Characterization and quantification of anthropogenic and industrial inputs in the Sebou River basin

L’objectif principal de ce travail de thèse est d’évaluer l'impact des activités anthropiques sur le fonctionnement des systèmes aquatiques. L’impact des rejets urbains de Fès sur le Sebou, l'une des plus grandes rivières du Maroc, a été choisi pour cette étude. Les eaux usées domestiques et industrielles de la ville de Fès (~1M hab), véhiculées par son affluent l’oued Fès, sont rejetées dans le Sebou quasiment sans traitement. Deux sites du Sebou, en amont et en aval des rejets de la ville de Fès, et un site situé sur l’oued Fès ont été étudiés. Une campagne de prélèvement de carottes de sédiments et onze campagnes mensuelles de prélèvement d’eau et de matières en suspension (MES) ont été effectuées dans le but de quantifier les apports en nutriments, éléments traces métalliques (ETM) et carbone organique afin d’étudier la dynamique de ces polluants. Les résultats obtenus ont mis en évidence une augmentation des concentrations de presque tous les éléments étudiés en aval de la ville de Fès aussi bien dans la colonne d’eau que dans les sédiments. L’étude des carottes sédimentaires a révélé une contamination modérée par les butylétains totaux (ΣBT) avec la prédominance du monobutyétain dans les trois sites d’étude et sur toutes les profondeurs. Les sédiments du Sebou, en amont de la ville de Fès se caractérisent par les teneurs les plus faibles en métaux alors que ceux de l’oued Fès présentent une forte pollution polymétallique, accentuée dans les sédiments de surface, ce qui reflète clairement la signature d'apports anthropiques récents résultant des rejets non traités de la ville de Fès. L’augmentation consécutive des teneurs des métaux dans les sédiments du Sebou en aval de la confluence Fès-Sebou traduit l'influence significative des particules polluées de l’oued Fès. Dans la colonne d’eau, les concentrations mesurées dans le Sebou en amont de la confluence Fès-Sebou sont proches des rivières naturelles, à l’exception de Cl-, Cr, Na+ et NO3- dont les concentrations traduisent des pollutions agricoles et/ou domestiques. En revanche, la signature anthropique des rejets de la ville de Fès apparait évidente dans les eaux de l’oued Fès qui montrent des concentrations très élevées en ETM dissous et particulaires. La majorité des ETM provenant des apports anthropiques subissent des changements importants de leur coefficient de distribution Kd et présentent un comportement non conservatif dans le mélange entre les eaux du Sebou et celles de l’oued Fès. Ces résultats ont été confirmés par le modèle WHAM qui permet de prédire correctement le fractionnement dissous/particulaire, du Cu, Pb et Zn. La spéciation chimique de ces éléments ainsi que leur répartition dissous/particulaire apparaissent significativement influencées par les conditions particulières (anoxie, forte contamination, teneurs importantes en matière organique) des eaux de l’oued Fès. Ces conditions sont aussi à l’origine du comportement non conservatif de la majorité des éléments lors d'un mélange Sebou/Fès, observé aussi bien dans la colonne d’eau que dans les sédiments.The main goal of this PhD was to evaluate the impact of the anthropogenic activities (urban, industrial or agricultural activities) on aquatic systems. The Fez metropolitan area and its impacts on the Sebou River, the main Moroccan river, were chosen as a case study. The Fez agglomeration (~1M hab), is surrounded by the Fez River, receiving the wastewaters of this developing city and then flowing into the Sebou. This work was performed on two sites along the Sebou River (upstream and downstream from the confluence with Fez River), and one site in the Fez River, downstream from the Fez city. One sampling campaigns of sediment cores and eleven sampling campaigns were performed during low flow conditions to quantify nutrients, organic carbon and trace metals and to study the dynamic and the transport of trace elements in the Sebou and Fez rivers. The obtained results revealed a global increase of studied elements in the Sebou River from upstream to downstream sampling site, in both sediments and water column. A moderate level of contamination by butyltins was observed, with monobutyltin being the dominant species across all sites and depths. The lowest level of metal pollution was identified in the Sebou's sediments upstream Fez city. Whilst the Fez' sediments were heavily polluted and exhibited bottom-up accumulation trends, which clearly evidence recent inputs from the untreated wastewaters of Fez city. The increase of metal levels in Sebou downstream sediments reflects a significant contribution of polluted particles from the Fez River. Dissolved and particulate concentrations of most of the analyzed elements in the Sebou, upstream from Fez city, are close to the natural rivers, except Cl-, Cr, Na+ et NO3- probably due to untreated urban inputs from several small/medium-size towns located upstream Fez. In the opposite On the contrary, high dissolved and particulate trace metals concentrations in the Fez River clearly indicated strong anthropogenic inputs from Fez city. Most of the studied trace metals originated from anthropogenic sources, underwent significant changes of Kd and behaved non-conservatively in the Sebou/Fez waters mixing due to drastic changes of the waters quality (anoxic condition, high concentration, high organic matter content). Dissolved/particulate partitioning were correctly assessed by WHAM-VII modeling for Cu, Pb and Zn, depicting significant differences in chemical speciation in Fez River when compared to Sebou one

Caractérisation et quantification de la charge polluante anthropique et industrielle dans le bassin du Sebou

The main goal of this PhD was to evaluate the impact of the anthropogenic activities (urban, industrial or agricultural activities) on aquatic systems. The Fez metropolitan area and its impacts on the Sebou River, the main Moroccan river, were chosen as a case study. The Fez agglomeration (~1M hab), is surrounded by the Fez River, receiving the wastewaters of this developing city and then flowing into the Sebou. This work was performed on two sites along the Sebou River (upstream and downstream from the confluence with Fez River), and one site in the Fez River, downstream from the Fez city. One sampling campaigns of sediment cores and eleven sampling campaigns were performed during low flow conditions to quantify nutrients, organic carbon and trace metals and to study the dynamic and the transport of trace elements in the Sebou and Fez rivers. The obtained results revealed a global increase of studied elements in the Sebou River from upstream to downstream sampling site, in both sediments and water column. A moderate level of contamination by butyltins was observed, with monobutyltin being the dominant species across all sites and depths. The lowest level of metal pollution was identified in the Sebou's sediments upstream Fez city. Whilst the Fez' sediments were heavily polluted and exhibited bottom-up accumulation trends, which clearly evidence recent inputs from the untreated wastewaters of Fez city. The increase of metal levels in Sebou downstream sediments reflects a significant contribution of polluted particles from the Fez River. Dissolved and particulate concentrations of most of the analyzed elements in the Sebou, upstream from Fez city, are close to the natural rivers, except Cl-, Cr, Na+ et NO3- probably due to untreated urban inputs from several small/medium-size towns located upstream Fez. In the opposite On the contrary, high dissolved and particulate trace metals concentrations in the Fez River clearly indicated strong anthropogenic inputs from Fez city. Most of the studied trace metals originated from anthropogenic sources, underwent significant changes of Kd and behaved non-conservatively in the Sebou/Fez waters mixing due to drastic changes of the waters quality (anoxic condition, high concentration, high organic matter content). Dissolved/particulate partitioning were correctly assessed by WHAM-VII modeling for Cu, Pb and Zn, depicting significant differences in chemical speciation in Fez River when compared to Sebou one.L’objectif principal de ce travail de thèse est d’évaluer l'impact des activités anthropiques sur le fonctionnement des systèmes aquatiques. L’impact des rejets urbains de Fès sur le Sebou, l'une des plus grandes rivières du Maroc, a été choisi pour cette étude. Les eaux usées domestiques et industrielles de la ville de Fès (~1M hab), véhiculées par son affluent l’oued Fès, sont rejetées dans le Sebou quasiment sans traitement. Deux sites du Sebou, en amont et en aval des rejets de la ville de Fès, et un site situé sur l’oued Fès ont été étudiés. Une campagne de prélèvement de carottes de sédiments et onze campagnes mensuelles de prélèvement d’eau et de matières en suspension (MES) ont été effectuées dans le but de quantifier les apports en nutriments, éléments traces métalliques (ETM) et carbone organique afin d’étudier la dynamique de ces polluants. Les résultats obtenus ont mis en évidence une augmentation des concentrations de presque tous les éléments étudiés en aval de la ville de Fès aussi bien dans la colonne d’eau que dans les sédiments. L’étude des carottes sédimentaires a révélé une contamination modérée par les butylétains totaux (ΣBT) avec la prédominance du monobutyétain dans les trois sites d’étude et sur toutes les profondeurs. Les sédiments du Sebou, en amont de la ville de Fès se caractérisent par les teneurs les plus faibles en métaux alors que ceux de l’oued Fès présentent une forte pollution polymétallique, accentuée dans les sédiments de surface, ce qui reflète clairement la signature d'apports anthropiques récents résultant des rejets non traités de la ville de Fès. L’augmentation consécutive des teneurs des métaux dans les sédiments du Sebou en aval de la confluence Fès-Sebou traduit l'influence significative des particules polluées de l’oued Fès. Dans la colonne d’eau, les concentrations mesurées dans le Sebou en amont de la confluence Fès-Sebou sont proches des rivières naturelles, à l’exception de Cl-, Cr, Na+ et NO3- dont les concentrations traduisent des pollutions agricoles et/ou domestiques. En revanche, la signature anthropique des rejets de la ville de Fès apparait évidente dans les eaux de l’oued Fès qui montrent des concentrations très élevées en ETM dissous et particulaires. La majorité des ETM provenant des apports anthropiques subissent des changements importants de leur coefficient de distribution Kd et présentent un comportement non conservatif dans le mélange entre les eaux du Sebou et celles de l’oued Fès. Ces résultats ont été confirmés par le modèle WHAM qui permet de prédire correctement le fractionnement dissous/particulaire, du Cu, Pb et Zn. La spéciation chimique de ces éléments ainsi que leur répartition dissous/particulaire apparaissent significativement influencées par les conditions particulières (anoxie, forte contamination, teneurs importantes en matière organique) des eaux de l’oued Fès. Ces conditions sont aussi à l’origine du comportement non conservatif de la majorité des éléments lors d'un mélange Sebou/Fès, observé aussi bien dans la colonne d’eau que dans les sédiments

Regional variations of cytochrome oxidase activity in the central auditory system of Reln(rl-Orl) (reeler) mutant mice.

Despite preserved cell differentiation, the Reln(rl-Orl) phenotype comprises laminar abnormalities of cell position in auditory cortex and dorsal cochlear nucleus. The metabolic consequences of the cell ectopias were determined by estimating cytochrome oxidase (CO) activity, a marker of neuronal activity. CO activity increased in the granular cell layer of dorsal cochlear nucleus, trapezoid body nucleus, intermediate lateral lemniscus, central and external inferior colliculus, and pyramidal cell layer of primary auditory cortex. On the contrary, CO activity decreased in the superficial molecular layer of dorsal cochlear nucleus as well as in the medioventral periolivary nucleus. These metabolic variations are discussed in terms of their possible relation to morphologic anomalies observed in the mutant

Motor coordination in mice with hotfoot, Lurcher, and double mutations of the Grid2 gene encoding the delta-2 excitatory amino acid receptor.

Grid2(ho/ho) is a loss of function gene mutation resulting in abnormal dendritic arborizations of Purkinje cells. These mutants were compared in a series of motor coordination tests requiring balance and equilibrium to nonataxic controls (Grid2(ho/+)) and to a double mutant (Grid2(ho/Lc)) with an inserted Lc mutation. The performance of Grid2(ho/ho) mutant mice was poorer than that of controls on stationary beam, coat hanger, unsteady platform, and rotorod tests. Grid2(ho/Lc) did not differ from Grid2(Lc/+) mice. However, the insertion of the Lc mutation in Grid2(ho/Lc) potentiated the deficits found in Grid2(ho/ho) in stationary beam, unsteady platform, and rotorod tests. These results indicate a deleterious effect of the Lc mutation on Grid2-deficient mice

Regional brain variations of cytochrome oxidase activity in Relnrl-orl mutant mice

Cell malpositioning has been described in laminated structures of the spontaneous mutation, reeler, including the cerebellum, the hippocampus, and the neocortex. Despite the ectopic positions of different neuronal populations, the specificity of synaptic connections is maintained. The metabolic consequences of this form of neuropathology were examined in Relnrl mutant mice by quantitative measures of cytochrome oxidase (CO) activity, a mitochondrial enzyme essential for oxidative metabolism in neurons. Despite severe tissue disorganization but in line with the intact synaptic organization, the reeler mutation did not affect global metabolic activity of the laminated structures of the brain. CO activity, however, was altered in specific subregions of the cerebellum, hippocampus, and neocortex, as well as in septum and various brainstem (medial pontine, paramedial reticular, paragigantocellular reticular) regions anatomically related to these structures, attesting to large functional alterations in Relnrl-orl brain. Metabolic activity variations were also detected in the ventral tegmental area and ventral neostriatum of the mesolimbic dopaminergic pathway. The results are discussed and compared to the regional CO variations found in other ataxic mice, in regard to the structural defects, the integrity of the connections, and the mutation-specific effects

Neurobehavioral evaluation of Relnrl-orl mutant mice and correlations with cytochrome oxidase activity.

The Reln-rl-orl mutation is characterized by a marked deficit in cerebellar granule cell and Purkinje cell number as well as ectopias in cerebellum, hippocampus, and neocortex. By comparison to Balb/c controls, Reln-rl-orl mutants did not alternate spontaneously in a T-maze and were deficient for visuomotor guidance in a water maze. Despite cerebellar ataxia and motor coordination impairments on stationary beam, coat-hanger, and rotorod tests, the horizontal motor activity of Reln-rl-orl mutants was not reduced in an open-field. The elevated cytochrome oxidase (CO) activity in Purkinje cells and the reduced CO activity in the roof nuclei (interpositus and dentate) of the mutants were associated with poor performance on the small stationary beam. In addition, deficient CO activity of the granular layer of the motor cortex was associated with shorter latencies before falling from the larger stationary beam and a lower number of rears in the open-field. Conversely, elevated CO activity in the polymorphic layer of primary somatosensory cortex was congruent with higher latencies before falling from the same apparatus, indicating functional compensation

Impact of rapid urbanisation and industrialisation on river sediment metal contamination

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Organic carbon, and major and trace element dynamic and fate in a large river subjected to poorly-regulated urban and industrial pressures (Sebou River, Morocco)

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