Charakterystyka wód gruntowych przeznaczonych do zasilania miasta Khenchela (wschodnia Algeria) w wodę pitną

In spite of the abundance of water resources in the watershed of Khenchela region, the strong urban growth and the expansion of agricultural land resulted in a considerable increase in water needs. This fact exposed groundwater and surface vulnerability to an overlooked growing pollution. In this vein, this study aims to determine the global quality of groundwater oriented to drinking water supply in Khenchela city. It focuses particularly on looking for minerals, nutrients and salt concentration and to assess their spatial and temporal variability. This area has been the subject of several previous studies due to the importance of its watershed (hydrology, geology, geomorphology, bacteriology...). The dosage of the considered parameters revealed vulnerability of water of the North and the North Western part of the watershed to the strong mineralization and excess of organic minerals. This requires in the short term an obligation to treat this water before distribution. A permanent monitoring and the use of other evaluation means for quality protection of this vulnerable resource have been taken into account.Mimo obfitości zasobów wodnych w zlewni regionu Khenchela, intensywna urbanizacja i powiększanie obszaru gruntów rolniczych znacząco zwiększyło zapotrzebowanie na wodę. Mając to na uwadze, podjęto badania nad jakością wód gruntowych przeznaczonych do zasilania miasta Khenchela w wodę pitną. Skupiono się na stężeniu związków mineralnych, pierwiastków biogennych i soli oraz na ich przestrzennej i czasowej zmienności. Ze względu na znaczenie zlewni obszar badań był przedmiotem kilku wcześniejszych studiów nad hydrologią, geologią, geomorfologią i bakteriologią. Mierzone parametry ujawniły podatność wód północnej i północnozachodniej części zlewni na mineralizację i nadmiar substancji mineralnych. Wymaga to uzdatniania wody przed jej dystrybucją. Rozważono także stały monitoring i inne metody oceny w celu ochrony jakości tych wrażliwych zasobów

Caractérisation de la qualité des eaux de I' oued Kebir Quest (Nord Est algérien)

La vulnérabilité des eaux souterraines et de surface du côtier constantinois centre (région de Skikda) et plus particulièrement le bassin versant du Kebir Ouest (côté Est), est liée au contexte industriel, agricole et urbain.Malgré une relative richesse des ressources en eau, la forte croissance économique, la concentration urbaine accélérée et la modernisation de l'agriculture ont entraine, non seulement, un accroissement considérable des besoins en eau mais aussi un fort degré de pollution. Cette pollution s'accentue en fonction d'un certain nombre de facteurs, tels que l'emplacement du cours d'eau par rapport aux rejets des eaux usées et l'activité agricole.Plusieurs facteurs conditionnent la progression de cette pollution, comme les concentrations des polluants dans les eaux usées, la nature des sols et la lithologie. La présente étude vise à déterminer la qualité globale de l’eau de l'oued Kebir Ouest et de ses principaux affluents et à évaluer la variabilité spatiale et temporelle des polluants. Les résultats obtenus ont montre l'état critique dans lequel se trouvent les eaux, vis à vis de la matière organique à l'amont de l'oued, les fortes concentrations en certains métaux lourds, principalement le mercure, et finalement la faible salinité des eaux vers l'amont du bassin versant.Mots clés: Kebir Ouest - Skikda - Bassin versant - Qualité - Pollution - Métaux lourds. The vulnerability of groundwater and surface of the coastal center of Constantine (Skikda region) and more precisely the watershed of West Kebir is function of the industrial agricultural and urban contexts.Despite a relative capital of water resources, high economic growth accompanied by high industrialization, urban concentration and accelerated modernization of agriculture, have led to significant increase of water requirements and consequently a high degree of pollution which depends on a number of factors such as location of streams in relation to discharges of sewage and agricultural activity.Several factors influence the progression of this pollution includes the concentrations of pollutants in wastewater, soil type, and lithology, permeability of the aquifer and the depth of the water. This study aims to determine the overall quality of water from the Kebir West River and its major tributaries and to assess the spatial and temporal variability in dry weather and wet weather.Keywords: West Kebir - Skikda - Watershed - Quality - Pollution - Resource alteration

Perfluorosulfonate-polyether based single ion conductors

International audienceNew salts with monomer functionality and bearing a perfluorosulfonate group have been synthesized. These salts contain one or two carbon double bonds and thus can be incorporated into crosslinked solvating ionomers. Another family possesses epoxy rings and can be copolymerized with ethylene oxide. The results, in terms of ionic conductivities and thermal behavior are reported for these singlecation conductor polymer electrolytes. The conductivity values of these materials are markedly higher than those previously reported for other t+ = 1 materials. The loss in conductivity, as compared to the untethered salt complexes, corresponds approximately to that attributed to the anionic conductivity. Alkali metals rank in the order σK+ > σna+ > σLi+

Distribution of Medicago species and their microsymbionts in a saline region of Algeria

We studied symbiosis of Medicago ciliaris and Medicago polymorpha, two legumes of forage and ecological importance in Algeria, especially in saline soil regions. We report the spatial distribution of the two species and their microsymbionts along salinity gradient transects in the Sebkha of Misserghin (Algeria, North Africa). Seeds and root nodules were sampled from 10 sites. Twenty-seven rhizobial strains were isolated from root nodules and characterized as fast-growers and slime-producers on yeast mannitol agar. By partial sequencing of the gene coding for the 16 S ribosomal RNA, they were found to be affiliated to Rhizobium, Sinorhizobium, and Agrobacterium but several strains had sequences with separate positions. Interestingly one of these was further assigned to Phyllobacterium. Opposite to rhizobia, the distribution of the two Medicago species varied along the salinity gradient, M. ciliaris being dominant in the low NaCl concentration zones and M. polymorpha dominant in the most saline zones. Tolerance to salinity, of both bacterial and plant partners, was studied under laboratory conditions, showing that plants are susceptible to NaCl concentrations of 50mM, 15-fold lower than that of their associated rhizobia (800mM)