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1.
In the north of France, high registers of nickel are sometimes recorded within the chalk aquifer. In a confined context, the presence of pyrite in the covering clays or in the marcasite nodules encrusted in the clay may constitute a natural source of trace metals. With an objective of sanitary control, the limits of chemical contents regulating the quality of water destined for human consumption have been lowered by the European Framework Directive in the field of water policy (2000/60/EC). As a result, nickel limits have been reduced from 50 to 20 μg/l. The analyses, carried out on three water catchment fields in our area of study, were centred on variable parameters (Eh, O2(d), pH, Conductivity, T°), major elements (SO4, NO3) and metals (Fe, Ni, Mn, Co). The acquired data enabled us to identify from one hand, the conditions which are presented within the site, special thanks to the evolution of nitrate and iron contents and on the other hand, the natural origin (geological) of nickel for two of the three sites studied based essentially on the evaluation of the Nickel/Cobalt ratio. Thus, on the first site, the evolution of nickel content and nitrate content showed the influence of the phenomenon of denitrification on the re-mobilisation of the nickel. Whereas on the second site, a high variation of total iron content and oxygen dissolved in solution highlighted a particular phenomenon of oxidation of the pyrite through molecular oxygen. Finally, the correlation with the sulphates clearly showed behaviour of the nickel, once released, that was entirely dependent on the phenomenon of adsorption on the iron and manganese hydroxides.  相似文献   
2.
Earthquake hazard maps for Syria are presented in this paper. The Peak Ground Acceleration (PGA) and the Modified Mercalli Intensity (MMI) on bedrock, both with 90% probability of not being exceeded during a life time of 50, 100 and 200 years, respectively are developed. The probabilistic PGA and MMI values are evaluated assuming linear sources (faults) as potential sources of future earthquakes. A new attenuation relationship for this region is developed. Ten distinctive faults of potential earthquakes are identified in and around Syria. The pertinent parameters of each fault, such as theb-parameter in the Gutenberg-Richter formula, the annual rate 4 and the upper bound magnitudem 1 are determined from two sets of seismic data: the historical earthquakes and the instrumentally recorded earthquake data (AD 1900–1992). The seismic hazard maps developed are intended for preliminary analysis of new designs and seismic check of existing civil engineering structures.  相似文献   
3.
The study deals with the effect of metal toxicity (aluminum, chromium and combination of both the metals) on seed germination, root length, shoot length, seedling length and dry biomass of Vigna radiata and V. sinensis. Chromium adversely affected the seedling by significantly reducing the growth whereas aluminum did not show such effect in both the species. Percentage of germination was good in both the species at different concentration of treatment (aluminum, chromium and combined treatment). Shoot length was also not much affected in V. sinensis as it was greatly inhibited in V. radiata. Both the species showed the purpling of stem. Dry biomass of V. radiata showed positive effect than V. sinensis. However, dry biomass decreased to a lesser extent when treated with aluminum, chromium and combined treatment as compared to control.  相似文献   
4.
The Rharb basin is located in northwestern Morocco. It is a part of one of the most important hydrogeological basins of Morocco, and extends over some 4000 km2. The nature of its Plio-Quaternary sedimentary fill and its structural and palaeoenvironmental contexts are reflected by great variations in aerial and temporal facies distribution. This distribution, in turn, is a direct cause of the observed complexity in the geometry of potentially water-bearing beds. In the present work, we present an image of potential new hydrogeological reservoirs and define new structures that partially explain their architecture. To cite this article: M. Kili et al., C. R. Geoscience 338 (2006).  相似文献   
5.
The northern edge of the Central Rif (Morocco) is subject to numerous landslides where mechanisms do not correspond to the classical models used by geomechanics specialists. It is necessary to adopt a multidisciplinary approach that combines geomorphology, geology, hydrogeology, and geotechnics in order to understand how such slope failures are generated, especially in a region with a heterogeneous structure characterised by significant lithological differences, severe fracturing, and thrust sheets where tectonic contacts play a major role in groundwater circulation. This report shows that these failures are essentially controlled by the tectonic contact separating the Tisirene and Chouamat thrust sheets and by subsurface hydrodynamic conditions. A model of spatial and temporal variations in the factor of safety is proposed.  相似文献   
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The prediction of useful lifetime of a dam is estimated through accurate estimate of river sediments which mostly depend on sediment rating curve. Over the past decades, various methods have been developed by investigators. With respect to the importance of this issue, in the present study, the best discharge-sediment relationship for Jelogir hydrometric station located at the upstream of Karkheh reservoir dam is presented. In the first step, sediment rating curves in annual, seasonal, monthly, wet and dry, and middle of the classes linear ways and applying 3 correction coefficients that include Smearing, FAO, and QMILE were obtained; then, their performance was evaluated. Comparison of these results with data obtained from hydrographical operation of Karkheh dam reservoir showed that the optimal equation of discharge-sediment at this hydrometric station follows annual linear sediment rating curve with QMILE correction coefficient. According to the results, annual method has estimated sediment volume less than the actual volume, about 98.7% of the actual sediment, while other evaluated methods have showed sediment volume more than the actual one, and among correction coefficients, the application of QMILE correction coefficient is more reasonable than other coefficients.  相似文献   
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