solids,TDS）变化范围为371~7 599 mg/L;随着地下水咸化程度增大,水化学类型由HCO₃-Na·Mg·Ca型向Cl-Na型过渡.引黄灌溉和大气降水是浅层地下水的主要补给来源,径流过程中浅层地下水受蒸发作用和植物蒸腾作用影响,地下水化学组分主要来源于蒸发盐溶解和硅酸盐风化水解,并受强烈的蒸发作用和离子交换作用影响.水文地球化学模拟和主成分分析结果显示,蒸发作用和岩盐溶解作用对区内浅层地下水咸化贡献最大,石膏和白云石等矿物的溶解、硅酸盐的水解、Na-Ca离子交换以及局部地形起伏对地下水咸化过程也有较大贡献.      

水文地球化学方法在煤矿水害研究中的某些应用——以平顶山、肥城矿区研究为例

矿井防治水的理论和工程实践表明，水文地球化学方法是矿井水害预防和治理工作中较为有效的一种方法，以平顶山矿区、肥城矿区为例，阐述了水文地球化学方法在水害研究中的某些应用，在平顶山矿区、环境同位素（氢、氧）和统计分析（聚类分析）技术的研究结果，进一步证实和校正了以往对该区水流系统的概念模型，即局部水流系统和过渡水流系统（或西南部和东北部子系统）的划分仅适于寒武系灰岩含水系统；砂岩含水层在矿区中、北部低山区接受大气降水补给，并有可能补给薄层灰岩含水层。在肥城矿区，地下水示踪试验结果表明，该区的GF9，F7－1、F7－3断层在试验段内具有较强的导水性，奥灰水可通过上述断层并以不同特征的通道和速度继续径流并补给各井下出水点，因而是该区煤矿安全的主要威胁。     

张掖盆地龙首山山前高氟地下水的形成

氟是人体的必须元素之一,饮水中氟元素过量会导致地氟病。高氟地下水的形成机制一直是水文地球化学研究的一个热门话题。利用在张掖盆地开展1∶5万水文地质调查所获得的大量水位、水质资料,运用水化学和氘氧同位素方法,在较高精度水平上探讨了龙首山前高氟地下水的形成机制。研究结果表明,龙首山前地下水中的F-主要来源于龙首山含氟岩石,通过季节性洪水的方式补给到盆地的第四系含水层中,并与盆地上游来源的低氟地下水发生混合,使龙首山前地下水分为三个条带。     

岩溶矿区水文地球化学特征及其水源指示意义

云南毛坪铅锌矿区属于复杂型岩溶裂隙充水大水矿床,亟需查明其充水水源、径流途径以开展地下水防治工程设计与优化。基于水化学、氢氧同位素方法对矿区充水水源进行系统研究与辨识,并对矿区水文地质概念模型作了初步分析。矿区石炭系地下水表现为低水温、低TDS、高NO-3、富集重同位素,而矿区泥盆系地下水由北往南水温、TDS逐渐升高,NO-3浓度降低,微量组分浓度升高,且尤为富集轻同位素。研究结果表明以上组分均对矿区充水水源辨识有直接指示意义:石炭系主要受东侧献鸡一带岩溶洼地区补给,自东往西向矿区径流,并经由断层构造向矿区泥盆系北部补给,同时与泥盆系南部深层水源混合后排泄于矿区疏干漏斗中心。     

Groundwater quality assessment using integrated geochemical methods,multivariate statistical analysis,and geostatistical technique in shallow coastal aquifer of Terengganu,Malaysia

Extensive agricultural, residential, and industrial activities have increased demand for water supplies, which can lead to groundwater quality degradation. The integration of geochemical methods, multivariate statistical analysis, and geostatistical approaches were carried out on 169 groundwater samples to elucidate the regional factors and processes that influencing the geochemical composition of groundwater in coastal shallow aquifer of Terengganu, Malaysia. Hydrochemical modelling revealed that the abundance of Ca and Mg was contributed by carbonate and silicate weathering while higher HCO₃ and Cl were resulted from reverse ion exchange reaction. Therefore, the dominant hydrogeochemical facies of groundwater was Ca-Mg-HCO₃-Cl type. The influence of salinization resulting from seawater mixing to the groundwater was corroborated by Cl/HCO₃ ratio, which affected around 50.9% of the groundwater samples slightly or moderately. Spatial mapping using ordinary kriging found that the threat of sea water intrusion is more prominent in the major river confluence especially around Terengganu and Marang River in the northeast and Dungun and Kemaman River confluence in southeast of study area. Moreover, factor analyses concluded that salinization, anthropogenic activities, reverse ion exchange, weathering processes, agricultural impact, and seasonal variations were the factors that regulate 63% of the major ion chemistry in study area. Finally, these findings showed the importance of understanding the hydrochemical characteristics for effective utilization, aquifer protection, and prediction of changes to minimize the effects of salinization and reduce human pollution such as agriculture and urbanization. It is essential steps in order to safeguard the utilization of groundwater resources for future generations.     

Delineation of groundwater provenance in a coastal aquifer using statistical and isotopic methods,Southeast Tanzania

Rapid population growth and urbanization has placed a high demand on freshwater resources in southeast costal Tanzania. In this paper, we identify the various sources of groundwater and the major factors affecting the groundwater quality by means of multivariate statistical analyses, using chemical tracers and stable isotope signatures. The results from hierarchical cluster analyses show that the groundwater in the study area may be classified into four groups. A factor analysis indicates that groundwater composition is mainly affected by three processes, accounting for 80.6% of the total data variance: seawater intrusion, dilution of groundwater by recharge, and sewage infiltration. The hydrochemical facies of shallow groundwater was mostly of the Na–Ca–Cl type, although other water types were also observed. The deep groundwater samples were slightly to moderately mineralized and they were of the NaHCO₃ type. This water type is induced mainly by dissolution of carbonate minerals and modified by ion exchange reactions. The signal from the stable isotope composition of the groundwater samples corresponded well with the major chemical characteristics. In the shallow groundwater, both high-nitrate and high-chloride concentrations were associated with localized stable isotope enrichments which offset the meteoric isotopic signature. This is inferred to be due to the contamination by influx of sewage, as well as intrusion by seawater. The depleted stable isotope values, which coincides with a chemical signature for the deep aquifer indicates that this deep groundwater is derived from infiltration in the recharge zone followed by slow lateral percolation. This study shows that a conceptual hydrogeochemical interpretation of the results from multivariate statistical analysis (using HCA and FA) on water chemistry, including isotopic data, provides a powerful tool for classifying the sources of groundwater and identifying the significant factors governing the groundwater quality. The derived knowledge generated by this study constitutes a conceptual framework for investigating groundwater characteristics. This is a prerequisite for developing a sound management plan, which is a requirement for ensuring a sustainable exploitation of the deep aquifer water resource in the coastal area of Tanzania.     

Compilation of Groundwater Quality Map and study of hydrogeochemical characteristics of groundwater in Asia

The groundwater quality map is among a series of Asian groundwater environment maps, which has been compiled and is about to be published. The article introduces the central theme and main content of the map, evaluates the method applied for groundwater quality gradation, and discusses hydrogeochemical characteristics of Asian groundwater. The distribution of water quality is investigated through the data collection of selected elements; hydrogeochemical characteristics are demonstrated via the analysis of elements’ allocation in horizontal and vertical zones; whilst the groundwater quality is evaluated by the Analytic Hierarchy Process (AHP).     

Groundwater monitoring in Denmark: characteristics, perspectives and comparison with other countries

More than 99% of water use in Denmark is based on groundwater. Denmark has had a comprehensive national groundwater-monitoring programme since 1988 based on 74 well catchment areas and six small agricultural catchments with more than 1,500 screens at different depths for regular, mostly annual, water quality sampling. In addition, water samples from 10,000 abstraction wells are analysed every 3–5 years. The water is analysed for main components, inorganic trace elements, organic micro pollutants, and pesticides and their metabolites. A unique feature is the 20-year time-series data of inorganic pollutants. Groundwater modelling supports traditional monitoring to improve the conceptual geological understanding and to assess the quantitative status and the interaction between groundwater and surface water. The programme has been continuously adjusted to incorporate new knowledge from research programmes and meet new policy demands, currently the European Union Water Framework Directive, particularly with respect to an increased focus on quantitative aspects and on the groundwater/surface water interaction. The strengths and weaknesses of the Danish programme are assessed and compared with other national groundwater-monitoring programmes. Issues discussed include: strategic considerations for monitoring design, the link between research and monitoring, and adoption of responses to climate changes.     

Factors controlling mechanisms of groundwater salinization and hydrogeochemical processes in the Quaternary aquifer of the Eastern Nile Delta, Egypt

In this study, combining interpretations of conservative dissolved ions and environmental isotopes in water were used to investigate the main factors and mechanisms controlling groundwater salinization and hydrogeochemical processes in the Eastern Nile Delta, Egypt. Hydrogeochemical and isotopic study has been carried out for 61 water samples from the study area. Total dissolved solid (TDS) contents of groundwater are highly variable rising along flowpath from the south (410 mg/L) to the north (14,784 mg/L), implying significant deterioration and salinization of groundwater. Based on TDS and ionic ratios, groundwater samples were classified into three groups. In low-saline groups, water chemistry is greatly influenced by cation exchange, mineral dissolution/precipitation, anthropogenic pollutants and mixing with surface water. Whilst, in high-saline groups, water chemistry is affected by salt-water intrusion, reverse cation exchange and evaporation. The chemical constituents originating from saline water sources, reverse ion exchange and mineral dissolution are successfully differentiated using ionic delta and saturation index approaches. The δ¹⁸O–δ²H relationship plots on a typical evaporation line, suggesting potential evaporation of the recharging water prior to infiltration. Isotope evidence concludes that the groundwater have been considerably formed by mixing between depleted meteoric water recharged under different climatic conditions and recently infiltrating enriched surface water and excess of irrigation water. The δ¹⁸O data in conjunction with chloride concentrations provide firm evidence for impact of dissolution of marine-origin evaporite deposits, during past geologic periods, on groundwater salinity in the northern region. Moreover, the relation between ¹⁴C activities and Cl^? concentration confirms this hypothesis.     

地下水污染调查中水样有机组分分析质量控制

根据《地质矿产实验室测试质量管理规范》的要求,为保证地下水污染调查中样品的准确测定,需采取质量控制方法。文章阐述了地下水样品的前处理和测定过程的质量控制措施,建立了地下水有机组分分析过程的质量控制流程,确保其检测数据达到规范所允许的范围。     

Evaluation of groundwater resources for drinking and agricultural purposes, Abar Al Mashi area, south Al Madinah Al Munawarah City, Saudi Arabia

A hydrogeochemical study was conducted on the groundwater of south Al Madinah Al Munawarah City, Saudi Arabia, to assess the quality of groundwater for drinking and irrigation uses. Groundwater samples have been collected and analyzed for major and some trace constituents from the study area. The nitrate concentration in most groundwater samples of the study area exceeded the safe limits for drinking purposes, whereas the concentrations of phosphate, boron, and trace constituents were below the maximum permissible limit for drinking purposes; Cr in two samples showed high content over the recommended limits of drinking purposes. Uncontrolled abstraction of groundwater in Abar Al Mashi area caused many environmental problems including water resource depletion and contamination. Correlations between chloride and major ions were positive and may be attributed to impact of agricultural activities on groundwater chemistry. Groundwater of the study area was classified into six water types. The chemical water types of groundwater in the study area contain CaHCO₃ in the eastern and southeastern parts and NaCl in western and northwestern parts, reflecting different land use characteristics and pollution sources. Piper diagram showed that almost all the samples fall in one zone, indicating similar chemical signature. Groundwater can be used safely for drinking with special treatments to eliminate the effect of increased concentrations of total dissolved solids, nitrate, and chromium. The groundwater of the study area can be used safely for irrigation on clay soil; however, specific crops should be selected according to their salt tolerance.     

广东硇洲岛地下水化学演化及成因机理

地下水一直是广东硇洲岛唯一的水资源,但近年来许多地区地下水咸化趋势加剧,严峻威胁着岛上居民的用水安全,研究地下水化学演化及成因机理,对预防和减缓水质变咸意义重大。本文结合区域水文地质条件、地形地貌条件及水化学资料分析了整个岛屿地下水水质状况,在此基础上采用Piper三线图研究了水化学特征,并利用PHREEQC软件对水文地球化学演化规律进行模拟研究,结果表明:(1)海水入侵是造成地下水咸化的主要原因,咸化对水质的影响主要表现为Cl-的增加,Ca2+在区分该地区不同水体时反应灵敏,是良好的识别指标之一;(2)海水入侵的过程中,过渡带前缘不存在经受长期古海水演化而成的卤水与地下淡水的混合作用,地下水中Mg2+、Ca2+与Na+之间存在着强烈的离子交换,石膏、白云石及方解石处于不饱和状态;(3)浅层地下水与深层地下水之间无明显的水力联系,属于相对独立的地下水流系统。在全球变暖,海平面上升的总趋势下,海岛地下水开发必须合理规划、严格管理,以防引发大规模海水入侵灾害的发生。