高碘地下水成因与分布规律研究

我国是世界上已知面积最大的水源性高碘国家,碘的长期过量摄入对居民健康产生极大威胁。在不同的环境水文地质条件下,高碘地下水成因模式可概括为:埋藏-溶解型、压密-释放型和蒸发-浓缩型。基于对高碘地下水成因机理的认识,我们利用大数据模型预测了全国高碘地下水赋存情况,发现其高风险区(p>0.5)约占国土面积的19.8%,且涵盖了全部已知的高碘地下水分布区。开展地下水系统中有机碘形态定量表征、碘的水文地球化学行为微观机理识别和迁移活化过程定量模拟研究,将深化对高碘地下水成因与分布规律的认识,为供水水质安全和预防水源性高碘甲肿提供重要的科学依据。     

Overview of groundwater sources and water-supply systems,and associated microbial pollution,in Finland,Norway and Iceland

The characteristics of groundwater systems and groundwater contamination in Finland, Norway and Iceland are presented, as they relate to outbreaks of disease. Disparities among the Nordic countries in the approach to providing safe drinking water from groundwater are discussed, and recommendations are given for the future. Groundwater recharge is typically high in autumn or winter months or after snowmelt in the coldest regions. Most inland aquifers are unconfined and therefore vulnerable to pollution, but they are often without much anthropogenic influence and the water quality is good. In coastal zones, previously emplaced marine sediments may confine and protect aquifers to some extent. However, the water quality in these aquifers is highly variable, as the coastal regions are also most influenced by agriculture, sea-water intrusion and urban settlements resulting in challenging conditions for water abstraction and supply. Groundwater is typically extracted from Quaternary deposits for small and medium municipalities, from bedrock for single households, and from surface water for the largest cities, except for Iceland, which relies almost entirely on groundwater for public supply. Managed aquifer recharge, with or without prior water treatment, is widely used in Finland to extend present groundwater resources. Especially at small utilities, groundwater is often supplied without treatment. Despite generally good water quality, microbial contamination has occurred, principally by norovirus and Campylobacter, with larger outbreaks resulting from sewage contamination, cross-connections into drinking water supplies, heavy rainfall events, and ingress of polluted surface water to groundwater.     

Extent and nature of hydrocarbon occurrence in the groundwater of Kuwait

A study, aimed at characterizing the nature of anthropogenic and biogenic hydrocarbon contamination in the groundwater of Kuwait, was carried out using fluorescence spectroscopy and other analytical techniques. The results of these analyses have demonstrated that the groundwater in certain areas of northern Kuwait has been significantly impacted by contamination originating from the oil-contaminated surface soils. The study revealed that a water-soluble fraction (WSF) of the crude oil surface contamination appeared to be slowly leaching into the freshwater lenses located in the area. The study also showed that hydrocarbon pollutants were practically absent in the brackish water areas of central and southern Kuwait, except for a few isolated sites. However, nonpetroleum hydrocarbons, with ultraviolet-visible absorption characteristics and fluorescence characteristics typically associated with humic substances, were observed at a few sites in the brackish water fields.     

Factors of bacteria and virus transport in groundwater

The underground transport of pathogenic bacteria and viruses may be described by the general transport equation considering dispersion, adsorption, and biological elimination. The survival time of bacteria and viruses in groundwater is different for the specific species and for the specific groundwater environment. Dispersion causes a distribution of pollutants in time and space, thus their concentration decreases over time and with transport distance. Microorganisms are reversibly adsorbed on underground particles, which causes a retardation of their transport velocity with respect to groundwater flow velocity. An additional approach is provided by the filter theory. Presented at the International Symposium, International Association of Hydrogeologists, “Impact of Agricultural Activities on Ground Water Quality and Quantity,” Prague, Czechoslovakia, September, 1982.     

岩溶区地下水微生物污染特征及来源——以重庆南山老龙洞流域为例

文章选取老龙洞地下河流域10个地下水点采集样品,分析水样中的水化学指标和三种重要微生物指标,以了解城市化进程对老龙洞地下河流域水质的影响,探究该地区微生物污染的主要来源。结合岩溶区独特的水文地质条件,利用粪大肠杆菌（FC）与粪链球菌（FS）比值法,初步分析得到该地区微生物污染程度和污染来源。研究结果表明:（1）老龙洞流域地下水存在严重的微生物污染,地下水总细菌数、大肠菌群远超过国家地下水标准规定,分别是国家地下水标准规定的2.3×102～5.5×104倍、0.8×104～0.9×106倍,粪大肠菌群数量为100～4.38×106 CFU?L-1;（2）4#、6#采样点微生物污染主要来源于温血动物,1#、7#、8#采样点地下水受城市化进程的影响大;（3）微生物污染主要来源于人类粪便,同时SO42-、PO43-、NO3-含量高且与微生物污染相关性密切,说明生活污水引起的次生微生物污染较严重,2#、3#、5#、10#采样点受生活污水和禽畜粪便影响较小,属于单纯的NO3-农业污染型地下水,微生物污染较轻。      

地下水典型氧化还原敏感组分迁移转化的研究热点和趋势

C-N-S反应体系是地下水系统中氧化还原敏感组分循环和能量流动的关键系统,但它如何与Fe、Mn循环过程、相关功能微生物代谢路径耦合并控制氧化还原敏感组分的迁移转化却并不清楚。本文在对国内外相关文献进行归纳总结的基础上,把地下水中的氧化还原敏感组分分为氧化富集型和还原富集型,较为系统地梳理了地下水系统C、N、S循环驱动的典型氧化还原敏感组分(主要以U、Cr、Fe、As为例)迁移转化过程,指出了该领域的主要研究热点,包括C-N反应体系中典型氧化还原敏感组分的迁移转化、C-S反应体系中还原富集型组分活化和氧化富集型组分固定机理、典型氧化还原敏感组分之间的相互作用、微生物作用下典型氧化还原敏感组分的转化和富集等,并提出基于代谢路径的C-N-S反应体系及其驱动下地下水典型氧化还原敏感组分转化过程和富集机理,将成为本领域的发展趋势。     

Microbial degradation of chloroethenes in groundwater systems

The chloroethenes, tetrachloroethene (PCE) and trichloroethene (TCE) are among the most common contaminants detected in groundwater systems. As recently as 1980, the consensus was that chloroethene compounds were not significantly biodegradable in groundwater. Consequently, efforts to remediate chloroethene-contaminated groundwater were limited to largely unsuccessful pump-and-treat attempts. Subsequent investigation revealed that under reducing conditions, aquifer microorganisms can reductively dechlorinate PCE and TCE to the less chlorinated daughter products dichloroethene (DCE) and vinyl chloride (VC). Although recent laboratory studies conducted with halorespiring microorganisms suggest that complete reduction to ethene is possible, in the majority of groundwater systems reductive dechlorination apparently stops at DCE or VC. However, recent investigations conducted with aquifer and stream-bed sediments have demonstrated that microbial oxidation of these reduced daughter products can be significant under anaerobic redox conditions. The combination of reductive dechlorination of PCE and TCE under anaerobic conditions followed by anaerobic microbial oxidation of DCE and VC provides a possible microbial pathway for complete degradation of chloroethene contaminants in groundwater systems. Résumé Les chloroéthanes, tétrachloroéthane (PCE) et trichloroéthane (TCE) sont parmi les polluants les plus communs trouvés dans les aquifères. Depuis les années 1980, on considère que les chloroéthanes ne sont pas significativement biodégradables dans les aquifères. Par conséquent, les efforts pour dépolluer les nappes contaminées par des chloroéthanes se sont limités à des tentatives de pompage-traitement globalement sans succès. Des travaux ultérieurs ont montré que dans des conditions réductrices, des micro-organismes présents dans les aquifères peuvent, par réduction, dégrader les PCE et TCE en composés moins chlorés, comme le dichloréthane (DCE) et le chlorure de vinyl (VC). Bien que des études de laboratoire réalisées avec des micro-organismes adaptés aux composés halogénés montrent que la réduction complète en éthane est possible, dans la plupart des nappes la réaction de déchloration par réduction s'arrête apparemment au DCE et au VC. Cependant, des recherches récentes menées sur des sédiments d'un aquifère et d'alluvions ont démontré que l'oxydation microbienne de ces descendants réduits peut se produire de manière significative dans des conditions de redox anérobies. La déchloration par réduction de PCE et de TCE dans des conditions anérobies suivie par une oxydation microbienne anérobie des DCE et VC fournit une piste microbienne possible pour obtenir une dégradation complète des chloroéthanes polluants dans les aquifères. Resumen Los cloroetanos (tetracloroetano PCE y tricloroetano TCE) son contaminantes muy habituales en los acuíferos. Hasta 1980 se consideraba que los cloroetanos no eran biodegradables y, por tanto, los métodos de rehabilitación en acuíferos contaminados con cloroetanos se limitaban al pump-and-treat, generalmente con poco éxito. Posteriormente se vio que, en condiciones reductoras, algunos microorganismos pueden reducir PCE y TCE a unos subproductos menos clorados, como el dicloroetano (DCE) y el cloruro de vinilo (VC). Aunque estudios de laboratorio recientes sugieren que la reducción completa a etano es posible, en la mayoría de los sistemas acuíferos la decloración suele detenerse en los DCE o VC. Sin embargo, investigaciones más recientes en acuíferos y sedimentos fluviales demuestran que la oxidación microbiana de estos subproductos puede ser importante bajo condiciones redox anaerobias. La combinación de la reducción de PCE y TCE en condiciones anaerobias seguida de la oxidación microbiana anaerobia de DCE y VC proporciona un método potencial para la degradación total de los cloroetanos en los sistemas acuíferos.     

Application of conductance phenomenon in groundwater studies

In this article, we present an interesting behaviour of conductance in a basaltic terrain. We use vertical electrical sounding data carried out in Wenner configuration at dug well sites for data analysis. Geophysical phenomena observed in the sharply rising trends followed by negligibly rising trends of the conductance curves are discussed. The unique behaviour of conductance curve is used to estimate depth to the static water level in dug wells. The geophysically estimated depths to the static water levels are compared with the observed static water levels in the existing dug wells located at all sites of investigation. Water-level fluctuations observed in dug wells between two different periods coinciding with pre- and post-monsoon regimes are geophysically estimated by using the trends on the conductance curves. Depth to the static water levels is geophysically estimated at seven experimental sites located adjacent to dug wells and four virgin sites where there are no dug wells. Validation of the geophysically estimated static water levels and static water-level fluctuations shows encouraging results.     

Delineation of groundwater potential zones and electrical resistivity studies for groundwater exploration

The electrical resistivity method is widely used in groundwater exploration studies. The method is particularly well suited to carry out groundwater studies in hard-rock terrains. The popular Schlumberger method of electrode configuration was applied in the study area. In all, 112 vertical electrical soundings (VESs) were carried out at different locations in the study area. VES interpretations were used to generate a top-layer contour map and a depth-to-basement map. Finally, a groundwater quality/potential map for the study area was generated using the depth-to-bedrock map, a water-level fluctuation map, and the second-layer thickness. Furthermore, this groundwater potential map was classified into three sectors, i.e. poor, moderate and good zones with respect to the prospects of finding groundwater in the study area. This map has a practical value, as it provides guidance to farmers in selecting favourable well sites, thereby avoiding unnecessary financial losses.     

Colloid properties in granitic groundwater systems. I: Sampling and characterisation

Colloids are present in all groundwaters. The role they may play in the migration of contaminants in the geosphere must be studied. Colloid sampling and characterisation campaigns have been carried out in Switzerland. On the basis of the results obtained from studies in the Grimsel area (Grimsel Test Site, Transitgas Tunnel), Northern Switzerland (Leuggern, Zurzach) and the Black Forest (Bad Säckingen, Menzenschwand), a consistent picture is emerging.The groundwater colloids in granitic systems are predominantly composed of phyllosilicates and silica originating from the aquifer material. Under constant hydrogeochemical conditions, the colloid concentration does not exceed 100 ng·ml⁻¹ when the calcium concentration is larger than 10⁻⁴ M and the sodium concentration is larger than 10⁻² M. However, under transient chemical or physical conditions, such as geothermal or tectonic activity, colloid generation may be enhanced and the colloid concentration may reach 10 μg·ml⁻¹ or more if both calcium and sodium concentrations are low (i.e. < 10⁻⁴ M and < 10⁻² M respectively). The colloid size distribution yields information about their stability. For a representative deep crystalline water ([Ca] = 3.5 × 10⁻⁴ M, [Na] = 1.4 × 10⁻² M, [TOC] = 3 × 10⁻⁶ M), the colloid concentration is < 100 ng · ml⁻¹ and around 10 ng · ml⁻¹ in Zurzach water for sizes ranging from 100 to 1000 nm.     

Mobilization of natural arsenic in groundwater: targeting low arsenic aquifers in high arsenic occurrence areas

研究表明饮用水中微小数量的砷会对人类健康产生不利影响.世界上居住在贫穷地区的人数超过了100万,目前他们正直接饮用来自含水层中砷离子含量(>10μg/L)非安全标准的地下水.砷有时称为毒中之王,在水环境中常常以五价氧化物形式出现.自2000年以来,许多国家开始执行更为严格的10μg/L(WHO认可的居民安全饮水标准)饮用水标准,可以确定地说,在世界范围内的饮用水中检测到砷的情况越来越多.亚洲地区砷中毒的人数比世界其他地区总和还多.最受影响的地区位于南亚和东南亚富砷带,环绕恒河一雅鲁藏布江-梅克纳河三角洲及恒河平原上游的冲洪积扇含水层、红河三角洲、湄公河和伊洛瓦底江;在中国境内包括内蒙黄河冲积盆地,山西大同盆地、新疆准噶尔盆地,其中的地下水富含砷和氟化物而引发砷中毒和氟中毒.尽管还未完全掌握其中的水文地质及生物地球化学作用的详细过程,但对大多数沉积介质含水层,在还原条件下砷离子容易从沉积介质转移到地下水中.孟加拉研究实例表明地质时期尺度的冲刷降低了沉积介质中的As和有机物含量从而形成低砷地下水.这一认识为孟加拉国的降砷策略提供了科学指导,是未来水文学,矿物学,地质学和生物地球化学方面很有意义的研究方向,并有利于地砷病区低砷地下水的可持续利用.     

A geoelectrical-hydrogeochemical investigation of shallow groundwater occurrence in Ibadan, southwestern Nigeria

 An integrated geological, geoelectrical and hydrochemical investigation of shallow groundwater occurrence in the Ibadan area, southwestern Nigeria, is presented. The primary objective was to characterise the groundwater in a typical low-latitude environment underlain by Precambrian crystalline basement complex rocks. The dominant rocks comprise suites of gneisses and quartzites. Chemical analyses of the groundwater show that the mean concentration of the cations is in the order Na>Ca>Mg>K while that for the anions is Cl>HCO₃>NO₃>SO₄. Statistical analyses, using the product-moment coefficient of correlation, indicate positive correlations between the following pairs of parameters: TDS and conductivity (r=0.96); Na⁺+Mg²⁺ and Cl^– (r=0.95); Na⁺+K⁺ and Ca²⁺ (r=0.43); Na⁺+K⁺ and HCO₃ ^– (r=0.17); Ca²⁺ and Mg²⁺ (r=0.74); Ca²⁺ and HCO₃ ^– (r=0.33); Ca²⁺+Mg²⁺ and HCO₃ ^– (r=0.31) and pH and HCO₃ ^– (r=0.54). A very weak negative correlation was recorded between pH and Cl^–, with r=–0.003. Five groundwater groups have been identified, namely, (1) the Na-Cl, Na-Ca-Cl, Na-Ca-(Mg)-Cl; (2) the Ca-(Mg)-Na-HCO₃-Cl, Na-Ca-HCO₃-Cl, and Ca-HCO₃-Cl; (3) the Ca-(Mg)-Na-HCO₃, Ca-Na-HCO_3; (4) Ca-Na-Cl-(SO₄)-HCO₃ and (5) the Ca-(Mg)-Na-SO₄-HCO₃. The different groups reflect the diversity of bedrock types and consequently also of the products of weathering. Most of the water sampled is unfit for drinking on account of the high NO₃ ^– content. It can, however, be used for irrigation purposes as the sodium hazard is low while the salinity hazard ranges from low to medium. Resistivity soundings indicate the presence of a thick weathering profile, which could be up to 60 m. Such sites should be the target for any long-term and sustainable groundwater development in the area. Received: 15 April 1998 · Accepted: 4 July 1998     

西宁盆地储水构造及其地下淡水赋存规律研究

本文以近年来在西宁盆地人畜饮用供水地下水勘查示范工程取得的最新资料为基础,通过对区内碎屑岩类储水构造模式的研究,分析研究区内干旱缺水村镇地下淡水赋存规律与形成机理,以期为类似地区居民基本生活饮用水的解决提供依据.     

The impacts of pasture- and manure-spreading on microbial groundwater quality in carbonate aquifers

Hydrogeological and microbiological research is in progress to analyze the interaction between groundwater and microbial pollutants, produced by pasture and/or manure spreading, in the areas of different carbonate aquifers of southern Italy. Several springs and wells were studied, and the precipitation, the discharge, the groundwater level and the classic microbial indicators of pollution were monitored weekly or daily. The experimental results show that the pasture and the manure spreading produced microbial contamination of the groundwater, even if runoff infiltration in swallow holes does not exist. The time dependence of microbial contamination shows a series of peaks irregularly distributed, related to the precipitation that produce effective infiltration.     

Applicability and methodology of determining sustainable yield in groundwater systems

There is currently a need for a review of the definition and methodology of determining sustainable yield. The reasons are: (1) current definitions and concepts are ambiguous and non-physically based so cannot be used for quantitative application, (2) there is a need to eliminate varying interpretations and misinterpretations and provide a sound basis for application, (3) the notion that all groundwater systems either are or can be made to be sustainable is invalid, (4) often there are an excessive number of factors bound up in the definition that are not easily quantifiable, (5) there is often confusion between production facility optimal yield and basin sustainable yield, (6) in many semi-arid and arid environments groundwater systems cannot be sensibly developed using a sustained yield policy particularly where ecological constraints are applied. Derivation of sustainable yield using conservation of mass principles leads to expressions for basin sustainable, partial (non-sustainable) mining and total (non-sustainable) mining yields that can be readily determined using numerical modelling methods and selected on the basis of applied constraints. For some cases there has to be recognition that the groundwater resource is not renewable and its use cannot therefore be sustainable. In these cases, its destiny should be the best equitable use.

Scale aspects of groundwater flow and transport systems

Flow-system analysis is based on the concept of hierarchical groundwater flow systems. The topography of the water table, which is strongly related to the topography of the land surface, is a major factor in the hierarchical nesting of gravity-driven groundwater flow, resulting in flow systems of different orders of magnitude in lateral extent and depth of penetration. The concept of flow systems is extremely useful in the analysis of spatial and temporal scales and their mutual relationships. Basic equations on the laboratory scale are extended to larger, regional scales. Making use of Fourier analysis further develops Tóth's original idea of topography-driven flow systems. In this way, the different spatial scales of the water table are separated in a natural way, leading to a simple expression for the penetration depth of a flow system. This decomposition leads also to the relationship between spatial and temporal scales. Analogous to flow systems, water bodies with different water quality may be called 'transport systems.' Field studies, numerical micro-scale modeling over macro-scale domains, and stochastic dispersion theory indicate that between systems with steady transport, the interfaces are relatively thin. The interfaces are much thinner than the relatively large mixing zones predicted by the conventional engineering approach to macrodispersion, in which relatively large, time-independent macrodispersion lengths are applied. A relatively simple alternative engineering approach is presented. For macrodispersion of propagating solute plumes, the alternative dispersion term gives the same results as the conventional engineering approach and gives correct results for steady-state transport.