Groundwater of Egypt: “an environmental overview”

Although Egypt has the great Nile River, which is the main supply of water, Egypt’s water is limited to 55.5 billion m³ per annum. Owing to the rapid growth of the population and the increasing consumption of water in agriculture, industry, domestic use, etc., it is expected that Egypt will rely to some extent on groundwater to develop the new projects such as Tushka in Upper Egypt and East Oweinat. Issues related to groundwater in Egypt are identified with the common geological features associated with formation of the aquifers and demonstrating the location of the main resources of groundwater, followed by the main objective of this paper, which is addressing the environmental issues related to groundwater in Egypt. Several studies have been reviewed and personal communication made with the authorities to introduce this work and provide an overview of the groundwater quality problems in Egypt with examples from different parts of the country.     

Isotopic Stratification and Its Implications in Groundwater of Northern China

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Effect of Groundwater Radiolysis on the Wall—rock Alteration of Uranium Ore Deposits

Reported for the first time in this paper are the results of simulating experiments on the γ-irradiation-induced oxidation of Fe^2 under the physicochemical conditions(T=200℃，P=50MPa,Eh=-0.1V,pH=7.2)simial to those under which moderate-low temperature hydrothermal uranium deposits are formed.Evdence shows that the effect of groundwater radiolysis seems to be the major mechanism of wall-rock alteration(hematitizaton)of hydrothermal uranium deposits.Moreover,adiscussion was made of possible effects of radiolysis of the water-rock system on wall-rock alterations including argillization and decoloration of uranium ore deposits on the basis of the experimental results.     

An Analysis of Groundwater in Sinjar Plain (Northwest of Iraq) Using WQI Model

INTRODUCTlONGroundwater is very important in arid and semi--arid areasand in areas located far away from sources of surface water. Itdoes not contain suspended materials, organic materials andbacteria (as long as it does not get polluted from othersources), but it mostIy contains mineraI and chemicaI com-pounds with identified quantities, depending on the type ofrocks presented in the area.The importance of groundwater relies on its quantity,avai1ability and how to substitute its used amo…     

Groundwater–river interaction and management in the context of inter-basin transfers

This study is focused on the management of coupled groundwater–river interaction (GRI) in the context of inter-basin transfers. The semi-coupled models, HEC-RAS and MODFLOW, were utilized in this study to replicate the River Tees experiment that had been conducted in 1976. Then the ‘surrogate’ models were applied to two “what if” scenarios in order to understand and manage GRI behavior and the nature of the reservoir control system. The results on the River Tees showed that the total temporary bankside storage volume was up to 17.5 % of the total reservoir release, given about 22 h of travel time. In addition, zones 4 and 5 of the river model with significant alluvium deposits were the best storage sites with values of 4.5 and 6.7 % of the total reservoir release, respectively, estimated as temporary losses. The final direct runoff received downstream at broken scar was about 95 % of the Cow Green total reservoir release. Furthermore, the closure rate proved to be vital to compute the effective return flow in respect of this study area. Finally, with careful reservoir and groundwater management, the River Tees proved to be an ideal natural aqueduct for inter-basin transfers when used as part of a major regional water resources scheme.     

The Characteristics of Fluorine in the Groundwater of North China and the Significance of Fluorite-Water Interaction to Fluorine Transportation

This paper approaches the transportation of fluorine in the groundwater ofepigene Quarternary aquifer by calculation and laboratory studies.The conclusionthat the enrichment and saturation abilities of fluorite are related to the transpor-tation of fluorine in groundwater is reached.They would be conducive to findingthe cause of regional fluorine distribution in the groundwater of North China.     

Hydrogeochemistry and Origin of Thermal Groundwater in Bedrock Aquifers in Tianjin, China

INTRODUCTIONThermalgroundwaterisfoundtohaveoccurredinthebedrockcarbonateaquifersofLowerPaleozoicandMeso toNeo ProterozoicErathemsnearTianjin ,China .Thebedrockaquifersexistinthelayersbetweenabout 10 0 0mandmorethan 4 0 0 0mbelowthelandsurface .Thethermalwaterhasbeensuccessfullydevelopedoverthepast2 0yearstoprovideasourceofhotwaterforavarietyofresidentialandindustri alpurposes.Geothermalwellstappingtheaquifersarecapa bleofproducingcommercialquantitiesofhotwaterwiththetemperaturesranging…     

Deformation and Compression Behaviour of a Cement–Bentonite Slurry for Groundwater Control Applications

Cement bentonite (CB) barriers are self-supporting, low permeability, structures used to retard groundwater flow and as such strength and hydraulic conductivity parameters are often stipulated when developing the mixtures. This paper reports an investigation into the deformation and compression behaviour of a CB containing ground granulated blastfurnace slag using the unconfined compressive strength apparatus, triaxial (undrained, unconsolidated) and oedometer. Samples were also exposed to drying and rewetting to investigate possible response to changes in environmental conditions. Cracking was observed prior to peak stress suggesting that the hydraulic conductivity of a barrier may be adversely affected before the shear strength is reached in undrained conditions. The compression response of CB indicates the presence of a threshold stress; once exceeded the magnitude of settlements are significantly greater than those encountered below this threshold. If a barrier experiences localised changes in loading conditions then there is the potential for damage from induced differential settlements; thus it is recommended that the threshold stress should also be considered at the design stage in addition to strength and hydraulic conductivity requirements. The response of the material exposed to drying-rewetting was unexpected and requires further investigation to determine how a barrier will respond to changing environmental conditions.     

The Background Features and Formation of Chemical Elements of Groundwater in the Region of the Middle and Lower Reaches of the Yangtze River

The paper deals with the background features, formation and distribution of the chemical el-ements K, Na, Ca, Mg, Si, Fe, Mn, Cr, Ni,V, Co, Ti, Mo, Cu, Pb, Zn, As, Hg, Cd, Be, Li, Sr, B,F, Cl, Br and I in the groundwater in the region of the middle and lower reaches of the YangtzeRiver and their relations to the composition of the water-bearing media, properties of the overly-ing rocks and soils, redox environment, and groundwater flow condition, mineralization and pHof groundwater.     

Groundwater vulnerability map of the Chrzanów karst-fissured Triassic aquifer (Poland)

A map shows intrinsic vulnerability to pollution of the Chrzanów karst-fissured aquifer (273 km²) in the southern part of Poland. This aquifer is intensively drained by numerous intakes and Zn-Pb ore mines. A DRASTIC-type parametric system was applied for groundwater vulnerability evaluation. Vulnerability assessment is based on six factors (depth to groundwater table, lithology of the unsaturated zone, net recharge, hydraulic conductivity of the aquifer, groundwater flow velocity, aquifer thickness). For the final vulnerability map construction at the scale of 1:50,000, a combination of the aquifer simulation model (using MODFLOW) and a geographical information system was applied. Maps of the net recharge, hydraulic conductivity of the aquifer and groundwater flow velocity were derived by aquifer modelling. Based on the vulnerability index (21-182), six relative vulnerability classes were selected. Reliability of the map has been verified.     

Groundwater pollution by arsenic concentration in sedimentary aquifers in the Indo-Gangetic Basin of Nepal

Naturally occurring arsenic （As） in groundwater of sedimentary aquifers has emerged as a global problem, and the Indo-Gangetic Basin of Nepal is no exception. In the sedimentary aquifers of the Indo-Gangetic Basin, arsenic enrichment and mobilization in groundwater by natural processes is considered an issue of major environmental health concern. About 11 million people, 47% of Nepali＇s total population living in the region and approximately 90% of them are relying on groundwater as their major source of drinking water. Moreover, 205555 ha of agricultural land in the basin are irrigated by groundwater through large numbers of deep and shallow irrigation tubewells for extensive cultivation of crops which has lead to creation of other pathways for arsenic ingestion among the people living in the region. It is estimated that around 0.5 million people in the basin are living at risk of arsenic poisoning In addition, some recent research shows the prevalence of dermatosis related to arsenicosis from 1.3% to 5.2 % and the accumulation of arsenic in biological samples like hair and nails much higher than the acceptance level. In these circumstances, the source of the natural arsenic concentration in groundwater of the Indo-Gangetic Basin is quite essential to explore. Therefore, to investigate the source of arsenic and management of arseniferious groundwater used for human consumption and irrigation, along with treatment or avoidance, is clearly an issue of research concern. Present research is carried out to understand the source of natural arsenic and its mobilization in groundwater of the Indo-Gangetic Basin. For this, we have collected bedrock, aquifer sediments and water samples from the study area. Sediment samples were taken from different lithofacies viz. clay, silt, sand and sandy gravels from groundwater aquifer where arsenic concentration is high. Water samples were taken from domestic shallow and deep tubewells in grid pattern. Bedrock samples were collected from source of the aquifer sediment, northern part of the Indo-Gangetic Basin, especially from the Siwalik and Lesser Himalaya. This paper particularly focuses on geology, mineralogy, hydro-geochemistry and sedimentary analysis of the high arsenic affected districts; Rautahat, Sarlahi, Parsa, and Kailali of Nepal.     

Groundwater–wetlands interaction in coastal lagoon of Almería (SE Spain)

Water resources management in coastal wetlands requires the degree of interdependence between groundwater and terrestrial ecosystems to be known. This is especially so in semiarid areas where surface inflows are restricted, marine influence is marked and the evaporation rate is high. Thus, chemistry of surface waters is very variable in the Cerrillos-Punta Entinas wetlands system. Using classical hydrogeochemical tools, the main processes that favor a diversity of water types were described, related to: presence of salt deposits on the lagoon beds, marine origin of the water, and local influence of groundwater. All these factors make it difficult to establish what reference conditions should be used to define “good” water quality of the surface waters—as required by the Water framework directive—and to understand the influence of groundwater on these coastal wetlands. Knowledge about the influence of the different interaction of these factors on the hydrogeochemical dynamics is required for the sustainable management of this protected natural site.     

Isotope Method for Confined Groundwater Recharge of the Lower Reaches of the Heihe River, Inner Mongolia, China

Environmental isotopes have been applied to analyze confined groundwater recharge in the lower reaches of the Heihe River,Inner Mongolia.CFC is regarded as a tracer that determines the date of groundwater,the date being less than 45 a.The confined groundwater within the Gurinai area and Ejin Basin other than the surface water of Heihe River might have originated from precipitation from Qilian Mountain or/and the Tibetan Plateau.The deep confined groundwater overflows into an upper aquifer and emerges into the ground,forming springs and lakes within the low-lying area.The recharge volume is estimated to be around 400 million-cubic meters.     

Groundwater deterioration in Nankou—a suburban area of Beijing: data assessment and remediation scenarios

Since the 1980s, high-nitrate concentration in one of the groundwater sampling wells at the Nankou site, northwest of the Beijing Plain, has become a major concern for the local water authority. In a previous study (Sun et?al. in Environ Earth Sci 64(5):1323?C1333, 2011), a hydrogeological structural model was developed based on the borehole logs of this area and the steady, as well as transient groundwater-flow models, were calibrated using the measured hydraulic heads. In this paper, the potential pollution sources in this area are investigated. The chemical analysis of the groundwater is also presented. The results demonstrate that the most likely pollution source is the untreated wastewater discharge from a nearby fertilizer factory. Furthermore, a mass transport model is developed to reproduce the nitrate transport process in the aquifer at the Nankou site under different pollution sources, i.e., a fertilizer factory, river with wastewater and an agriculture field. The combined effects of the river and agriculture fields present a better understanding of the nitrate transport in the local aquifer. In addition, a pumping scenario is designed to clean up the current nitrate concentration. The pumping rate and the well location are first estimated with 2-D analytical solutions of the type curves method. Then a 3-D numerical model is used to calculate the nitrate-concentration changes after the pumping activities start. In the downstream direction of the regional groundwater flow, three pumping wells are set up for the clean-up strategy. The calculated pumping rate in each well is about 1,500 m³/day. After 1?year, the nitrate concentration in the observation well recedes to 68?mg/l from the initial value of 72.9?mg/l, and it will be lower than the limitation value (20?mg/l) after 5,400 days of groundwater extraction. The data assessment and clean-up scenarios reported in this paper are fundamental for the contaminated aquifer management in the future.     

15 N Isotope Used for Study of Groundwater Nitrogen Pollution in Shijiazhuang City，China

Shijiazhuang City is the capital of Hebei province，China．Groundwater is the major water supply source for living and industry need of the city．Due to arapid increase of population and development of industry and agriculture，aseries of groundwater environmental problems are created．Inthepaper，the situation of groundwater pollution in Shijiazhuang city is reported．Based on the groundwater chemical data and 15 N measurement results both on groundwater and soils，the reason of groundwater nitrate pollution is studied．