Modélisation de la pollution par les nitrates de la nappe de Berrechid, au Maroc

La nappe de Berrechid a toujours suscité un intérêt particulier en tant qu’une source principale d’irrigation et d’alimentation en eau potable dans la région. Cependant, de nombreux indices indiquent une dégradation de la qualité de son eau, contaminée, notamment par les nitrates dont la concentration est excessive. L’analyse de l’eau a montré que, durant l’année 2004, les teneurs en nitrates ont dépassé la valeur admissible (50 mg/L) dans 70% de l’ensemble des puits de contrôle. Ces concentrations élevées mettent en évidence un lessivage d’importantes quantités d’engrais azotés vers les eaux souterraines, auxquelles s’ajoutent la présence d’une décharge non contrôlée et les eaux usées d’origine domestique et industrielle. L’évolution des teneurs en nitrates dans la nappe a été simulée sur une période de 22 ans, de 1993 à 2015, à l’aide des codes numériques MODFLOW et MT3DMS, intégrés dans le logiciel GMS. Les résultats de la modélisation numérique montrent une dégradation continue et globale de la qualité de la nappe par les nitrates, sauf dans la partie sud-est à proximité de la frontière de réalimentation de l’aquifère par le plateau de Settat.Mots-clés : Modélisation numérique, GMS, MODFLOW, MT3DMS, pollution, nitrates, eau souterraine, Berrechi

ULIXES, unravelling and exploiting Mediterranean Sea microbial diversity and ecology for xenobiotics' and pollutants' clean up

The civilizations in the Mediterranean Sea have deeply changed the local environment, especially with the extraction of subsurface oil and gas, their refinery and transportation. Major environmental impacts are affecting all the sides of the basin with actual and potential natural and socio-economic problems. Events like the recent BP\u2019s oil disaster in the Gulf of Mexico would have a tremendous impact on a close basin like the Mediterranean Sea. The recently EU-funded project ULIXES (http://www.ulixes.unimi.it/) aims to unravel, categorize, catalogue, exploit and manage the microbial diversity available in the Mediterranean Sea for addressing bioremediation of polluted marine sites. The rationale of the project is based on the multiple diverse environmental niches of the Mediterranean Sea and the huge range of microorganisms inhabiting therein. Microbial consortia and their ecology, their components or products are used for designing novel pollutant- and site-tailored bioremediation approaches. ULIXES exploits microbial resource mining by the isolation of novel microorganisms as well as by novel advanced \u2018meta-omics\u2019 technologies for solving pollution of three major high priority pollutant classes, petroleum hydrocarbons, chlorinated compounds and heavy metals. A network of twelve European and Southern Mediterranean partners is exploring the microbial diversity and ecology associated to a large set of polluted environmental matrices including seashore sands, lagoons, harbors and deep-sea sediments, oil tanker shipwreck sites, as well as coastal and deep sea natural sites where hydrocarbon seepages occur. The mined collections are exploited for developing novel bioremediation processes to be tested in ex situ and in situ field bioremediation trials

ISSN-2141-226X ©2011 Academic Journals

Study of multi-resistance to heavy metals, antibiotics and some hydrocarbons of bacterial strains isolated from an estuary basi

A comparative study of marine zooplankton communities in the Tangier and M’Diq (Gibraltar strait) regions

This comparative study of mesozooplankton communities in the Tangier (Atlantic) and M’Diq (Mediterranean) regions was carried out in March, May and December 2006 and in May, July and November 2007. In both sectors, the zooplankton is mainly dominated by copepods, which represent 93% in Tangier and 87% in M’Diq, with respectively 85 species in 24 families and 81 divided into 22 families. Spatio-temporal analysis of Copepod specific richness data revealed highest values occurring in both areas during December 2006 and November 2007 with 36 and 30 species respectively. During other seasons, specific richness did not generally exceed 25 species. However, irrespective of area, the composition of the Copepoda population was usually dominated by Paracalanus parvus and Oncaea venusta. In terms of total density, the Atlantic is greater than the Mediterranean sector with a maximum density of 1093 ind.m-3 and 796 ind.m-3, respectively, recorded in July and May, 2007. The Shannon diversity index was calculated and indicated that the Copepod community is more stable and balanced in the Tangier region compared to the M’Diq area, and in 2007 compared to 2006. Moreover, seasonal variation is more marked in the Atlantic than in the Mediterranean area and in both sectors, the autumn season is characterized by a low productivity but high specific diversity

Biogenic nanopalladium based remediation of chlorinated hydrocarbons in marine environments

Biogenic catalysts have been studied over the last 10 years in freshwater and soil environments, but neither their formation nor their application has been explored in marine ecosystems. The objective of this study was to develop a biogenic nanopalladium-based remediation method for reducing chlorinated hydrocarbons from marine environments by employing indigenous marine bacteria. Thirty facultative aerobic marine strains were isolated from two contaminated sites, the Lagoon of Mar Chica, Morocco, and Priolo Gargallo Syracuse, Italy. Eight strains showed concurrent palladium precipitation and biohydrogen production. X-ray diffraction and thin section transmission electron microscopy analysis indicated the presence of metallic Pd nanoparticles of various sizes (5-20 nm) formed either in the cytoplasm, in the periplasmic space, or extracellularly. These biogenic catalysts were used to dechlorinate trichloroethylene in simulated marine environments. Complete dehalogenation of 20 mg L-1 trichloroethylene was achieved within 1 h using 50 mg L-1 biogenic nanopalladium. These biogenic nanoparticles are promising developments for future marine bioremediation applications

Bioremediation of Southern Mediterranean oil polluted sites comes of age

Mediterranean Sea is facing a very high risk of oil pollution due to the high number of oil extractive and refining sites along the basin coasts, and the intense maritime traffic of oil tankers. All the Mediterranean countries have adopted severe regulations for minimizing pollution events and bioremediation feasibility studies for the most urgent polluted sites are undergoing. However, the analysis of the scientific studies applying modern ‘meta-omics’ technologies that have been performed on marine oil pollution worldwide showed that the Southern Mediterranean side has been neglected by the international research. Most of the studies in the Mediterranean Sea have been done in polluted sites of the Northern side of the basin. Those of the Southern side are poorly studied, despite many of the Southern countries being major oil producers and exporters. The recently EU-funded research project ULIXES has as a major objective to increase the knowledge of the bioremediation potential of sites from the Southern Mediterranean countries. ULIXES is targeting four major polluted sites on the coastlines of Egypt, Jordan, Morocco and Tunisia, including seashore sands, lagoons, and oil refinery polluted sediments. The research is designed to unravel, categorize, catalogue, exploit and manage the diversity and ecology of microorganisms thriving in these polluted sites. Isolation of novel hydrocarbon degrading microbes and a series of state of the art ‘meta-omics’ technologies are the baseline tools for improving our knowledge on biodegradation capacities mediated by microbes under different environmental settings and for designing novel site-tailored bioremediation approaches. A network of twelve European and Southern Mediterranean partners is cooperating for plugging the existing gap of knowledge for the development of novel bioremediation processes targeting such poorly investigated polluted site

Rapport pr\ue9liminaire sur les caract\ue8res p\ue9dologiques et la population de mosissures du sol en sub\ue9raies non g\ue9r\ue9es de deux pays de la r\ue9gion m\ue9diterran\ue9enne: Sardaigne et Tunisie

This intervention partially deals with the data obtained within a research project supported by the "NATO Science-for-Peace" program ESP.Md.SFPP 981674, and undertaken by an interdisciplinary consortium of research teams involving three Nato countries and two Mediterranean Dialogue countries. The soil of unmanaged cork oak forests located both in Sardinia and in Tunisia was characterized. The studied Sardinia area was a stand of about 1 ha (40\ub054'48"N,9\ub008'00"E, left unmanaged for about 50 years and located in Cusseddu-Miali-Parapinta, in the Northern part of the island in Tempio Pausania District. This forest is run by Agris Sardegna and certified since 2005 according to the FSC Standards (SA FM/COC-001436). The studied Tunisian area was the cork oak forest located in the site of Ras Rajel (36\ub057'15""N,8\ub051'48"E), in the North-Western part of Tunisia. Soil samples were collected in both areas at the depth of 0-10 cm, according to international standards (ISO 10381-1:2002) to determine the pedological characters (humidity, pH, total organic carbon, total nitrogen content and texture) and the fungi community. The data were tested for significance with analysis of variance (ANOVA) techniques. The soil of the two studied areas were significantly different as far as pH, TOC% and Sand content are concerned. In Sardinia soil the pH values ranged from 5.15 to 6.14, TOC from 4 to 9% and total N from 0.25 to 0.39%. In Tunisia soil the pH values ranged from 6.22 to 7.38, TOC from 3 to 6% and Total N from 0.20 to 0,43%. The texture of Sardinia soil was mainly classified as "sandy-loam" and the Tunisian ones as "sandy-clay-loam" (USDA classification system). As far as the fungi community is concerned in Sardinia soil, the most frequent fungi genere were Trichoderma (18%), Penicillium (15%), and Paecilomyces (13%). in Tunisian soil Penicillium was the dominant genus (54%), and Aspergillus was occurred second n the order of dominance (20%)