共查询到20条相似文献，搜索用时 31 毫秒
1.
Suspended sediments in the Kharaa River catchment (Mongolia) and its impact on hyporheic zone functions 总被引：2，自引：2，他引：0
Melanie Hartwig Philipp Theuring Michael Rode Dietrich Borchardt 《Environmental Earth Sciences》2012,65(5):1535-1546
A previous study investigating the ecological status of the Kharaa River in Northern Mongolia reported fine-grained sediments
as being a major stress factor causing adverse impacts on the benthic ecology. However, the source of these sediments within
the catchment as well as the specific impact on hyporheic zone functions in the Kharaa River remained unclear. Therefore,
the objective of the current study was to investigate the underlying source–receptor system and implement an integrated monitoring
approach. Suspended sediment sources within the Kharaa catchment were identified by using extensive spatially distributed
sediment sampling and geochemical and isotope fingerprinting methods. On the receptor side, the ecological implications across
a gradient of fine-grained sediment influx were analyzed using a distinct hyporheic zone monitoring scheme at three representative
river reaches along the Kharaa River. Results of suspended sediment source monitoring show that during snowmelt runoff, riverbank
and gully erosion were the dominant sources. During the summer period, upland erosion contributed a substantial share of suspended
sediment. Fine-grained sediment influx proved to be the cause of habitat loss in the hyporheic zone and benthic oxygen production
limitation. This combined catchment and in-stream monitoring approach will allow for a better understanding and spatially
explicit analysis of the interactions of suspended sediment transport and hyporheic zone functioning. This information has
built the basis for a coupled modeling framework that will help to develop efficient management measures within the Kharaa
River basin with special emphasis on rapidly changing land-use and climatic conditions. 相似文献
2.
N. Özlü 《Mineralium Deposita》1983,18(3):469-476
This work deals with a concise but comprehensive study of trace-element distribution in the bauxite deposits of Mediterranean belt. Although the alloctonous and mainly detritic characters of several “karst bauxite” deposits are well established, their parent rock has remained largely enigmatic. Evidence is available that some chemical elements, notably Zr, Cr and Ga are largely immobile during the weathering and diagenesis and study of such trace-elements in “karst bauxites” permits to make an approach to the lithological nature of their parent rocks. It is shown, by reference to analyses of bauxites from Mediterranean areas, that all the deposits studied are aligned from a Cr rich pole related to ultramafics to another pole rich in Ga and Zr contents and in genetical relation with acidic parent rocks. The results obtained by this way have been controlled by application of “trace-element accumulation coefficient” which permits to distinguish four principal zones of bauxite derived from the parent rock of different lithological characters (Fig. 3). 相似文献
3.
Richter Dominik Goeppert Nadine Zindler Björn Goldscheider Nico 《Hydrogeology Journal》2021,29(5):1965-1978
Karst aquifers in subtropical regions are characterized by high variability of water availability and quality due to changes associated with rainy and dry seasons. An additional challenge for water management is the combination of surface-water and karst groundwater systems since high spatiotemporal dynamics cause high variability of water quality. In these cases, adapted protection strategies are required. In this study, a protection approach for the catchment of a river-water diversion point in a rural area in northern Vietnam is developed. The variability of water quality was evaluated by rainy and dry season synoptic surveys of suspended particles and microbial contamination at 49 sites and time series at three sets of paired sites under constant hydraulic conditions. The anthropogenic land-use activities in the catchment were mapped to identify potential contamination sources and to highlight the challenging combination of surface-water and karst groundwater management. The analyzed data indicate differences in water quality between the dry and rainy seasons and a higher influence on water quality from land use than from hydrologic conditions. Furthermore, the results suggest a high risk of contamination resulting from residential areas, agriculture, and livestock farming, and reveal the necessity of implementation of appropriate measures such as restricted farming and the hook-up of buildings to municipal sewage disposal. Finally, the data show that water quality can be improved by adjusting water withdrawals by the time of day. The applied methods can be transferred to other surface-water and karst groundwater systems in similar subtropical environments.
相似文献4.
Sediments have been used to detect sources of contamination in a catchment of the Port Jackson (Sydney Harbour) estuary and
to evaluate the effects of different land-use practices on the fluvial environment. Mean enrichment (mean concentrations over
pre-anthropogenic background) of size-normalized (<62.5 μm) aquatic sediment is 10 × for Cu, 20× for Pb and 90× for Zn adjacent
to industrialized areas and 2×, 7× and 7×, respectively for these metals in highly urbanized subcatchments. Diffuse sources
contribute minor metals to fluvial sediment even in the most underdeveloped subcatchment (2×, 3× and 3× for Cu, Pb and Zn
respectively). Organochlorine pesticide residue concentrations parallel heavy-metal trends due to a common mixed industrial
base. Effects-based sediment criteria suggest that some adverse biological impacts are probably occurring in streams flowing
through the industrial areas. This interpretation is supported by sequential extraction data which show that a moderate proportion
of total heavy metals, especially Zn, is associated with the more bioavailable exchangeable/adsorbed phases in these aquatic
sediments. High total suspended solid loads in water downstream of one of the industrial centers, and high particle-bound
Cu and Pb concentrations, suggest that most contaminants exiting the catchment do so in association with the solid phase.
Received: 29 March 1999 · Accepted: 30 August 1999 相似文献
5.
E. Dimitriou A. Mentzafou S. Zogaris M. Tzortziou K. Gritzalis I. Karaouzas Ch. Nikolaidis 《Environmental Earth Sciences》2012,66(7):1839-1852
Implementing efficient water resources management plans at trans-boundary river catchments is a difficult task that requires strong international cooperation, intensive monitoring programs, and common understanding of the impacts imposed on water resources by human pressures. Evros River, which flows through Bulgaria, Greece, and Turkey, is an ecologically important water body, protected by international legislation but nevertheless it is susceptible to numerous significant pollution sources that may lead to the deterioration of its environmental status. In this study, a water monitoring program was applied, incorporating chemical and biological parameters to assess the environmental status in the Greek part of the river and identify the associated pollution pressures. For this purpose, seasonal water sampling occurred in 13 sites along the longitudinal course of the river and a series of parameters were recorded including nutrients, heavy metals, microbiological loads, macroinvertebrate, and fish assemblages and abundance. The results indicated that the water quality of Evros River illustrate substantial spatiotemporal fluctuations, which can be well related to specific human activities and associated pressures. Therefore, a trans-boundary monitoring program should be initiated that will provide continuous information for the development and revision of the catchment’s adaptive management plan in order to restrict pollution impacts and achieve a good ecological status as required by the Water Framework Directive 2000/60EC. 相似文献
6.
Y. Vystavna D. Diadin V. Yakovlev J. Hejzlar I. Vadillo F. Huneau M. F. Lehmann 《Environmental Earth Sciences》2017,76(13):463
A combined hydrochemical and stable isotope approach was used to investigate the origin of nitrate in the shallow unconfined groundwater of Kharkiv city, Eastern Ukraine. The contamination was investigated in the context of land use within the catchment area. The observed enrichment of sulfate, chloride and nitrate suggests significant groundwater contamination in the shallow urban aquifer, which is widely used as drinking water source for the urban population. Characteristic nitrate/chloride ratios as well as stable isotope ratios (N and O) of nitrate in the most contaminated springs confirmed that septic waste from leaky sewer systems was the main source of nitrate contamination in the groundwater. Nitrate contamination is linked to the type of land use and sewage treatment regime in the catchment area. It is also modulated by the regional hydrogeology, which determines the susceptibility of a given aquifer toward groundwater pollution. A more quantitative assessment of nitrate sources based on the nitrate isotope analysis alone is rather difficult. However, our study confirms that the combination of hydrochemical tracers, robust land-use analysis and nitrate stable isotope measurements represents a valuable approach to identify the origin of the nitrate contamination. 相似文献
7.
基于第二十二届国际大地测量与地球物理大会的动态,分析出世纪之交水文学研究的三大基本特点.其一是强调人类活动对水循环的影响的研究,主要表现为研究土地利用变化对来自面源的氮负荷的影响、城市化进程加快对地表和地下水质的影响、河流对水文系统、泥沙输送及营养负荷的变化的生态响应和地下水和地表水在质与量上的相互作用.其二是十分重视区域尺度的水文的研究.包括区域及全球尺度资料库的建立和区域水分通量的计算.其三是集成应用示踪剂、遥感及先进的水文测验技术进行水文机理研究. 相似文献
8.
Plausible forms of fluoride (F) responsible for the persistence of fluoride toxicity in ground water of a granitic terrain
of semi-arid region, which is the main source of drinking water, have been studied. The study area in Anantapur District of
Andhra Pradesh, India, is one of the chronic regions with excess fluoride in groundwater and the region is under transformation
into aridity due to poor rainfall and over-exploitation of groundwater. Geochemical analysis of soil, groundwater, and rock
samples of the study area revealed the presence of other toxic elements also in addition to fluoride which need to be addressed
in drinking water sector in near future. Soil fluoride leaching experiments demonstrated the probable mode of mobilization
of F into the groundwater through natural recharge process during monsoon. Analysis of saturation indices indicates that the
fluorite solubility alone is not attributable to the high fluoride content in groundwater. The groundwater flow controls fluoride
mobilization in the study area as it is evidenced through fluoride concentration and electrical conductivity increase from
catchment to downstream region. Creation of lesser fluoride groundwater sources through rainwater harvesting and artificial
recharge of groundwater in catchment areas is suggested as a long-term sustainable safe drinking water strategy. 相似文献
9.
岩溶地区土地利用变化的水文响应研究——以贵州后寨河流域为例 总被引：3，自引：0，他引：3
以贵州普定后寨地下河流域为研究区,在分析流域生态环境特征以及岩溶水形成机制的基础上,通过野外调查、资料收集并结合现代空间技术、地理信息系统和遥感技术,研制开发了适合我国后寨河流域的基于落水洞的岩溶半分布式水文模型,分析了土地利用/覆被变化对流域径流的影响以及流域产汇流参数对比关系。结果表明:生态建设后除最大土壤蓄水量增大外,其它产流参数变化不大;汇流参数基本小于生态建设前,但相差不大;在降雨条件不变的情况下,生态建设后的产流量小于生态建设前的产流量,生态建设前土地覆被下的流量在低水位时比生态建设后的流量稍高,而在高水位时生态建设前流量比生态建设后的流量稍低。 相似文献
10.
Shellfish production areas are often located in shallow estuarine and coastal systems impacted by fluxes of faecal indicator organisms (FIOs) that exhibit extreme spatial and temporal variability. FIO abundance and distribution in the marine environment are determined by the combined effects of light intensity, water mixing, sewage content and suspended particulate matter. Favourable conditions for FIO survival are low solar radiation, low temperature, low salinity, low densities of micro-predators and high levels of organic matter. Rainfall is the parameter most commonly associated with peak levels of FIOs. Resuspension of contaminated sediments in the water column dominates FIO distribution in shallow and depositional estuaries during storm conditions. Water/flesh FIO ratios may differ between shellfish growing waters because salinities and water temperatures also influence filter-feeding activity. Data are lacking on the role of biological processes on FIOs uptake and clearance in shellfish, particularly during periods of good water quality. FIO accumulation is usually of higher magnitude in mussels and cockles than in oysters and surf clams. It is proposed that differences in FIO accumulation rates are associated with the biological activity and the position of shellfish in the water column in relation to the location of impacting pollution sources. Accurate information on catchment hydrology, land uses, FIO loads from sewerage-related sources and livestock production areas are required to adequately characterise the microbiological status of shellfisheries. 相似文献
11.
Define a protected buffer zone for Ismailia Canal, Egypt using Geographic Information Systems 总被引：1，自引：0，他引：1
Kamal O. Ghodeif Mohamed O. Arnous Mohamed H. Geriesh 《Arabian Journal of Geosciences》2013,6(1):43-53
Ismailia Canal is the principle source of drinking water supply to Suez Canal and Sinai governorates. However, Ismailia Canal is endangered from unwise activities in the surrounding environment. Drinking water resources protection can be implemented using land-use monitoring system or through land-use controls based on hydrogeologic mapping to study the impacts of development on water quality. Our approach is to protect the direct and indirect catchment areas for surface water supply, especially the sensitive areas, those that are more vulnerable to contamination than other areas. Remote sensing and geographic information system techniques are applied to construct and integrate the hydrogeological data, inventory for potential sources of contamination and mapping the sensitive areas in order to construct the a protected buffer zone for Ismailia Canal, and to constrain the development activities in all the surrounding areas of surface water supply. The sensitive areas are delineated, where extra protection is required, based on soils properties, geology, and specific hydrogeological criteria. Industrial areas, drains, and septic tanks in the surrounding villages are the common potential sources of contamination. The hydrologic relation between Ismailia Canal and groundwater has great variations. Comprehensive plan for water protection were composed. It includes maintaining three natural protection zones of at least 300-m width along the main course of the Canal and delineating vulnerable zones depending on the aerial extension of the sensitive areas within 10 km on both sides of the Canal. Specific protection measures are recommended over the sensitive areas. The natural ecosystems of swamps around Ismailia Canal should be conserved and the processes of continuous burial prevented. 相似文献
12.
《Applied Geochemistry》2006,21(8):1362-1375
Pumice has been used as a serviceable abrasive or religious artifact since antiquity and has therefore been an object of trade. By analyzing pumice samples from archaeological excavations and comparing the results to an analytical database, it is possible to establish the origin of the sample and thereby get information on the maximum age and the transport route of the pumice sample. In addition, the deposition of primary tephra deposits can be used as time markers, and place constraints on the ages of archaeological materials.Neutron activation analysis (NAA) was applied to determine the concentrations of 25 elements (As, Ba, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Th, U, Yb, Zn and Zr) in pumice samples from the Mediterranean region: Milos, Santorini, Kos, Giali and Nisyros (Greece), Lipari (Italy) and Cappadokia (Turkey). It was found that eruption products like pumice or volcanic ash can be correlated in many cases to their volcanic sources by comparison of the typical main- and trace-elemental concentration patterns (“chemical fingerprint”). Such a distinction is possible if the volcanic rocks are homogenous enough with respect to the concentrations of geochemically relevant elements. Using only the pure glass fraction of tephra, a sample size of 5 mg is sufficient for identification by NAA. 相似文献
13.
“Mallines” (wet-meadows) are Patagonian ecosystems that provide hydrological, biological and scenic resources. They develop in landscape locations that are favourable for water concentration. The area of each “mallín” is usually limited to a few, tens, or hundreds of hectares at most, but independently of their size, they present high variability in their internal physiographic characteristics. These are reflected on the vegetation distribution that basically responds to the space and time water distribution in the “mallín”, both at the surface as well as across the soil profile.We analyze the internal variability of a “mallín type” and present a conceptual map that illustrates the functional relationships established between four basic elements: geomorphology, hydrology, soils and vegetation, whose interrelationships allowed the differentiation of various situations, which may correspond both to different “mallines” and to subunits within the same “mallín”. 相似文献
14.
土壤是植物生长的重要基质,是矿山生态修复成败的关键。针对大多数矿山生态修复所面临缺少土壤的现状和土壤漫长的地质成土过程的现实,试图在阐述自然地质成土原理的基础上,探讨矿山生态修复中的地质成土(简称矿山地质成土)的概念与方法。自然地质成土是地质大循环和生物小循环历经漫长时期将“岩石”变成“土壤”的过程,其中风化、黏化、有机质积聚以及元素的交换和迁移是重要的自然地质成土过程。矿山地质成土是指仿自然地质成土过程,通过筛选矿区可利用的成土母质或土壤材料,采用物理、化学和生物措施促进土壤快速发育和熟化并在短期内形成期望土壤功能、达到自我可持续发育状态的过程,其实质为人工造土。方法包含矿山地质成土的需求分析、成土材料的筛选、土壤材料的组配和生物熟化4步骤,还阐述了矿山地质成土与矿山复垦土壤重构的关系。以内蒙古某露天煤矿生态修复为例,详细讨论基于原始地层材料的露天矿表土的矿山地质成土过程,筛选出原始第3层土壤作为新表土的最优土壤材料组配与生物熟化方法;以矿山固体废弃物为土壤材料,介绍利用自然地质成土原理所构造的煤基生物土的方法;同时对黄河泥沙基矿山地质成土在西部矿区生态修复中的应用给予了展望。 相似文献
15.
Limitation of using heat as a groundwater tracer to define aquifer properties: experiment in a large tank model 总被引：2，自引：0，他引：2
The implementation of the EU-Water Framework Directive (WFD) might also be considered an approach for the implementation of Integrated Water Resources Management in Europe. The WFD outlines the ambitious goal of attaining “good status” for Europe’s rivers, lakes, groundwater bodies and coastal waters by 2015 in accordance with clearly defined time lines and legally binding programmes of measures. EU member states submitted their WFD river basin management plans to the European Commission in March 2010. Almost all member states accomplished the formal implementation, but nations like Germany are far from achieving the “good status”. For Germany, exemptions have been claimed for 82 % of all surface water bodies and for 36 % of all groundwater bodies. According to the identified significant pressures and impacts, the German Federal States, the Federal government and the European Union will have to significantly increase the coordination and coherence of the policies in the field of agriculture, energy generation, transport (shipping) and production or use of chemicals. The next generation of river basin management plans may be used for the harmonisation of these topics and extend to the polluter-specific characterization of water body pressures and impacts, structures and methods of monitoring, allowing the differentiation of multiple stressors, the designation of heavily modified water bodies and the determination of good ecological potential, exemptions and their justification, coherent transregional management objectives and reporting issues. The present study focuses on the assessment of the status of German water bodies, the achievement of environmental objectives and the necessary measures required to meet the goals. 相似文献
16.
This study assesses a simple sediment source tracing method using major- (Al, Ca, Fe, K, Mg, Mn, Na, P, Si, Ti) and trace-element (Ba, Be, Ce, Co, Cr, Mo, Nd, Pb, Sr, Th, V, Y, Zn) signatures of stream suspended particulate matter (SPM), bed sediments and soils in a small agricultural catchment in NE Scotland. Whilst most erosion studies characterise the large amounts of material mobilised at the highest flows, this study aimed to assess properties of sediments during moderate to low flow periods. These occur more frequent than intense storms and are important in linking stream sediments, near-channel sources and aquatic ecosystem impacts. Data were transformed by multivariate statistical methods to compare elemental signatures of SPM (ranging from 3 to 53 mg L−1 in the stream) and stream bed sediments with a limited number of near-channel source soils. Increased concentrations of Ce, Nd, Th and Y in subsoils contributed to the ability to discriminate between surface fieldslope and stream bank erosion sources. Stream bed sediments showed close matches with compositions of stream bank and arable surface soils, but signatures of SPM differed greatly from any of the sources. Large concentrations of Cr, Pb and Zn in SPM, particularly during summer (677, 177 and 661 mg kg−1, respectively) exceeded water quality standards and were linked to an accumulation of trace elements associated with biological material. The potential for within-stream alteration of SPM in relation to erosion sources was confirmed by changes in the nature of the SPM organic matter observed by IR spectroscopy. Thus the potential is shown for multi-element signatures to give information on catchment sediment sources to aid land management decisions, given careful consideration of the effects of in-stream alteration of eroded material. However, this combined information may be beneficial to process understanding linking land use and stream ecosystems at critical ecological periods. 相似文献
17.
Rambabu Singh Tajdarul H. Syed Suresh Kumar Manoj Kumar A. S. Venkatesh 《Arabian Journal of Geosciences》2017,10(14):318
The present study assesses the impact of coal mining on surface and groundwater resources of Korba Coalfield, Central India. Accordingly, water samples collected from various sources are analyzed for major ions, trace elements, and other mine effluent parameters. Results show that the groundwater samples are slightly acidic, whereas river water and mine water samples are mildly alkaline. Elevated concentrations of Ca2+, Na+, HCO3 ?, and SO4 2? alongside the molar ratios (Ca2++Mg2+)/(SO4 2?+HCO3 ?) <1 and Na+/Cl? >1 suggest that silicate weathering (water-rock interaction) coupled with ion exchange are dominant solute acquisition processes controlling the chemistry of groundwater in the study area. The overall hydrogeochemistry of the area is dominated by two major hydrogeochemical facies (i.e., Ca–Cl–SO4 and Ca–HCO3). Analysis of groundwater and river water quality index (GRWQI) elucidates that majority (82%) of samples are of “excellent” to “good” category, and the remaining 12% are of “poor” quality. Similarly, the effluent water quality index (EWQI) indicates that 6 out of 8 samples belong to excellent quality. Concentration of trace element constituents such as As, Zn, Cu, Cr, and Cd is found to be well within the stipulated limits for potable use, except for Fe, Mn, and Pb. Suitability of water samples for irrigation purpose, established using standard tools like Wilcox and USSL diagrams, reveal “excellent to permissible” category for majority of the samples. The present study also substantiates the effectiveness of the measures implemented for the treatment of mine effluent water. 相似文献
18.
Liu Yang Feng Yongneng Xu Mo Zhang Yunhui Long Haitao Zhu Haiming 《Natural Hazards》2019,98(2):343-377
Tunnel water inrush disaster is a serious problem in karst tunnel construction and occurs extensively in southwestern China. To prevent water inrush, hydraulic lining has been utilized extensively in karst tunnel construction. The failure of the hydraulic lining in the Tongxi tunnel is an example of a typical failure case that has yet to be fully analyzed. In this paper, the failure of the waterproof liner was studied by theoretical and numerical methods. By field investigation, the failure of the tunnel lining was attributed to a high hydraulic pressure head converging in the large karst caves behind the lining. The corresponding mechanical model can be simplified as a “karst cave water pressure” model. The key to the mechanical model was to determine the water pressure of the karst caves produced by the lining. The variation in water pressure was directly related to the cave’ reservoir volume, catchment flow and catchment time. Thus, volume calculation formulas for two types of karst caves (strike and oblique caves) in the studied tunnel were constructed based on the engineering geological conditions. Considering the precipitation, the flow rate in the karst caves was regarded as nearly constant during the catchment period. Hence, reservoir volumes during different periods can be calculated and converted to the stress boundary conditions of the lining. Then, the mechanical response of the tunnel under different water levels was calculated by numerical simulation. Combining the field investigation and monitoring data, the tunnel lining failure was mainly believed to be triggered by hydraulic fracturing failure due to a high-pressure head. Finally, prevention measures were proposed based on the results of this study.
相似文献19.
地质历史时期长江入海沉积物的来源和组成特征是探讨东亚边缘海地区沉积物“从源到汇”过程的核心问题之一。崇明岛H12钻孔沉积物元素与同位素地球化学分析揭示,Nd同位素、Eu异常、Cr/Th、Sc/Th等指标在1858—1906年间明显波动,波动的年份与文献记载的洪水事件发生时间基本一致;而在1906年之后沉积物中以上各地球化学指标趋于稳定。结合长江不同支流的沉积地球化学组成特征,运用物源混合模型进行判别,结果显示过去150年来长江入海沉积物主要来自上游支流及汉江,不同支流的洪水信号可以通过入海沉积物通量和化学组成来提取。20世纪以来H12钻孔沉积的各物源指标波动明显减小,推测与崇明岛当地的人类活动逐渐增强有关,防护堤、海塘等工程修建改变了长江入海沉积物在崇明岛的沉积方式,使得洪水时期沉积物无法在岛上淤积,因而钻孔记录中很难再发现洪水事件信号,沉积地球化学物源指标趋于稳定。 相似文献
20.
J. I. S. Zonneveld Dr. 《GeoJournal》1983,7(2):121-129
Modern geography is based on ecological thinking. In this paper some geoecological notions are discussed: the scales and levels regarding spatial magnitude and complexity, the “hierarchy” of landscape units and espcially the scale of time and the concept of the supper-imposing “stamps”. This last mentioned concept is very important in relation to the problem regarding regionalization and its possibilities. Three “stamps” are recognized: 1. the substrate, 2. the climatic conditions, 3. the human (noötic) influence. Holistic regionalization in which all elements (including the human influences) are telling to full advantage, is unsatisfactory. 相似文献