Utilisation des lichens comme bio-indicateurs de la pollution atmosphérique par le plomb, cadmium et zinc de la région de Rabat-Sale-Zemmour-Zaêr (Maroc)

Au Nord-Ouest du Maroc, la région de Rabat-Salé-Zemmour-Zaêr présente une importance socioéconomique pour le royaume. En effet, elle est sujette à deux sources de pollution; le trafic routier et les rejets des poteries. Considérant le risque de contamination métallique de l’Homme et de l’environnement, une étude a été conduite pour évaluer la pollution métallique de l’atmosphère. Elle a porté sur les bioindicateurs lichens (Xanthoria Parietina). C’est ainsi que des échantillons de thalle de Xanthoria Parietina ont été prélevés au cours de la période située entre janvier et juillet 2007 et trois éléments métalliques Plomb(Pb), Cadmium(Cd) et Zinc(Zn) ont été détectés. Les résultats de suivi spatial obtenus au niveau des quatre stations étudiées (Kamra, Centre ville, Oulja et Allal Behraoui) ont révélé des concentrations moyennes mensuelles dépassant les normes requises à l’exception de la station de Allal Behraoui. Les résultats de suivi temporel obtenus au niveau des lichens montrent que la variation saisonnière atmosphérique des métaux est très marquée avec des teneurs plus élevées en hiver et plus basses en été.Mots-clés : métaux lourds, lichens, plomb, cadmium, zinc, Rabat, salé, Zemmour, Zaêr, Maroc

Étude de la performance de la STEP du centre emplisseur de la société Salam Gaz – Skhirat, Maroc

Le présent travail a pour but de vérifier l’efficacité du fonctionnement de la STEP de la société Salam Gaz. Les eaux traitées sont réutilisées durant le procédé de production de la société. Les résultats de la caractérisation physicochimique des eaux usées brutes ont montré que les paramètres analysés dépassent les valeurs limites de rejets directes ou indirectes. Les valeurs moyennes en MES, DBO5 et DCO de l’eau brute sont respectivement 3429, 447 et 698 mg/L. Les rendements d’éliminations des paramètres MES, DCO et DBO5 par la STEP sont respectivement 99%, 86%, et 84% alors que l’abattement de la teneur en chrome, cuivre, cadmium et plomb dépasse 90%. Ceci montre que la STEP fonctionne correctement. Toutefois, des améliorations sont nécessaires pour améliorer d’avantages la performance de la STEP. En outre, les eaux usées épurées ont montré un pH acide variant autour de 5 ce qui nécessite une optimisation de la dose du coagulant injecté et une neutralisation avant rejet des eaux traitées dans le milieu récepteur.Mots-clés : eaux usées, diagnostic, performances, recyclage, Salam Gaz – Skhirat, Maroc.Study of the performance of the WWTP filling station company Salam Gas - Skhirat MoroccoThe present work designed to verify the operating effectiveness of society Step Salam Gas. The treated water is reused in the production process of the company. The characterization results at selected tapping points show that the majority of the analyzed parameters exceed the limit values for discharges. The mean values of TSS, BOD5 and COD of raw water are respectively 3429, 447 and 698 mg/l. Yields eliminations parameters TSS, COD and BOD5 by STEP are respectively 99%, 86% and 84% while the reduction of chromium, copper, cadmium and lead in excess of 90%. This shows that STEP is working properly. However, improvements are needed to improve the performance benefits of STEP. In addition, the treated wastewater showed an acidic pH ranging around 5 which requires an optimization of the dose of coagulant injection and neutralization prior to discharge treated wastewater into the receiving environment.Keywords : Wastewater, diagnostic, performance, recycling performance, Salam Gaz – Skhirat, Morocco

Croissance et capacité reproductive d’Hypnea musciformis (Rhodophyceae, Gigartinale) de la côte atlantique marocaine

Les algues carraghénophytes constituent une biomasse importante sur le littoral marocain et sont exportées à l’état brut sans transformation locale, alors que l’industrie de l’agar est très développée au Maroc. Le but de notre travail est la valorisation des espèces les plus abondantes en vue de leur transformation locale. Hypnea musciformis est l’une des espèces étudiées au laboratoire et constitue une candidate potentielle à l’exploitation. Sa valorisation passe par l’étude de sa biologie en milieu naturel, puis en conditions contrôlées. Les variations saisonnières de la croissance et de la capacité reproductive de l’algue rouge Hypnea musciformis ont été suivies durant deux années dans deux localités différentes au niveau de la côte atlantique marocaine. L’étude a permis de montrer que l’espèce est fertile toute l’année avec une large dominance de la génération tétrasporophytique, et présente deux périodes actives de croissance ; la première estivale et la seconde de moindre importance, automnale. Ainsi, le cycle biologique de l’algue se trouve influencé par plusieurs facteurs environnementaux tels que la lumière, la température, la salinité, la position de l’espèce au niveau de l’estran et les réponses d’acclimatation de l’algue aux différents types d’habitats.Mots-clés : Hypnea musciformis, croissance, reproduction, analyse statistiqu

Contribution to the study of the hydrochemical characteristics of the Ramsar site: Afenourir Lake, Morocco

In order to better understand and manage the surface water quality of wetlands case of the Afenourir Ramsar site, located to the south of the Ifrane National Park in the Central Middle Atlas, an assessment of the water quality was carried out during the sampling campaign June 2015-March 2018. Spatiotemporal monitoring and analysis of the different physicochemical tracers in-situ (temperature, pH, electrical conductivity, dissolved oxygen) and in the laboratory (nitrites, nitrates, orthophosphates, sulphates), revealed on the one hand the temporary influence of climatic hazards (precipitation, floods, drought) and on the other hand the anthropic influence. For example, the surface water quality of Lake Afenourir can witness to a deterioration of the wetland, which would enhance an emergency management and management plan for the lake urgent

Feather’s Passer domesticus as a non invasive bio-indicator tool of urban heavy metals (Zn, Pb, Cd) pollution in Rabat-Salé (Morocco).

  The purpose of this study is to evaluate the rate of heavy metals (Zinc, Lead and Cadmium) in industrial and urban areas of Rabat using Feather’s  Passer domesticus as a non invasive  bio-indicator method. The collection was made on 50 house sparrows (Passer domesticus) males and females, which were captured in five different sites of Rabat, (ten specimens by site), according to the road traffic and industrial activities, the results obtained indicate the presence of metals in all the analyzed samples. Cd is above the threshold of contamination (0.1 ppm) for all sites, while the Pb far exceeds the threshold (4 ppm) for two study sites. These results suggest that we have two major sources of contamination by heavy metals: Road traffic, and Industrial activities

Ultrasound-assisted adsorption of Methyl Parathion using commercial Granular Activated Carbon from aqueous solution

The removal of Methyl parathion (MP) by ultrasound-assisted adsorption using commercial Granular Activated Carbon (GAC) was studied. The effect of sonicate time on the adsorption were studied using the batch technique. The adsorption kinetic data were analyzed using the Pseudo First Order (PFO) and Pseudo Second Order (PSO) models. For kinetic study, the adsorption process fitted the PSO model. Three adsorption isotherms namely the Langmuir, Freundlich and Redlich–Peterson isotherms in their non-linear forms were applied to the adsorption equilibrium data. Both the Langmuir and Redlich–Peterson models were found to fit the adsorption isotherm data well, but the Redlich– Peterson model was better. The monolayer adsorption capacity, qm, was found to be 20.20 mg g-1. It can be concluded that the commercial GAC is an efficient adsorbent for the removal of MP from aqueous solution via ultrasound-assisted adsorption. Attempt to explain the reactivity of MP on GAC by theoretical calculations was made

Variabilités des descripteurs physiques, chimiques et biologiques d'un réservoir de stokage (lagunage mixte, en Slimane - Maroc)

L'étude des variations des descripteurs physiques, chimiques et biologiques des eaux d'un réservoir de maturation du lagunage mixte (Ben Slimane, Maroc), a montré une augmentation des valeurs de certaines variables (oxygène dissous, transparence) après le 36ème jour de rétention en raison d'une remise en solution.A 36 jours de rétention, la chute des teneurs de la DBO5, de la DCO, des composés azotés (NH4+, NO3-, NTK) et phosphorés (PO43-, PT), et l'augmentation du pH, de l'oxygène dissous et de la transparence laissent présager une maturation à cette date de mesure. Les densités planctoniques enregistrées à ce niveau sont les plus basses.Au-delà de ce stade de maturation, le phytoplancton prolifère avec dominance d'Euglena viridis qui montre un pic de densité (4,1.106 Individus/m3) le 81ème jour. Le début de sa phase exponentielle de croissance est observé à partir du 18ème jour de maturation. La densité cellulaire est ensuite atténuée vraisemblablement en raison de la diminution de la charge organique (DBO5 et DCO) après le 81ème jour et de l'intensité de broutage par le zooplancton herbivore surtout Acanthocyclops robustus qui montre son maximum de croissance le 138ème jour.Après le 81ème jour de maturation, Euglena viridis est remplacée par deux espèces de Chlorophycées (Pediastrum boryanum et Ankyra judai) dont le maximum de densité (91% de la densité algale totale) est atteint le 138ème jour. La prolifération de ces espèces coïncide avec des valeurs en nitrates dépassant 10,6 mg N/L.A la fin de cette période d'étude (le 138ème jour), le zooplancton est à sa prolifération maximale (106 individus/m3). Il est dominé par Acanthocyclops robustus avec présence de Nauplii et de Daphnia magna. Les Rotifères présents depuis le début de la maturation disparaissent à 138 jours de rétention. L'étude bactériologique a révélé un rendement épuratoire remarquable atteignant 100% pour les coliformes fécaux et les streptocoques fécaux.A study of physical, chemical and biological descriptors of the water in the storage reservoir of a combined stabilization pond (Ben Slimane, Morocco), during maturation, showed an improvement of the purification output for some variables after 36 days of retention. Such an environment, rich with a range of different nutrients, allowed an optimal development of plankton characterized by a high species diversity that decreased with time. Zooplankton development seemed to be limited by poor phytoplankton biomass. However, trophic factors such as nutrients and temperature affected the evolution of planktonic species.After 36 days of retention, the decrease in BOD5, COD, NH4+, NO3-, total Kjeldahl nitrogen (TNK), PO43-, total phosphorus (TP), and the increase in pH, dissolved oxygen and transparency, suggested that maturation had been reached at this level. Simultaneously, phyto- and zooplankton were present in low densities. Nevertheless, beyond this stage of maturation, phytoplankton proliferation occurred, dominated by Euglena viridis whose exponential phase of growth began at the 18th day of maturation and reached a maximum density after 81 days (4.1x106 individus/m3). A low proportion of Chlorophyte species was observed, represented by Pediastrum boryanum and Ankyra judai. The zooplankton community was dominated by two species of Cladocera (Daphnia magna and Diaphanosoma sp).The increase in Euglena viridis density up to 81 days coincided with zooplanktonic proliferation constituted exclusively by Rotifers (Brachionus calyciflorus and Polyarthra remata). At 111 days of retention, the zooplankton community consisted of Copepods (Acanthocyclops robustus), which reappeared at this stage, as well as Nauplii Cladocera (Daphnia magna) and residual Rotifers (Brachionus calyciflorus and Polyarthra remata). The remarkable decrease in Euglena density on day 111 and their complete disappearance on day 138 was probably linked to grazing by herbivorous zooplankton and to low organic matter concentrations. Euglena viridis was replaced by two Chlorophytes (Pediastrum boryanum and Ankyra judai) reaching their maximum density (91% of total algal density) on day 138. The proliferation of these species coincided with values exceeding 10.6 mg N/L. Zooplankton were dominated by Acanthocyclops robustus with the presence of Nauplii and Daphnia magna (106individuals/m3). Rotifers were present since the beginning of the maturation, but were absent by 138 days of retention.The qualitative and quantitative changes in phyto- and zooplankton result from factors that control the growth and the loss of these populations. A low growth rate can lead to biomass accumulation if the growth exceeds loss. On the other hand, a low and stable biomass can result from a high growth rate that is compensated by important losses. Zooplankton grazing and algal sedimentation, which are the two main mechanisms related to phytoplankton decline, are two selective processes (POURRIOT et al., 1982). In stabilization ponds, food chains are established that allow water clarity and minimize algal proliferation. The bacteriological study showed a remarkable purification, with reductions reaching 100% for faecal coliforms and faecal Streptococcus

Evaluation of the impact of wastewater in the rural commune of Jmaa Moulblad on the bacteriological water quality of the Grou River (Rabat region, Morocco)

In the region of Rabat, shallow watercourses are currently threatened by the magnitude of urban and industrial discharges, mainly due to its growing demography and the continuous development of the agricultural and industrial sectors. This study aims to evaluate the impact of wastewater from the rural commune of Jmaa Moulblad on the bacteriological water qualityof the Grou River. In order to measure the pollution levels of this watercourse, our study focused on the enumeration of fecal contamination indicator bacteria such as total coliforms (TC), faecal coliforms (FC) and intestinal enterococci (EI), as well as the detection of salmonella. Water samples were taken by season during the 2016/2017 period at four stations on the Grou River. The results obtained describe a worrying state of the watercourse, particularly at the S2 station located directly at the mouth of the wastewater of the rural commune of Jmaa Moulblad which is rejected without prior treatment. If protective measures are not taken, the perpetual degradation of the quality of these waters would certainly lead to the loss of this watercourse, which is of paramount importance in the region.

Multivariate analysis and A GIS-based method to assess surface water quality in the Sakia El Hamra River Near Laâyoune City, Morocco

In the Laâyoune Sakia El Hamra region of Morocco, characterized by scarcity, fragility, and uneven distribution of water resources, acute water stress is prevalent due to overexploitation, climate change, and the escalating degradation of water quality from human activities. The Sakia El Hamra River, a vital watercourse, is subjected to continuous pollution from domestic waste and untreated wastewater from Laâyoune city, impacting a section designated as a Ramsar site. This study aims to enhance understanding of these impacts within the region. A series of physicochemical parameters were monitored spatiotemporally at multiple points along the river, both upstream and downstream of the Sakia El Hamra dam. The findings indicate that while the reservoir water maintains acceptable quality, influenced by evaporation, the salinity levels do rise. Conversely, the downstream water quality exhibits excessive mineral concentrations, far surpassing acceptable standards, as evidenced by elevated electrical conductivity. Furthermore, significant pollution levels are confirmed by high measurements of biochemical oxygen demand, chemical oxygen demand, total phosphorus, ammoniacal nitrogen, and other contaminants.  The mapping of water quality indicators in the Oued Sakia El Hamra River, was achieved using a Geographical Information System (GIS) based on the Water Quality Information System and spatial analysis with Inverse Distance Weighted (IDW) interpolation. The analysis reveals that the water quality downstream poses a substantial risk to the Foum El Oued aquifer and the local aquatic ecosystem, especially in zones affected by wastewater discharge and spring runoff. Mapping water quality will help to monitor and enforce standards and regulations to manage and control pollution