CONTRIBUTION À L’ÉTUDE DE LA BIOACCUMULATION MÉTALLIQUE DANS LES SÉDIMENTS ET LES ORGANISMES AQUATIQUES DU LITTORAL DE SAIDIA (MAROC ORIENTAL)

The result of the coastal metal contamination in the extreme East of Morocco was based on sampling and the search for metal contamination by lead, zinc, cadmium, and iron respectively. This search was done in marine water, sediments, and in the sea. Urchin Paracentrotus lividus; benthic echinoderm is common in the eastern Mediterranean coast of Morocco with two sampling series (July 2011 and March 2012). The objective of this study is to evaluate the distribution of some heavy metals in the Saidia coastline, through the Biological indicator, Paracentrotus lividus. The heavy metal content (iron, zinc, lead and cadmium) in water, sediment, and marine organisms, were studied in four stations at the coast Saidia. The study revealed the presence of very high concentrations of metals, especially with regard to iron and zinc. Lead has relatively high values, while the cadmium is virtually absent in all samples. However, the results support a finding which is similar to the bio-accumulated metals by the sea urchin elements and those detected in water and sediment. The existence of a significant correlation between iron, zinc, and lead shows that there is a high chemical affinity between these three metals. Overall, this study allows us to identify the presence of heavy metals in water, sediment, and aquatic organisms of coastal Saidia, which is seriously disrupted by various domestic discharges, port, industrial and agricultural wastes

CONTRIBUTION À L’ÉTUDE DE LA BIOACCUMULATION MÉTALLIQUE DANS LES SÉDIMENTS ET LES ORGANISMES AQUATIQUES DU LITTORAL DE SAIDIA (MAROC ORIENTAL)

The result of the coastal metal contamination in the extreme East of Morocco was based on sampling and the search for metal contamination by lead, zinc, cadmium, and iron respectively. This search was done in marine water, sediments, and in the sea. Urchin Paracentrotus lividus; benthic echinoderm is common in the eastern Mediterranean coast of Morocco with two sampling series (July 2011 and March 2012). The objective of this study is to evaluate the distribution of some heavy metals in the Saidia coastline, through the Biological indicator, Paracentrotus lividus. The heavy metal content (iron, zinc, lead and cadmium) in water, sediment, and marine organisms, were studied in four stations at the coast Saidia. The study revealed the presence of very high concentrations of metals, especially with regard to iron and zinc. Lead has relatively high values, while the cadmium is virtually absent in all samples. However, the results support a finding which is similar to the bio-accumulated metals by the sea urchin elements and those detected in water and sediment. The existence of a significant correlation between iron, zinc, and lead shows that there is a high chemical affinity between these three metals. Overall, this study allows us to identify the presence of heavy metals in water, sediment, and aquatic organisms of coastal Saidia, which is seriously disrupted by various domestic discharges, port, industrial and agricultural wastes

Evaluation de la phytotoxicité et du stress salin des sols de l’ancienne décharge publique de la ville d’Oujda : Bio-essais de laboratoire

The ecotoxicity of soil contaminated by urban waste’s leachate is very complex. The evaluation of their phytotoxicity requires the use of a battery of tests in laboratory. Grounds polluted by the leachate of the old landfill of Oujda city (Eastern Morocco) inhibit the seeding of a resistance botanical species (barley) and cause a reduction of the foliar and root productivity of chlorophytum plant. The decrease of the air and subterranean biomass as well as the growth in height in the various polluted grounds is statistically significant. The accumulation of the proline in leaves and roots of the plant of chlorophytum (spider plant), highlighted a salt stress. It seems however that, for an ecological rehabilitation of the old landfill of Oujda city after its closure, the choice of halophile vegetation is necessary.L’écotoxicité des sols pollués par les lixiviats des ordures ménagers est très complexe. L'évaluation de leur phytotoxicité impose l'utilisation d'une batterie de tests en laboratoire. Les sols pollués par les lixiviats de l’ancienne décharge publique de la ville d’Oujda (Maroc Oriental) inhibent la germination d'une espèce végétale résistante à la pollution minérale et métallique (orge) et provoquent une réduction de la productivité foliaire et racinaire de chlorophytum. La diminution de la biomasse aérienne et souterraine ainsi que la croissance en hauteur de cette plante cultivée sur différents sols pollués est statistiquement significative. L’accumulation de la proline dans les tissus foliaires et racinaire du chlorophytum mis en évidence un stress salin. Il apparaît  ainsi que,  pour une réhabilitation écologique de la décharge publique des la ville d’Oujda après sa fermeture, le choix d’une espèce végétale halophile est indispensable

Physico-chemical characterization of water and metallic contamination of Mytilus galloprovincialis in the coastal zone of Saidia

Water is a vital natural resource for life. The metal pollution of aquatic ecosystems is increasing due to the effects of urbanization and industrialization. As a result, heavy metals contamination has become a serious threat to public health because of their toxicity, long persistence, bioaccumulation, and biomagnification in the food chain. This investigation aims to evaluate seawater's Physico-chemical quality and assess the contamination risks of Mytilus galloprovincialis mussels by Cadmium, Zinc, Iron, and Copper. The study was carried out in three stations of Saidia coast during July 2019. The seawater was analyzed for its Physico-chemical parameters, and ICP-AES determined the heavy metals content in mussels. The results show that the tested water has a pH value ranging between 7.48-7.62 with nitrate and nitrite content range between 0-4.78 mg/L, 0.007-0.181 mg/L, respectively. The recorded water conductivity and oxydability values ranged from 22 to 55 mS/cm and from 5.67 to 10.47 mg/L. The mean concentration found in the mussels were in decreasing order, Iron (13.5 mg/kg), Zinc (2.3 mg/kg), Copper (0.65 mg/kg) and Cadmium (0.02 mg/kg), respectively. The obtained results indicate that all values are below the threshold recommended by Food and agriculture organization and world health organization

Investigation du lessivage des stocks de boues d’épuration de Nador : Étude sur terrain et apport de l’expérimentation

La station d’épuration par boues activées de Nador génère de grandes quantités de boues qui posent un sérieux problème environnemental. Ces boues sont stockées à côté de la lagune de Nador, sans aucune mesure assurant leur innocuité à l’environnement. Pendant la période pluvieuse, les eaux de pluies s’infiltrent à l’intérieur des déchets en se chargeant de leurs composés minéraux et organiques générant ainsi un lixiviat. Notre étude vise à caractériser le lixiviat des stocks de boues et à approcher expérimentalement via un test de percolation le risque du transfert possible des contaminants issus de ces stocks vers les ressources d’eau. Les analyses physico-chimiques des lixiviats des stocks de boue ont montré qu’ils sont riches en azote Kjeldhal (NTK max = 1 436 mg•L-1), en nitrates (NO3 max = 88,6 mg•L-1), en PT (PT max = 88,79 mg•L-1) et en PO4 (PO4 max = 20,87 mg•L-1). En outre, ces lixiviats présentent des teneurs assez élevées en SO4, Cl, Ca, Mg, Na et K. Ces lixiviats contiennent également des métaux lourds, principalement le Cu et le Zn. Le test de percolation réalisé a permis de mettre en évidence un lessivage important d’azote et de phosphore à partir des boues en comparaison avec le témoin (le sol). En effet, les quantités de NO3, NH4, NTK, PO4 et PT exportées par lessivage à travers les boues sont respectivement 8 fois, 21 fois, 35 fois, 3 fois et 18 fois plus élevées en comparaison avec les valeurs témoins. Par ailleurs, la charge lessivée des boues en métaux lourds (Cd, Cr, Cu, Ni, Pb, Zn) représente 0,07 % de la charge initiale, ce qui est approximativement le double de la charge lessivée à partir du sol.The wastewater treatment plant (WTP) of Nador, using an activated sludge process, generates large quantities of sludge, which create a serious environmental problem. The sludge is stored near the Nador lagoon, without any measures to ensure protection of the environment. During the rainy period, the rain water seeps through the waste, extracting minerals and organic compounds and generating a leachate. Our study aimed to characterize the leachate from the stocked sludge and to explore experimentally, using a percolation test, the risk of contamination of water resources. The results of physico-chemical analysis showed that the leachate is rich in total Kjeldhal nitrogen (TKN max = 1,440 mg•L-1), nitrate (NO3 max = 88.6 mg•L-1), total phosphorus (TP max = 88.8 mg•L-1) and orthophosphate (PO4 max = 20.9 mg•L-1). In addition, the leachate has high contents of SO4, Cl, Ca, Mg, Na and K. The leachate also contains heavy metals, mainly Cu and Zn. The percolation test indicates important levels of nitrogen and phosphorus leached from the sludge in comparison to the soil control. Furthermore, the quantities of NO3, NH4, TKN, PO4 and TP exported by leaching through the sludge are respectively, 8 fold, 21 fold, 35 fold, 3 fold and 18 fold higher than those leaching through soil. In addition, the levels of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn) leached from sludge (0.07% of the initial load) are 2 fold higher than the levels leached from soil

Impact of mine waste on the quality of surrounding agricultural soils in Toussit and Sidi Boubker, Morocco: a case study

The Oriental region, in Morocco, is surrounded by the Algerian border to the East, the Atlas to the West, the Mediterranean to the North and the desert to the south. This region has benefited from the intense mining activity that has played an important role in the national economy. The intensification of mining activity in the Touissit and Sidi-Boubker mines has left behind the closure of tons of waste in the shelter without a plan of conservation. These mine waste storage sites still contain very high levels of metallic elements such as Iron (Fe), which, after a decade of shutdowns, are likely to pollute vulnerable receiving environments, posing a threat to wildlife ecosystems, flora, and to public health. The objective of this study was to assess Fe concentrations at several locations around these mine waste heaps. The results of physicochemical analyses of soils collected over two different periods (wet and dry seasons) showed maximum Fe element concentrations of 10596 mg/kg, with an average concentration of 8913 mg/kg. These Iron contents are found at concentrations exceeding tolerance standards for normal soil

Study of the spatiotemporal variation of iron and manganese ions content in the Oued Moulouya water (North-East of Morocco)

Oued Moulouya is one of the most important water resources, not only for water supply, but also for the agro-industrial development of the North-East region of Morocco. However, the remarkable modification in terms of physico-chemical quality of this water resource which is constantly expressed by high concentrations of various mineralogical and organic components. This calls for the necessary measures to be taken to remedy this pollution. To understand the contribution of each source of this imbalance, whether geological and/or anthropogenic, we conducted a study to monitor, during the both wet and dry periods, the spatiotemporal variations of iron and manganese ions at eight stations along the Oued Moulouya. The water samples collected were therefore analysed to determine their pH (in situ) and their contents in these two ions following the method of Inductive Coupled Plasma spectrometry. The results obtained showed disparities in the concentrations of various components between the two periods of the year: wet and dry periods. Thus, the two elements monitored (Fe and Mn), expressed their maximum levels during the dry period, with values of 21.75 mg/l and 4.9 mg/l. These values were recorded at the station near the city of Guercif. While the minimum concentrations of these elements were recorded upstream of the Oued during the rainy months with values of 0.047 mg/l for iron and 0.016 mg/l for manganese. Hence, it is concluded, that the variation of the content of these two elements Fe and Mn is influenced by the geochemical contribution, which occurs during the dry periods and decreases by the physical dilution during the rainy periods

Influence de rejets d’eaux usées sur les qualités physicochimique et bactériologique d’eaux utilisées en irrigation

Les ressources en eau au Maroc sont limitées en raison du climat semi-aride qui caractérise la majeure partie du territoire. A ceci s’ajoute les sècheresses épisodiques. Cette problématique ne se limite pas à la quantité des ressources en eau, mais porte également sur la qualité de ces ressources qu’il faut aujourd’hui plus que jamais bien gérer. Les activités (industrielles, agricoles ou urbaines) peuvent affecter la qualité des eaux et les rendre impropres à l’utilisation. C’est le cas de la région de Meknès où la diversification et l’augmentation de la quantité d’effluents rejetés sans traitement détériorent grandement le milieu aquatique.L’évaluation de l’impact de ces rejets sur les caractéristiques physico-chimiques et microbiologiques de l’oued Bouishak, durant la période allant de juillet 2005 jusqu’à juin 2006, a montré que les eaux usées brutes domestiques et industrielles, le plus souvent rejetées dans le cours d’eau sans aucun traitement préalable, nuisent fortement a la qualité de ces eaux de surfaces. Les paramètres physicochimiques et bactériologiques mesures au niveau de ce cours d’eau évoluent de manière graduelle de l’amont vers l’aval : faibles à l’amont et élevés à l’aval, à proximité des zones de réutilisation des eaux usées en agriculture. L’étude bactériologique a révélé une forte contamination fécale des eaux de l’oued Bouishak dépassant les normes édictées par l’OMS pour une irrigation des cultures vivrières

Assessment of denitrification using electrocoagulation process

International audienc

Comparative Evaluation of Biogas Yield and Physicochemical Properties of Three-Phase and Traditional Olive Oil Mill Wastes – The Most Suitable Choice for Efficient Anaerobic Digestion

Olive oil mill waste is characterized by its high organic matter content, especially fatty acids, polyphenols, sugars, and proteins. These nutrients can be used as a source of energy for biogas production. However, olive oil mill waste can also contain heavy metals such as lead, cadmium, copper, and zinc that can be absorbed by plants. In addition, very high concentrations of heavy metals can also inhibit the anaerobic digestion process by affecting the methanogenic bacteria involved in biogas production The aim of this research is to determine the composition of solid and liquid rejections from traditional and continuous three-phase crushing systems, by analyzing samples from different oil mills in the eastern region of Morocco. We also applied the technology of anaerobic digestion of solid and liquid waste forms of oil mills, to make a link between the biogas yield and the physicochemical characteristics of these wastes. The results suggest that traditional oil mill wastewater (Discontinuous OMWW) has high organic matter, nutrients, and heavy metals content and a low concentration of phenolic compounds, which can increase its biogas production potential with a production of 10.02 Nml/ g VS, while three-phase wastewater (Continuous OMWW) has limited biogas production potential (3.83 Nml/ g VS) due to the low organic matter and nutrients content, and high concentration of phenolic compounds. Three-phase olive pomace (Continuous OMSW) has a higher biogas production (9.28 Nml/ g VS) than traditional olive pomace (Discontinuous OMSW) with 5.91 Nml/ g VS. In fact, the lower content of phenolic compounds and volatile fatty acids favors their anaerobic digestion and improves their biogas production. In conclusion, the selection of the type of waste adapted for biogas production must be based on the physicochemical and microbiological characteristics of these wastes