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1.
Geoenvironmental site investigation using different techniques in a municipal solid waste disposal site in Brazil 总被引：3，自引：0，他引：3
Giulliana Mondelli Heraldo Luiz Giacheti Maria Eugênia Gimenez Boscov Vagner Roberto Elis Jorge Hamada 《Environmental Geology》2007,52(5):871-887
Different geoenvironmental site investigation techniques to assess contamination from a municipal solid waste disposal site
in Brazil are presented here. Superficial geophysical investigation (geoelectrical survey), resistivity piezocone penetration
tests (RCPTU), soil samples collected with direct-push samplers and water samples collected from monitoring wells were applied
in this study. The application of the geoelectrical method was indispensable to identify the presence and flow direction of
contamination plumes (leachate) as well as to indicate the most suitable locations for RCPTU tests and soil and water sampling.
Chemical analyses of groundwater samples contributed to a better understanding of the flow of the contaminated plume. The
piezocone presented some limitations for tropical soils, since the groundwater level is sometimes deeper than the layer which
is impenetrable to the cone, and the soil genesis and unsaturated conditions affect soil behavior. The combined interpretation
of geoelectrical measurements and soil and water samplings underpinned the interpretation of RCPTU tests. The interpretation
of all the test results indicates that the contamination plume has already overreached the landfill’s west-northwest borders.
Geoenvironmental laboratory test results suggest that contamination from the solid waste disposal site has been developing
gradually, indicating the need for continuous monitoring of the groundwater. 相似文献
2.
Ge Chen Yajun Sun Jiayu Liu Shougan Lu Ling Feng Xiang Chen 《Environmental Earth Sciences》2018,77(24):797
The simulation of groundwater flow and solute transport at contaminated sites often neglects the important influence that aquifer heterogeneity can have on the sub-surface distribution of contaminants. In this paper, the method of transition probability for geological statistics (T-PROGS) included in the Groundwater Model System (GMS) was applied to a chlor-alkali-contaminated site that was sampled with 68 soil borings and 15 groundwater monitoring wells. A 3-D groundwater numerical model and solute transport model was developed that was constrained by soil and groundwater data from the site. The spatial distribution of chloroethylene concentrations was simulated for a number of times using the levels measured in the field as a baseline. The results of these simulations showed that shapes and distribution of contaminant plumes are irregular both vertically and horizontally. The solute-transport simulations indicated that much of the contamination will preferentially move in groundwater through silt and fine-sands whereas flow is largely blocked in clays. Consequently, fine sand and silts become the most seriously polluted zones at the site, whereas, areas underlain by clays are largely uncontaminated. Heterogeneous lithologies beneath a site increase the complexity of coupling simulations of soil and groundwater. 相似文献
3.
Effects of historical mining activities on surface water and groundwater - an example from northwest Arizona 总被引：5，自引：3，他引：2
Ulrike Rösner 《Environmental Geology》1998,33(4):224-230
The focus of this research was to determine the impact of abandoned mines on surface water and groundwater in the historical
mining districts of the Cerbat Mountains, Arizona. The surface water in the mining areas was found to be contaminated by various
combinations and concentrations of heavy metals. Elevated arsenic, cadmium, and iron concentrations were detected in most
surface-water samples, while lead, copper, and zinc contamination differed from region to region, depending on the ore mined.
The groundwater was seriously polluted by arsenic, cadmium, lead, zinc, iron, and manganese in the immediate vicinity of mines
that processed ore on the site, such as the Tennessee Mine near Chloride. Chloride's groundwater, however, showed no evidence
of contamination. Three possible explanations are discussed: immobilization of the heavy metals in the soil by chemical reactions
and adsorption, dilution effects due to the rainy season in spring, or the existence of different groundwater systems.
Received: 17 September 1996 · Accepted: 14 May 1997 相似文献
4.
Contaminated ground and contaminated estuary sediment illustrated by two case histories 总被引：1，自引：0，他引：1
Contaminated ground forms a problem in all of the industrialized countries of the world. Contaminated ground may give rise
to hazards and that implies a degree of risk which also involves a problem of definition. The investigation of a site which
is suspected of being contaminated differs somewhat from a routine site investigation. Sampling of soil, groundwater and gas-producing
material may be required. Various precautions may be necessary to do this and personnel may have to wear protective clothing.
The first case history considered involves a site investigation for a relief sewer in Glasgow. As the site investigation progressed
it ran into made-ground which contained chemical waste. The presence of this waste meant that the nature of the investigation
changed and much more stringent safety precautions had to be taken. It also meant that the initial location of the sewer tunnel
had to be repositioned at greater depth in uncontaminated sandstone rather than in the superficial deposits above.
The other case history considers the contamination of sediments in the Forth Estuary. When trace metals are released into
the water column they can be transferred rapidly to the sediment phase by adsorption onto suspended particulate matter, followed
by sedimentation. Intertidal flats may be considered as important trace metal sinks since they accumulate large amounts of
suspended matter. Hence, in polluted estuaries the deposition of suspended particles on intertidal flats may thus cause severe
contamination. The Forth Estuary has unique contamination for British estuaries; it is experiencing significant Hg pollution.
In addition, due to the presence of a nuclear submarine base in the Forth Estuary, 60Co is detectable in the intertidal sediments. Temporal and spatial contamination patterns were analysed in relation to historical
and present pollution point sources. The effect of fluvial and marine sediment mixing on trace metals and other processes
controlling contaminant levels is reviewed. Preliminary results on quantifying sediment accretion rates using Caesium levels
are discussed.
Received: 9 August 1996 · Accepted: 17 December 1996 相似文献
5.
6.
Contamination of groundwater by enteric pathogens has commonly been associated with disease outbreaks. Proper management and treatment of pathogen sources are important prerequisites for preventing groundwater contamination. However, non-point sources of pathogen contamination are frequently difficult to identify, and existing approaches for pathogen detection are costly and only provide semi-quantitative information. Microbial indicators that are readily quantified often do not correlate with the presence of pathogens. Pathogens of emerging concern and increasing detections of antibiotic resistance among bacterial pathogens in groundwater are topics of growing concern. Adequate removal of pathogens during soil passage is therefore critical for safe groundwater extraction. Processes that enhance pathogen transport (e.g., high velocity zones and preferential flow) and diminish pathogen removal (e.g., reversible retention and enhanced survival) are of special concern because they increase the risk of groundwater contamination, but are still incompletely understood. Improved theory and modeling tools are needed to analyze experimental data, test hypotheses, understand coupled processes and controlling mechanisms, predict spatial and/or temporal variability in model parameters and uncertainty in pathogen concentrations, assess risk, and develop mitigation and best management approaches to protect groundwater. 相似文献
7.
Mohamed Metwaly Eslam Elawadi Sayed S. R. Moustafa Nassir Al Arifi Mohamed El Alfy EKab Al Zaharani 《Environmental Earth Sciences》2014,71(2):827-835
Groundwater contamination is one of the most significant problems in arid countries. Al-Quwiy’yia region is an example of an area where the groundwater is contaminated as a result of infiltration of waste water in low-lying areas adjacent to inhabited zones. Such contamination poses significant environmental threats for the surrounding environment and groundwater. Surface observations and spatial distribution of contamination observed in the shallow aquifer indicate that the main contamination sources were from sewage as well as from waste water dumping. However, the main source of water supply for the whole area is groundwater abstracted from the relatively shallow aquifer. Therefore, the transient electromagnetic method (TEM) and 2D electrical resistivity tomography (2D ERT) have been applied close to the waste water dump site to characterize the response of pollution plumes. Both of these geoelectrical techniques are sensitive to electrical conductivity as well as to other physical properties, which are greatly influenced by the polluted groundwater. Therefore, it is possible to profile the contamination plumes, both vertically and horizontally, in the vicinity of the measured stations. The ERT profiles gave detailed information about the lateral distribution of the contaminated groundwater, whereas the TEM demonstrated the vertical extensions. 相似文献
8.
The temporal and spatial characteristics of groundwater recharge in urban environments remain poorly understood. Depth-specific
monitoring of groundwater quality in the Triassic Sandstone underlying the city of Nottingham, UK, indicates that contamination
results primarily from sewage and atmospheric sources. The temporal and depth-specific characteristics of microbial and inorganic
(e.g. nitrate, chloride, sulphate) contamination over the investigation period differ significantly and reflect the contrasting
transport characteristics of surface-loaded solutes and particulate microbial species (bacteria and viruses) in the Triassic
Sandstone. Differences result from a variety of factors, which include microbial die-off, dilution, and the contaminant-source
characteristics. Observations in this study show that low levels of microbial contamination should be expected at depth in
fissured sandstone due to aquifer heterogeneities such as fissuring and the occurrence of mudstone bands, though the magnitude
of this contamination will vary over time. Furthermore, urban groundwater-protection measures based on solute-transport estimates
may not be applicable to microbial contamination.
Electronic Publication 相似文献
9.
10.
Groundwater recharge: an overview of processes and challenges 总被引：11，自引：13，他引：11
Since the mid-1980s, a relative explosion of groundwater-recharge studies has been reported in the literature. It is therefore
relevant to assess what is now known and to offer further guidance to practitioners involved in water-resource development.
The paper summarizes current understanding of recharge processes, identifies recurring recharge-evaluation problems, and reports
on some recent advances in estimation techniques. Emphasis is accorded to (semi-)arid regions because the need for information
is greatest in those areas – groundwater is often the only water source, is vulnerable to contamination, and is prone to depletion.
Few studies deal explicitly with groundwater recharge in temperate and humid zones, because recharge is normally included
in regional groundwater investigations as one component of the water balance. The resolution of regional water-balance studies
in (semi-)arid areas is, in contrast, often too low to quantify the limited recharge component with sufficient precision.
Despite the numerous studies, determination of recharge fluxes in (semi-)arid regions remains fraught with uncertainty. Multiple
tracer approaches probably offer the best potential for reliable results in local studies that require 'at-point' information.
However, many investigations indicate that these approaches are not straightforward, because in some cases preferential flow
contributes as much as 90% of the estimated total recharge. Tracer results (e.g. Cl–, 3H) must therefore be interpreted with care in areas with multi-modal flow in the vadose zone. Moreover, accurate estimation
of total chloride deposition is essential, and tritium may be influenced by vapour transport at low flux rates. In addition,
paleoclimatic and paleohydrological conditions may cause discrepancies between measured actual processes and calculated long-term
averages.
The frequently studied issues of localized recharge and spatial variability need not be a problem if concern is with regional estimates. The key for practitioners is
the project objective, which dictates whether 'at-point' or area-/groundwater-based estimation methods are appropriate. Many
indirect (wadi) recharge studies reported in the literature are site specific; the relationship between 'at point' hydraulic properties
and channel-reach losses demands further investigation.
Electronic Publication 相似文献
11.
高精度测定渗透系数（K）的重要性不言自明,但是现阶段野外试验手段能够提供的关于K的信息不能满足高度非均质地层中污染物迁移预测模拟的需求。直接推进注入记录器(Direct Push Injection Logger, DPIL)和直接推进渗透仪(Direct Push Permeameter, DPP)是新发展的水文地质参数测量仪器,能够使K值的测定达到前所未有的分辨率和成本效益水平。工具向地下推进过程中,通过对注水量、注水压力和其它的水文地球物理参数的同步监测,直接推进技术(Direct Push, DP)能快捷准确地获得地层渗透系数的垂向分布。DP技术几乎适用于所有野外松散地层,并且对场地的干扰很小。因此,它克服了许多基于既有井的传统含水层测试方法的局限性。最近在美国MADE试验场的一个案例研究表明,使用DPIL/DPP可以获得空间分辨率达15cm的K值垂向分布。未来,高精度直接推进技术还可以与新一代的地球物理技术,例如高精度探地雷达相结合,以实现不同位置DP测定K值的互联以及整个试验场K值三维分布的确定。 相似文献
12.
R. Ian Acworth Gabriel C. Rau Mark O. Cuthbert Evan Jensen Keith Leggett 《Hydrogeology Journal》2016,24(4):905-921
Quantifying dryland groundwater recharge as a function of climate variability is becoming increasingly important in the face of a globally depleted resource, yet this remains a major challenge due to lack of adequate monitoring and the complexity of processes involved. A previously unpublished and unique dataset of high density and frequency rainfall measurements is presented, from the Fowlers Gap Arid Zone Research Station in western New South Wales (Australia). The dataset confirms extreme spatial and temporal variability in rainfall distribution which has been observed in other dryland areas and is generally explained by the dominance of individual storm cells. Contrary to previous observations, however, this dataset contains only a few localised storm cells despite the variability. The implications of spatiotemporal rainfall variability on the estimation of groundwater recharge is assessed and show that the most likely recharge mechanism is through indirect and localised, rather than direct, recharge. Examples of rainfall and stream gauge height illustrate runoff generation when a spatially averaged threshold of 15–25 mm (depending on the antecedent moisture conditions) is exceeded. Preliminary assessment of groundwater levels illustrates that the regional water table is much deeper than anticipated, especially considering the expected magnitude of indirect and localised recharge. A possible explanation is that pathways for indirect and localised recharge are inhibited by the large quantities of Aeolian dust observed at the site. Runoff readily occurs with water collecting in surface lakes which slowly dry and disappear. Assuming direct groundwater recharge under these conditions will significantly overestimate actual recharge. 相似文献
13.
The present work demonstrates the environmental problems associated with the development and operation of a lined and unlined
landfill site, both used for municipal solid waste landfilling, that are situated next to the city of Patra, Greece. Findings
from a detailed site investigation as well calculations on hydrologic evaluation of landfill’s performance and measurements
on leachate composition proved that the lined landfill site is more secure and environmental friendly compared with the unlined
landfill site. Even though, until today, there is no evidence from near boreholes for severe contamination problems generated
by any of the two landfills, in the forthcoming future several environmental problems are expected to occur from the unlined
site. In addition the prevailing hydrogeotechnical conditions indicated that the unlined site is a potential source of contamination;
hence extra remedial measures should be received by the local authorities to prevent severe contamination in soil and groundwater. 相似文献
14.
地下水有机污染物监测技术的研究现状 总被引：7，自引：2，他引：5
地下水中有机污染物就其危害而言排在所有污染物的首位。针对目前地下水有机污染物监测技术的研究现状与发展进行了综述。分别对地下水有机污染物的前处理技术及常用的几种测定技术进行了分析阐述,并提出建立检测限更低的分析方法,及时了解地下水中低浓度有机污染物等3个方向的技术发展前景。 相似文献
15.
通过分析、对比发达国家场地污染调查与风险评价技术流程的大量信息,结合工作实践,充分考虑我国的实际情况,视土壤和地下水为相互联系的一个整体,提出了我国现阶段场地尺度土壤和地下水污染调查与风险评价的技术程序和工作内容。 相似文献
16.
Hydrogeochemistry of Urban Floodplain Aquifer Under the Influence of Contaminated River Seepage in Delhi (India) 总被引：1，自引：0，他引：1
Hydrogeochemical and hydrodynamic surface/groundwater interactions were investigated at the urban floodplain aquifer in Delhi, India. The heavily polluted Yamuna River is in hydraulic contact to the groundwater and river seepage results in a contamination plume. A conceptual redox zonation was developed based on the occurrence or absence of terminal electron acceptors. The redox zonation shows an inverted zonation from sulphate-reducing conditions close to the river over manganese- and iron-reducing conditions to a mixed oxic/suboxic zone. This study shows that the occurrence of problematic substances such as ammonium and arsenic in the groundwater is a consequence of the high load of untreated sewage in the river in combination with losing river conditions. Sequential extraction of aquifer material was performed to obtain information on geochemical availability of arsenic associated with different mineral phases and binding forms. Geogenic and anthropogenic arsenic sources contribute to overall arsenic concentration, and arsenic is found to be attributed mainly to amorphous iron oxide and sulphidic phases in the sediment. The contamination plume at the urban floodplain aquifer makes the groundwater unfit for drinking water purposes. 相似文献
17.
Edouard Palis Thomas Lebourg Maurin Vidal Clara Levy Emmanuel Tric Mickael Hernandez 《Landslides》2017,14(4):1333-1343
The geology of the “Vence” landslide (0.8 million m3, south-eastern France) explains the complex hydrology of the site which plays a key role in the destabilization of the slope (water circulation within the sliding mass, fluid exchanges between superficial layers and deep karstic aquifer through faults). To understand fluid circulations within the unstable slope, a 9.5-year multi-parametric survey was set up. The survey combines electrical resistivity tomography (daily acquisition), rainfall records since 2006 and boreholes monitoring groundwater level since 2009. The objective of this work is to present an automated clustering analysis applied to the ERT data enabled to locate geological units displaying distinct hydrogeological behaviours. Clustering analysis, based on a hierarchical ascendant classification (HAC), helped to simplify the ERT section isolating three groups of apparent resistivity values. Comparing the variations of these clusters’ behaviours in time to the variations of the groundwater levels on site, we identified hydrogeological units. The role of the faults cutting the substratum is thereby highlighted. It is the simultaneous analysis of such a large real dataset that allowed obtaining robust results characteristic of the long-term behaviour of the natural hydrogeological system. This type of qualitative information on the variability of the slope hydrogeological behaviour both spatially and temporally is crucial to help improving the conversion of resistivity data into hydrologic quantities. Indeed, the definition of petrophysical models to convert ERT measurements into hydrological measurements should be site-specific and take into account the spatial and temporal variability of the medium. In this work, we show a method that can also help to focus on the areas in depth that have different levels of permeability and observe how the saturation degree evolves in time. This can be used to optimize the location of additional instrumentation (such as temperature probes and chemical sampling) and, thus, help in the prevention of the risk in such problematic areas. 相似文献
18.
A model for the assessment of aquifer contamination potential based on regional geologic framework 总被引：2，自引：0，他引：2
The texture and three-dimensional framework of geologic materials should be considered in assessments of groundwater's vulnerability to contamination because geology controls the movement of contaminants and groundwater and influences groundwater quality. Contaminants are introduced into, transmitted through, and stored by geologic materials. We present a model that identifies aquifers and ranks sequences of geologic materials by their relative potential for transmitting water and contaminants from land surface. With this basis, the model can be used to assess the potential for contamination of aquifers by surface activities such as landfitling of wastes or application of agricultural chemicals. A regional map of aquifer contamination potential can be generated from the model; it retains the geologic map information intact and available for reinterpretation or other uses.The model was developed using broad, regional map information and is intended to be a general tool for assessing the regional vulnerability of aquifers to contamination. It is not intended for local, site-specific use, but for prioritizing local areas where contamination potential and/or land-use history warrant more detailed assessment or monitoring. Because it provides a regional view of contamination potential, regional patterns or trends of map units should be evaluated, rather than using the map information literally to assess local areas. Methods of applying this model and contamination potential map to groundwater protection and management are currently being studied; research includes an attempt to statistically validate the model with water-quality data, and to identify natural groupings of the ranked contamination potential map units. 相似文献
19.
20.
由于工业与化工企业违规排放废（污）水,造成了场地区域土壤与水资源的污染,在后期污染场地环境调查评价中,地下水污染深度界定尤为重要,地下水污染深度是地下水健康风险评估的主要依据。在河北省沧县某化工厂污染场地环境调查中,采用锥形止水器进行2层坐封式有效分层止水,准确界定地下水的污染深度。结合该工程实例,阐明分层止水器的分层止水技术进行第四系地下水污染深度调查、界定的技术方法。实践证明,该技术具有施工简单、使用灵活等优点,止水效果良好,技术有效、可行。 相似文献