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1.
Environmental degradation and other socio-economic problems are too often discerned in contemporary pastoral systems in the wake of global economic change. This paper identifies cases where pastoral people respond to external pressures and opportunities in positive ways and adapt to changes. We hope that by doing this a framework of pastoral adaptations can be developed. The first part of this paper focuses on impacts of global economic change, which are mostly negative in nature. Through an extensive literature search in geography, anthropology, range management, and development field, the second part introduces cases that we categorize as positive adaptations. 相似文献
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Samia Khadhar Dhouha Achour Anis Chekirben Rim Chawachi Ammar Mlayah Abdelkrim Charef 《Arabian Journal of Geosciences》2018,11(17):522
El Bey river, which drains 60% of the pollutant load of several urban cities in the northeast of Tunisia, provides a good example of the transfer of organic and metallic pollutants that result from industrial and urban activity, and can be used to show how these charges are transported and discharged into the Gulf of Tunis. Persistent organic pollutants (PAH and PCB) in dissolved, particulate matter, bed sediments, and three wastewater effluents in El Bey watershed were analyzed. PAH (∑14PAHs) concentration ranged from 0.248 to 9.955 mg L?1 and from 0.836 to 28.539 mg L?1 in dissolved and particulate fraction respectively. The particulate/dissolved partition coefficient value (Kd) was less than one which confirmed the affinity of PAH to be adsorbed. In sediment, the high-molecular weight PAHs were found principally with percentage between 50 and 100% witch present 239.99 to 5362.19 μg kg?1, which is relatively higher in comparison with other estuaries river. Contrary to PAH patterns, PCB were bound to dissolve fraction. Kd (PCB) value (Kd?>?1) reflected this affinity which is related to environment energy. The spatial distribution and profile of analyzed organic pollutants confirmed the direct impact of wastewater effluent on the organic pollution level in three compartment of El Bey watershed and his profiles suggested different transport patterns. 相似文献
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Hassen Ouelhazi Fethi Lachaal Abdelkrim Charef Bilel Challouf Habib Chaieb Faten Jarraya Horriche 《Arabian Journal of Geosciences》2014,7(10):4407-4421
Korba aquifer is one of the most typical examples of overexploited coastal aquifer in the Mediterranean countries. In fact, from 1985, a considerable piezometric level drop, water salinization, and seawater intrusion were registered in the aquifer. In December 2008, Tunisian authorities initiated a general plan to groundwater management in order to augment groundwater resources, restore the piezometric levels, and improve water quality. The plan consists of artificial recharge of groundwater used treated wastewater through three infiltration basins. During the first 4 years (from December 2008 to December 2012), 1.41 Mm3 of treated wastewater was injected to the Korba aquifer. This study presents a hydrogeological assessment of groundwater evolution during the recharge processes. In this study, 32 piezometric and chemical surveys of 70 piezometers and observed wells are used to present hydrogeological investigation and water quality evolution of wastewater reuse through artificial recharge in Korba coastal aquifer. The piezometric evolution maps are used to specify the positive effect in groundwater level that exceeding 1.5 m in some regions. The interpretation of salinity evolution maps are used to indicate the improving of groundwater quality. 相似文献
4.
Making use of the homogenization method for periodic media, developed in the context of elastoplasticity, a simplified constitutive law is proposed for a stone column-reinforced soil, regarded as a homogeneous but anisotropic medium. The closed-form expressions derived for such a constitutive law allow for its implementation into a f.e.m-based numerical procedure. The computational code so obtained is then applied to simulating the response of a foundation soil reinforced by a group of floating columns, expressed in terms of load–settlement curves drawn up to the ultimate bearing capacity. 相似文献
5.
Michel Villeneuve Hervé Bellon Abdelkrim El Archi Mohamed Sahabi Jean-Pierre Rehault Jean-Louis Olivet Abdel M. Aghzer 《Comptes Rendus Geoscience》2006,338(5):359-367
The Adrar Souttouf belt (Western Sahara) lies in the northern part of the Mauritanide belt and was considered as a part of the Hercynian Mauritanian-Appalachian belt. Recently the presence of a Panafrican protolith (595 Ma) was evidenced by the age of inherited zircons from an eclogitic unit and led to consider complex Panafrican events included in the Hercynian belt, as in the central and southern Mauritanide belt. Our new field survey completed by ten KAr dating (whole rocks and separate minerals) confirmed that multiphased Panafrican formations outcrop within the center of the Adrar Souttouf massif. Diverse events ranged from ca. 1000 to 500 Ma, some of them being indicative of an oceanic type environment and metamorphism. The 1000 Ma metamorphic event is recorded for the first time in the West African craton. A large Hercynian remobilisation is also evidenced. To cite this article: M. Villeneuve et al., C. R. Geoscience 338 (2006). 相似文献
6.
Samia Khadhar Ammar Mlayah Anis Chekirben Abdelkrim Charef Malika Methammam Shabou Nouha 《水文科学杂志》2013,58(8):1803-1812
RésuméL’Oued El Bey, qui draine 60% de la charge polluante hydrique de plusieurs agglomérations urbaines du Nord-Est de la Tunisie, est un exemple représentatif du transfert des métaux lourds résultant de l’activité industrielle et urbaine. Il fournit une indication sur le devenir et la répartition des métaux lourds dans le Golfe de Tunis. Dans la fraction dissoute, Cd, Pb, Co et Hg ne sont pas détectés mais Zn varie entre 0,01 et 0,07 μg/L. Les concentrations du Mn, Zn, As, Ni, Pb, Cu et du Cd sont très élevées dans la fraction particulaire par rapport à la fraction dissoute, avec un coefficient de partage Kd de l’ordre de 106, ainsi que dans les sédiments du lit de l’oued pour Pb et Zn. La pollution par les métaux la plus élevé de l’Oued El Bey a été trouvée pour Zn, Pb et Cu: les concentrations variaient respectivement entre 1698,9 et 14575, de 0 à 2153,7 et de 0 à 3431,8 μg/g. La variation spatiale des teneurs en métaux lourds confirme l’effet des eaux usées rejetées dans l’Oued El Bey. Les teneurs de ces métaux lourds dans les trois phases dissoute, particulaire (MES) et sédiments confirment que la MES constitue le vecteur de transport principal via la Sebkha Soliman vers le golfe. L’examen des rapports des différents éléments (Pb, Cu et Cd) par rapport au Zn dans les sédiments de l’oued montre une augmentation au niveau de la confluence de l’Oued El Bey et de son affluent l’Oued El Meleh, ce qui signifie que les apports sédimentaires de cet affluent contrôlent la signatutue chimique des sédiments de l’Oued El Bey.Editeur Z.W. Kundzewicz; Editeur associé B. TouaibiaCitation Khadhar, S., Mlayah, A., Chekirben, A., Charef, A., Methammam, M., Nouha, S., et Khemais, Z., 2013. Bassin versant Oued El Bey: vecteur de transport de la pollution métallique vers le Golfe de Tunis (Tunisie). Hydrological Sciences Journal, 58 (8), 1803–1812. 相似文献
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8.
Evaluation of climate change effects in a coastal aquifer in Morocco using a density-dependent numerical model 总被引：2，自引：1，他引：1
Júlio Ferreira Carneiro Mimoun Boughriba António Correia Yassine Zarhloule Abdelkrim Rimi Boubker El Houadi 《Environmental Earth Sciences》2010,61(2):241-252
A density-dependent numerical groundwater model was applied to study the climate change impact in a shallow aquifer in the Mediterranean coast of Morocco, the Saïdia aquifer. The stresses imposed to the model were derived from the IPCC emission scenarios and included recharge variation and sea level rise. The main effect of the climate change in the Saïdia aquifer will be a decrease in renewable resources, which in the worst-case scenario may decrease to 50–60% of present-day values, due to the decline in recharge and to a reduced inflow from the adjacent Triffa aquifer. The water quality will be affected mostly in the area immediately adjacent to the seashore, where salinity may increase up to 30 g/l. Localised areas may see a decrease in salinity due to the induced freshwater recharge from Oued Moulouya River and diminished inflow from high-salinity springs. 相似文献
9.
Merzouk Ouyed Mouloud Idres Amar Bourmatte Mohamed Salah Boughacha Sadek Samai Abdelkrim Yelles Abderrahmene Haned Chafik Aidi 《Journal of Seismology》2011,15(2):173-189
In order to try to identify the seismogenic sources in the epicentral area, we interpreted data collected from gravity and
aftershocks in the eastern part of the Mitidja basin after the occurrence of the 21 May 2003 Boumerdes earthquake (Mw = 6.8).
The residual gravity anomaly and the horizontal gradient maps revealed the basement shape and density discontinuities. A seismotectonic
model obtained from the aftershocks distribution and gravity data is proposed. This model highlights three active faults:
one offshore and two onshore. The offshore reverse fault striking NE-SW, parallel to the coast, is consistent with the USGS
focal mechanism of the main event, which is assumed to have the most moment release. The two onshore dipping blind active
faults are postulated at crossing angles near the SW tip of the main fault. The interpretation is based mainly on the re-location
and distribution of aftershocks, and their focal solutions. It is also supported by the basin structures obtained from the
inversion and interpretation of residual gravity anomalies, as well as by additional compiled information such as the pattern
of coastal co-seismic uplift. This configuration puts forward the failure mode complexity during the main shock. The topography
of the basement obtained from 3D gravity inversion shows that all the onshore located aftershocks occurred in the basement,
and the area between the two onshore faults rose as a consequence of their sliding. 相似文献
10.
Mariem Trifi Mohja Dermech Charef Abdelkrim Rim Azouzi Bilel Hjiri 《Arabian Journal of Geosciences》2018,11(12):328
The wall rocks of Sidi Driss mineralization contain continental molassic deposits: lacustrine limestones, ferruginous fragments, Ed Diss unit and Numidian unit fragments, rhyodacitic fragments, pyroclasts, and gneissic fragments. The ore is composed of pyrite, marcasite, sphalerite, galena, barite, celestite, siderite, calcite, and iron oxide-hydroxides. The abandoned wastes in Sidi Driss-Tamra district contain marcasite, galena, goethite, jarosite, anglesite, anhydrite, bassanite, and gypsum. It is very important to assess the hazards and risks that this material type poses to public health and the environment. However, evaluation of a part of toxic elements always poses problems since the associated matrix, the close relationships between some minerals, the grain sizes and their forms (oolites, compact collomorphes aggregate), the oxidation degree of metals, the chemical composition, and trace elements make it difficult to extract mobile metals from complex Sidi Driss tailings and minerals found in these acidic wastes. Nevertheless, there is no universal method that can systematically evaluate metal bioavailability. And the use of proposed sequential extraction procedures for sediments with simple mineralogical composition did not yield any reproducible results for this type of acid mine drainage sediments. Consequently, the methods of controlling and mitigating the risks of hazardous materials should be considered. Many extraction procedures have been applied to better evaluate the mobility of hazardous materials (metals), the characterization of their degree of toxicity, and their chemical behavior in these complex mine tailings. Reproducible results were obtained with lab-scale washing of sediments using distilled water, CaCl2 and Na2-EDTA solutions, and BCR sequential extraction. The results showed that the BCR extraction approach was the most efficient procedure for these types of wastes. The extraction with distilled water is recommended for identification of the total quantity of mobile Cr and Fe. 相似文献