化隆—循化盆地不同类型含水层组高氟地下水的分布及形成过程

天然成因的高氟地下水是世界范围内备受关注的环境问题和饮用水安全问题。前人对高氟地下水的形成过程已开展了大量研究,但是对于高原盆地复杂水文地质条件下不同类型含水层组(第四系松散层含水层、基岩裂隙或岩溶含水层以及新生代古近纪以来的碎屑岩含水层)高氟地下水的分布和形成过程尚不明确。本文以化隆—循化盆地为研究区,通过采集、测试研究区内的各类地下水样品,分析研究区内不同类型含水层中地下水的化学特征及同位素特征。结果表明,高氟地下水(1.007.73 mg/L)主要分布在沿黄河的河谷区域和巴燕低山丘陵区域的泉水和潜水中以及深部的承压水中,在垂向上高氟地下水无明显分布规律。接受黄河水入渗补给的河谷潜水中氟离子浓度较低,补给黄河的河谷潜水中氟离子浓度较高。贫钙富钠的弱碱性苏打型水有利于地下水中氟的富集。泉水和潜水中氟主要来源于萤石的溶解,而承压水中氟除了来源于萤石外,还来源于其他含氟矿物。对于潜水和第四系松散层泉水,蒸发浓缩作用促进了地下水中氟的富集。另外,阴离子竞争吸附作用、阳离子交换吸附作用是泉水(第四系松散层泉水和基岩裂隙泉水)和潜水中氟元素富集的主要原因,而承压水中氟离子浓度受竞争吸附作用影响较大,阳离子交换吸附作用影响较小。研究成果可为化隆—循化盆地低氟地下水的勘查和开发提供科学依据。     

Hydrogeochemical characteristics of central Jianghan Plain, China

The central Jianghan Plain is the semi-closed basin in the middle reaches of Yangtze River. A total of 78 water samples targeting groundwater were collected from 75 sites in this study site, the area between Yangtze River and Han River, including rivers and lakes for temperature, pH, electrical conductivity (EC), total dissolved solids (TDS) and ion composition measurements. Correlation matrix was used to assess the geochemical and anthropogenic processes. The most confined groundwater was grouped into HCO₃–Ca–Mg, while phreatic groundwater and surface water had a more diversified hydrochemistry. The spatial variation in overall water quality as well as comparison with WHO (World Health Organization) standards for drinking water is illustrated. Mn, As and NO₃ ^? concentrations were found to exceed the allowable limits for drinking water of WHO guidelines, and they also show remarkable spatial variations. Abnormally high nitrate concentration, up to 150–190 mg/l, was found only in phreatic groundwater, which suggested that the nitrate pollution might be caused by agricultural activities. The present study may be helpful in further studies concerning water quality issues in this area where groundwater is a vital source for drinking and other activities.     

Variation of groundwater hydrochemical characteristics in the plain area of the Tarim Basin,Xinjiang Region,China

Groundwater hydrochemistry could reveal the interaction mechanism between groundwater and the environment, which provides a scientific basis for environmental resources management. In this study, Shukaliefu’s classification method and Piper diagram were adopted to determine the hydrochemical types of groundwater in the Tarim Basin of Xinjiang, China. The method of “one^-vote veto” was applied to evaluate the quality of groundwater. Phreeqc software was used to calculate the saturation indices of calcite and fluorite in groundwater. By comparing groundwater quality data of 2003 and 2011, we characterized the variations in hydrochemical types and water quality types, salinization of groundwater and fluoride geochemistry of the plain area of the Tarim Basin. Results show that the primary anion in phreatic water in the plain area of the Tarim Basin changed from HCO₃ ^? to SO₄ ^2? or Cl^?. On the contrary, the primary anion in confined water changed from SO₄ ^2? or Cl^? to HCO₃ ^?. In 2003, 63.1 % of the sampling points in the study area exceeded the Class III water quality standard of China. In 2011, the proportion increased to 82.5 %. In addition, severe groundwater salinization was found at 19.7 % of the sampling points. Some of the deep groundwater samples were salinized as well. In the Aksu area at the north-west part of the Tarim Basin, F^? concentration exceeding the standard limit (1 mg/L) was found to be 55.0 % of the groundwater samples tested. Based on these findings, it is concluded that the phreatic water in the study area was severely influenced by the industrial wastewater and domestic sewage related to human activities, while the confined water was less affected. The general quality of groundwater was in an aggravation trend, and the groundwater salinization was in a severe condition in this area. The Ca²⁺–Na⁺ ionic exchange, the unsaturated fluorite and oversaturated calcite in the aquifer of the Aksu area are proposed to cause F^? enrichment in groundwater of this area.     

鄂尔多斯盆地南部马莲河流域地下水中锶富集特征及成因分析

马莲河流域地处鄂尔多斯盆地南部黄土高原区,按储水介质和埋藏条件可将地下水分为黄土潜水、基岩潜水和基岩承压水三类,利用2015—2018年流域的295组地下水水化学数据,分析了地下水中锶(Sr²⁺)的质量浓度水平、垂向分布及沿流向分布的特征,并采用因子相关性研究地下水中Sr²⁺的来源和富集成因。结果表明:马莲河流域地下水富锶现象显著,黄土潜水、基岩潜水和基岩承压水中锶的平均质量浓度分别为1.14 mg/l、1.39 mg/l和5.24 mg/l;地下水中锶富集成因主要是含锶矿物天然状态下的水-岩作用,黄土潜水、基岩潜水和基岩承压水三类地下水中Sr²⁺的主要来源分别为碳酸盐岩与铝硅酸盐岩、碳酸盐岩与硫酸盐和碳酸盐矿物的溶滤作用;地下水中Sr²⁺的质量浓度沿流向呈逐渐增大的趋势,在不同区域中随深度变化的趋势不一致。     

冲洪积扇含水层地下水可开采量数值模拟——以文峪河冲洪积扇为例

依据钻孔岩性,水文地质资料,将文峪河冲洪积扇平原分为上游单一潜水区和中下游承压水区,中下游垂向划分为上部弱水含水层和下部较强承压水含水层,对上游潜水和中下游承压水用二维侧向流数学模型,对中下游弱潜水用一维垂向流数学模型,在计算了现状开采条件下的水资源基础上,进一步计算出,在扇上游集中采水时,按工业开采和农业开采,以地下水多年总补排均衡,水位长期稳定的约束条件地下水可开采量。     

Groundwater solute chemistry,hydrogeochemical processes and fluoride contamination in phreatic aquifer of Odisha,India

The work investigates the major solute chemistry of groundwater and fluoride enrichment(F~-) in the shallow phreatic aquifer of Odisha.The study also interprets the hydrogeochemical processes of solute acquisition and the genetic behavior of groundwater F~-contamination.A total of 1105 groundwater samples collected from across the state from different hydro-geomorphic settings have been analyzed for the major solutes and F~-content.Groundwater is alkaline in nature(range of pH: 6.6–8.7; ave.: 7.9) predominated by moderately hard to very hard types.Average cation and anion chemistry stand in the orders of Ca~(2+) Na~+ Mg~(2+) K~+and HCO_3~- Cl~- SO_4~(2-) CO_3~(2-)respectively.The average mineralization is low(319 mg/L).The primary water types are Ca-Mg-HCO_3 and Ca-Mg-Cl~-HCO_3, followed by Na-Cl, Ca-Mg-Cl, and Na-Ca-Mg-HCO_3~-Cl.Silicate-halite dissolution and reverse ion exchange are the significant processes of solute acquisition.Both the geogenic as well as the anthropogenic sources contribute to the groundwater fluoride contamination,etc.The ratio of Na~+/Ca~(2+) 1.0 comprises Na-HCO_3(Cl) water types with F~- 1.0 mg/L(range 1.0–3.5 mg/L)where the F~-bears geogenic source.Positive relations exist between F~-and pH, Na~+, TDS, and HCO_3~-.It also reflects a perfect Na-TDS correlation(0.85).The ratio of Na~+/Ca~(2+) 1.0 segregates the sample population(F~- range: 1.0–4.0 mg/L) with the F derived from anthropogenic sources.Such water types include Ca-Mg-HCO_3(Cl) varieties which are recently recharged meteoritic water types.The F~-levels exhibit poor and negative correlations with the solutes in groundwater.The Na-TDS relation remains poor(0.12).In contrast, the TDS levels show strong correlations with Ca~(2+)(0.91), Mg~(2+)(0.80) and even Cl~-(0.91).The majority of the monitoring points with the anthropogenic sources of groundwater F~-are clustered in the Hirakud Canal Command area in the western parts of the state, indicating the role of irrigation return flow in the F~-contamination.     

The origin of groundwater arsenic and fluorine in a volcanic sedimentary basin in central Mexico: a hydrochemistry hypothesis

A groundwater sampling campaign was carried out in the summer of 2013 in a low-temperature geothermal system located in Juventino Rosas (JR) municipality, Guanajuato State, Mexico. This groundwater presents high concentrations of As and F^? and high Rn counts, mainly in wells with relatively higher temperature. The chemistry of major elements was interpreted with different methods, like Piper and D’Amore diagrams. These diagrams allowed for classification of four groundwater types located in three hydrogeological environments. The aquifers are hosted mainly in alluvial-lacustrine sediments and volcanic rocks in interaction with fault and fracture systems. The subsidence, faults and fractures observed in the study area can act as preferential channels for recharge and also for the transport of deep fluids to the surface, especially in the basin plain. The formation of a piezometric dome and the observed hydrochemical behavior of groundwater suggest a possible origin of the As and F^?. Geochemical processes occurring during water–rock interaction are related to high concentrations of As and F^?. High temperatures and alteration processes (like rock weathering) induce dissolution of As and F^?-bearing minerals, increasing the content of these elements in groundwater.     

内蒙古托克托县潜水与承压水中氟化物的空间分布特征及形成机理

氟是维持人体健康所必需的微量元素,过多或过少的摄入都会造成相应的健康问题。本研究从氟的来源、迁移和富集等角度,揭示了内蒙古呼和浩特市托克托县高氟地下水的空间分布规律及其在潜水和承压水中富集的原因。对研究区60个水样(30个潜水和30个承压水)进行了统计分析、水化学特征研究、聚类分析以及相关性分析。结果表明：潜水中F^- 浓度为0.40~7.20(2.30±1.80) mg/L,承压水中F^- 浓度为0.29~12.70(1.67±2.48) mg/L;地下水中F-浓度与HCO^-₃、Na⁺、溶解性总固体(TDS)和电导率(EC)呈正相关,与Ca²⁺呈一定的负相关关系。高氟水的水化学类型主要为HCO₃·Cl-Na型。受地下水流场的控制,高氟潜水(>5 mg/L)主要分布在地下水的排泄区;承压水中F^- 的富集主要受含水层岩性的影响,氟高浓度(>1.5 mg/L)分布区主要集中在研究区南部的湖积台地区域。     

Hydrogeochemical processes and contaminants enrichment with special emphasis on fluoride in groundwater of Birbhum district,West Bengal,India

The hydrogeochemistry of groundwater in rural parts of Birbhum district, West Bengal, India, has been studied to understand the contaminants and prime processes involved in their enrichment with a focus on F^? concentration. The lithological units consist of Quaternary alluviums with underlying Rajmahal basaltic rocks of Middle Jurassic age. Groundwater occurs in the alluviums, weathered residuum and fracture zone of Rajmahal rocks. Studies show elevated concentration of Cl^?, SiO₂, Fe and F^?; excess Cl^? is attributed to anthropogenic inputs, SiO₂ is ascribed to high degree of weathering of silica rich host rocks, and high Fe is due to the interaction of water with Fe-rich sediments under reducing condition. The F^? concentration is found high (>1.20 mg/L) mainly in water from Rajmahal rocks revealing a lithological control on F^? enrichment. The weathering of silicates and ion exchange are the leading controlling processes for major ions in groundwater. The F^? enrichment is due to the dissolution of F^?-bearing minerals and perhaps also through anion exchange (OH^? for F^?) on clay minerals at high alkaline conditions; precipitation of CaCO₃ favours CaF₂ dissolution leading to elevated F^? concentration. CaHCO₃, the dominant water type, contains low F^? while NaHCO₃ and NaCl types exhibit high F^? concentrations. Among the three spatial associations, Cluster-1 and Cluster-2 are CaHCO₃ type; Cluster-3 shows NaHCO₃ and NaCl waters with low Ca²⁺ and Mg²⁺ and high Na⁺ contents. Cluster-1 and Cluster-2 waters are, in general, drinkable barring the elevated Fe content, while Cluster-3 water is unsafe for drinking due to the high F^? concentration.     

Groundwater circulation and hydrogeochemical evolution in Nomhon of Qaidam Basin,northwest China

In this study, analysis of hydrogeological conditions, as well as hydrochemistry and isotopic tools were used to get an insight into the processes controlling mineralization, recharge conditions, and flow pattern of groundwater in a typical arid alluvial-lacustrine plain in Qaidam Basin, northwest China. Analysis of the dissolved constituents reveals that groundwater evolves from fresh water (TDS =300–1000 mg/l) to saline water (TDS ≥5000 mg/l) along the flow paths, with the water type transiting from HCO ₃?Cl–Na ?Mg to HCO ₃?Cl–Na, and eventually to Cl–Na. Groundwater chemical evolution is mainly controlled by water–rock interaction and the evaporation–crystallization process. Deuterium and oxygen-18 isotopes in groundwater samples indicate that the recharge of groundwater is happened by meteoric water and glacier melt-water in the Kunlun Mountains, and in three different recharge conditions. Groundwater ages, estimated by the radiogenic (³H and ¹⁴C) isotope data, range from present to Holocene (～28 ka). Based on groundwater residence time, hydrogeochemical characteristics, field investigation, and geological structure distribution, a conceptual groundwater flow pattern affected by uplift structure is proposed, indicating that shallow phreatic water is blocked by the uplift structure and the flow direction is turned to the northwest, while high pressure artesian water is formed in the confined aquifers at the axis of the uplift structure.     

Isotopic characteristics of precipitation, surface and ground waters in the Yinchuan plain, Northwest China

The isotopic characteristics of hydrogen and oxygen of various water bodies in the Yinchuan plain were investigated. A total of 131 water samples were collected and another 99 water samples collected by other scholars and the International Atomic Energy Agency were referred to in the study. The stable isotopic compositions of precipitation and lake waters are influenced by dry climate and strong evaporation of the area, and the slope of local meteoric water line and lake water line are smaller than that of global meteoric water line. The isotopic compositions of the Yellow River water are significantly lower than the weighted averages of local atmospheric precipitation and are controlled by the runoff of upstream areas. The isotopes of phreatic water suggest that the single phreatic water is predominantly recharged by the bedrock fissure water of Helan Mountain, while the phreatic water in multilayer structure area is recharged by multiple sources. The confined waters in the area may be recharged under cooler climate conditions than the present, which makes the heavy isotopes depleted. The ³H contents of various water bodies are in the following order: the Yellow River water > multilayer phreatic water > single phreatic water > lake water > drainage ditch water > upper confined water > lower confined water. This is in accordance with the recharge, discharge and circulation conditions of the specific water bodies. The isotope compositions of waters in the Yinchuan plain are mainly affected by external water recharge rather than local precipitation. This study is meaningful and helpful in understanding the groundwater flow systems and water cycle in the area.     

扬-泰-靖地区地下水系统水力联系与硫酸盐污染特征

本文对长江三角洲扬-泰-靖地区第四系松散层地下水中环境同位素(D、18O、34S)的分布特征进行了分析,旨在揭示大气降水、长江水、潜水及承压水之间的水力联系,辨别地下水中硫酸盐的来源及其污染状况。研究结果表明潜水含水层接受大气降水及长江水的补给,硫酸盐主要为农业污染来源或与海源硫酸盐的混合。承压含水层主要接受大气降水的补给,与潜水含水层及长江之间的水力联系较差,硫酸盐来源不同。在研究区顶部和沿江地段的浅层孔隙承压水中,硫酸盐来源于硫化物的氧化;在东部的深层孔隙承压水中,硫酸盐主要来源于硫酸盐岩的溶解或海源硫酸盐的滞留,基本未受到潜水或地表水中硫酸盐的污染。     

白杨水源地潜水水质的Monte-Carlo随机模拟

对白杨水源地的地质和水文地质条件进行简要论述,在此基础上建立了二维潜水地下水水流和水质的数学模型。根据渭河水位、水质、降水量等随机变量的特征,选取Ｍｏｎｔｅ－Ｃａｒｌｏ随机模拟方法对水源地潜水的水流和氯离子浓度进行了评价和预测,求出了潜水水位和氯离子浓度的均值及方差,并对氯离子浓度超过１００ｍｇ／Ｌ的概率给出了定量预测,得出了水源地投产后总输水管道中水的氯离子浓度与渭河水中氯离子浓度密切相关等结论。     

A study on the status of fluoride ion in groundwater of coastal hard rock aquifers of south India

India has an increasing incidence of fluorosis, dental and skeletal, with nearly about 62 million people at risk. High fluoride groundwaters are present especially in the hard rock areas of the country. This paper analyzes the most extensive database on fluoride and other chemical constituent distribution in the coastal hard rock aquifers of Thoothukudi district. A total of 135 samples were collected and analyzed for major cations and anions to assess the geochemical process. The fluoride concentration in drinking waters varied from BDL to 3.2 mg?l^?1 in the study area. Majority of the samples do not comply with WHO standards for most of the water quality parameters. The saturation index of fluorite saturation index was used to correlate with F^? to identify their relationship to increase of fluoride levels. The correlation between the F^? concentration and the water type was also attempted. Spatial distribution of fluoride in groundwater was studied to understand the influencing factors. The relationship of F^? with HCO^? _3, Na⁺ and pH concentrations were studied and found that HCO^? ₃, has good correlation with F^? than the other parameters.     

长江漫滩抽水试验与水文地质参数计算

长江漫滩地区第四系是一个巨厚的复杂含水体,地下水丰富,对深大基坑施工影响极大。南京梅子洲过江通道连接线及青奥轴线地下交通系统工程位于长江下游漫滩,基坑最大开挖深度为27.5 m。为满足基坑降水设计及施工要求,勘察时选择有代表性的地段布置了3组抽水试验井,对潜水含水层及承压水含水层进行抽水试验,根据试验井类型和边界条件,选用潜水完整井稳定流、承压水完整井稳定流及非稳定流、承压水非完整井稳定流及非稳定流等多种地下水计算模型进行参数计算并综合分析,为设计提供水文地质参数,并实地验证了参数的合理性。     

江苏沿淮地区淮河水与地下水补排关系研究

从淮河江苏段与地下水含水层关系出发,认为淮河河床切割了地下水承压含水层。地下水的水动力特征表明地下水接受了淮河水的补给。从水质研究的角度印证了地表水与地下水的补排关系。将淮河水与潜水、微承压、承压水之间进行聚类分析,印证了微承压、承压水与淮河水同源。     

Geochemical processes controlling the elevated fluoride concentrations in groundwaters of the Taiyuan Basin,Northern China

High fluoride groundwater with F⁻ concentration up to 6.20 mg/L occurs in Taiyuan basin, northern China. The high fluoride groundwater zones are mainly located in the discharge areas, especially in places where shallow groundwater occurs (the groundwater depth is less than 4 m). Regional hydrogeochemical investigation indicates that processes including hydrolysis of silicate minerals, cation exchange, and evaporation should be responsible for the increase in average contents of major ions in groundwater from the recharge areas to the discharge areas. The concentration of F⁻ in groundwater is positively correlated with that of HCO₃⁻ and Na⁺, indicating that groundwater with high HCO₃⁻ and Na⁺ contents help dissolve some fluoride-rich minerals. The water samples with high F⁻ concentration generally have relatively higher pH value, implying that alkaline environment favors the replacement of exchangeable F⁻ in fluoride-rich minerals by OH⁻ in groundwater. In addition, the mixing of karst water along the western mountain front and the evaporation may also be important factors for the occurrence of high fluoride groundwater. The inverse geochemical modeling using PHREEQC supports the results of hydrogeochemical analyses. The modeling results show that in the recharge and flow-through area of the northern Taiyuan basin, interactions between groundwater and fluoride-rich minerals are the major factor for the increase of F⁻ concentration, whereas in the discharge area of the northern basin, the evaporation as well as the mixing of karst water has greater contribution to the fluoride enrichment in groundwater.     

Optimization of water resources management using SWOT analysis: the case of Zakynthos Island, Ionian Sea, Greece

Zakynthos, an island of 408 km² in the Ionian Sea, is completely dependent on its groundwater resources for fulfilling the demands of the water supplies. The use of groundwater resources has become particularly intensive during the last decades because of the intense urbanization, the tourist development and the irrigated land expansion that took place. The main aquifers are developed in limestones (karstic), sandstones of neogene deposits (confined) and alluvial deposits (phreatic). This paper focuses on the assessment of their hydrogeological characteristics and the groundwater quality. For this investigation, groundwater level measurements, drilling data, pumping tests and chemical analyses of groundwater samples were used. The average annual consumption that is abstracted from the aquifer systems, is 4.9 × 10⁶ m³ year⁻¹. The exploitable groundwater reserves were estimated to be 3.3 × 10⁶ m³ year⁻¹. In the last decades, the total abstractions exceed the natural recharge, due to the tourist development; therefore the aquifer systems are not used safely. The results of chemical analyses showed a deterioration of the groundwater quality. According to the analyses the shallow alluvial aquifer and the confined aquifer are polluted by nitrates at concentrations in excess of 25 mg L⁻¹. High sulphate concentrations might be related to the dissolution of gypsum. Seawater intrusion phenomena are recorded in coastal parts of aquifer systems. The increased Cl⁻ concentrations in karstic aquifer indicate signs of overexploitation. Strengths, weaknesses, opportunities and threats (SWOT) analysis was applied in order to evaluate the SWOT of the groundwater resources. Moreover, some recommendations are made to assist the rational management that aim at improving the sustainability of the groundwater resources of Zakynthos Island.     

宁夏灵武面子山山前区地下水中氟的富集及分布规律探讨

研究区东部属低山丘陵区及山前侵蚀堆积阶地,西部为黄河冲、洪积平原区,地下水资源丰富．是灵武矿区的主要水源地,但由于地下水中氟离子含量较高,给地下水的利用带来了影响。通过对该区水文地质条件和地下水中氟的水文地球化学特征的研究,认为研究区地下水中氟的含量与水化学类型关系不明显,与PH值及钠／钙值呈正相关关系。初步探讨了影响地下水中氟含量的富集因素及分布规律,研究发现：区内潜水含水层氟含量变化大,常发生突变;承压水含水层则多呈渐变形式;地下水中氟含量的高低主要与补给源中氟含量的高低有关．     

Groundwater quality of Yemen volcanic terrain and their geological and geochemical controls

One hundred thirty boreholes of volcanic aquifers in rural Yemen Highland Groundwaters (YHGs) were chemically investigated to assess the suitability of water for drinking. Focus is to identify inorganic constituents of significant risk to health that occur in groundwaters of this area. Results showed that a number of boreholes contain, apart from fluoride, levels of nitrate, some heavy metals, total dissolved solids, and sulfates that could pose a health risk for consumers. The lateral variations of major ions with depth varied within the same aquifer based on the dynamic equilibrium of groundwater and hydrogeological conditions. The main inorganic groundwater contaminant in volcanic YHG is fluoride which is attributed to groundwater lithology and water type. Fluoride appears high in Ca-poor groundwater and where cation exchanges of Ca for Na are dominant. High F concentration in YHG is an extension of East African fluoride-rich groundwater. Majority of tube wells show that Fe concentration exceeds WHO guideline many folds. Much of the iron and manganese in groundwaters are naturally occurring, since the source rocks are enriched in ferromagnesian minerals. NO ₃ ^? and Cl^? concentrations that have been detected in some wells may indicate sewage and/or agricultural runoff. Elevated concentration of chemical constituents in groundwater is a sign of groundwater degradation.