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).

An annual-basis study of the impacts of the anthropogenic inputs from Fez urban area on the water geochemistry of the Sebou and Fez Rivers was conducted mostly focusing on base flow conditions, in addition to the sampling of industrial wastewater characteristic of the various pressures in the studied environment. The measured trace metals dissolved/particulate partitioning was compared to the ones predicted using the WHAM-VII chemical speciation code. The Sebou River, upstream from Fez city, showed a weakly polluted status. Contrarily, high levels of major ions, organic carbon and trace metals were encountered in the Fez River and the Sebou River downstream the Fez inputs, due to the discharge of urban and industrial untreated and hugely polluted wastewaters. Trace metals were especially enriched in particles with levels even exceeding those recorded in surface sediments. The first group of elements (Al, Fe, Mn, Ti, U and V) showed strong inter-relationships, impoverishment in Fez particles/sediments and stable partition coefficient (Kd), linked to their lithogenic origin from Sebou watershed erosion. Conversely, most of the studied trace metals/metalloids, originated from anthropogenic sources, underwent significant changes of Kd and behaved non-conservatively in the Sebou/Fez water mixing. Dissolved/particulate partitioning was correctly assessed by WHAM-VII modeling for Cu, Pb and Zn, depicting significant differences in chemical speciation in the Fez River when compared to that in the Sebou River. The results of this study demonstrated that a lack of compliance in environmental regulations certainly explained this poor status.

Impact of rapid urbanisation and industrialisation on river sediment metal contamination.

This study aimed at evidencing contaminant inputs from a rapidly growing population and the accompanying anthropogenic activities to river sediments. The Fez metropolitan area and its impacts on the Sebou's sediments (the main Moroccan river) were chosen as a case study. The Fez agglomeration is surrounded by the river Fez, receiving the wastewaters of this developing city and then flowing into the Sebou. The sediment cores from the Fez and Sebou Rivers were extracted and analysed for major elements, butyltins and toxic metals. Normalised enrichment factors and geoaccumulation index were calculated. Toxicity risk was assessed by two sets of sediment quality guideline (SQG) indices. 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 in upstream of Fez city, whilst the Fez' sediments were heavily polluted and exhibited bottom-up accumulation trends, which is a clear signature of recent inputs from the untreated wastewaters of Fez city. Consequently, the sediments of Fez and Sebou at the downstream of the confluence were found to be potentially toxic, according to the SQG levels. This finding is concerned with aquatic organisms, as well as to the riverside population, which is certainly exposed to these pollutants through the daily use of water. This study suggests that although Morocco has adopted environmental regulations aiming at restricting pollutant discharges into the natural ecosystems, such regulations are neither well respected by the main polluters nor efficiently enforced by the authorities.

A synthetic aragonite-based bioceramic: influence of process parameters on porosity and compressive strength.

We investigate the influence of process parameters such as weight fraction and particle size of pore-former, and isostatic pressure, on porosity and compressive strength of non-sintered porous calcium carbonate biomaterials compacted at high pressure in uniaxial or isostatic mode. Experiment design and results analysis are performed according to a two-level 2k factorial design method (FDM). Results indicate that only the weight fraction of pore-former (wt fpf) influences significantly the porosity and the compressive strength. The porosity P, is described by a linear function of wt fpf, and the compressive strength sigma(comp), by an exponential one. For materials compacted under uniaxial pressing: P (vol%) = 33.7 + 85.4 (wt fpf) and sigma(comp) (MPa) = 28.8e(-9.2(wt fpf)) with 0.1 < or = wt fpf < or = 0.3. For materials compacted in isostatic mode: P (vol%) = 33.9 + 82.1 (wt fpf) and sigma(comp) (MPa) = 24.0e(-7.0(wt fpf)) with 0.15 < or = wt fpf < or = 0.35. The pore-former particle size has no significant influence on both properties. The increase in isostatic pressure provides slightly lower porosity and better compressive strength. For a fixed fraction of pore-former, isostatic pressing leads to a better compressive strength than uniaxial pressing. This study indicates that, for a constant amount of pore former, the size of macropores can be adjusted to reach optimal bone-ingrowth without change in compressive strength.

[Intraspinal neuro-enteric cyst without associated abnormalities. Apropos of a case]. / Kystes neuro-entériques intra-rachidiens sans malformation associée. A propos d'un cas.

The authors report a case of dorsal extramedullary neuro enteric cyst without any associated dysraphic lesion. The clinical and radiological aspects are presented. Discussions on the embryogenesis and pathogenesis of this rare lesion are reviewed.

Cerebral aspergillosis and encephalomeningocele.

A case of massive cerebral aspergillosis complicating a frontal encephalomeningocele is reported. The etiology and pathogenesis are discussed and the diagnosis, symptoms, and treatment possibilities reviewed.

[So-called benign intracranial hypertension and Behçet's disease]. / Hypertension intracrânienne dite "bénigne" et maladie de Behcet.

Five cases of Behcet's disease with pseudo-tumor cerebri are reported and discussed. The authors put the emphasis on three main points : - this morbid association is not rare; - it explains the hypothesis suggested that pseudo-tumor cerebri is secondary to the alteration of intracranial venous system and CSF resorption disturbance; - the visual prognosis is poor in this entity.

[Optochiasmatic diastasis in tumors with suprasellar extension and duplication of the chiasma]. / Le diastasis opto-chiasmatique dans les tumeurs à extension supra-sellaire avec duplication du chiasma.

The opto chiasmatic diastasis whose extreme form is a duplication of the chiasma, corresponds to a longitudinal cleavage, using the well known fasciculation of the optic fibres. It has been noticed four times in the sellar and para sellar expanding processes (two adenomas, one craniopharyngioma and one metastasis). Generally, this lesion of the chiasma goes with big tumors (grade II); it has been detected four times in frontal approaches (15%) while the rhinoseptal approach represents 85% of our cases. The diastasis of the optic fibers with tendency to form double chiasma, instead of being an exception, happens in 4% of sellars tumors. It is perfectly identified by the frontal surgical approach, but is really hard or impossible to be recognized by the rhinoseptal surgical way. The mechanisms and the prognosis of this lesion are discussed.

[Contribution of Doppler angiography to the study of sub-millimeter cortical arteries]. / Apport du Doppler per-opératoire dans l'étude des artères corticales sub-millimétriques.

Intra operative Doppler has been already used especially during cerebral vascular malformations surgery. The systematic practice of this method, in 15 cases, for the blood flow study of the sub millimetric cortical vessels is helpful, very simple, and harmless. The investigation has been achieved by the direct application of a sterilized 8 MHZ, 5 mm Doppler probe on a small cortical artery. As the diameter has been exactly measured (0,8 mm +/- 0,2 in 15 cases) it is easy to calculate the blood flow from the recorded curve diagrams. The normal cortical flow of the sub millimetric arteries is about 2,52 cm3/mn +/- 1,16 confirming the previous data obtained with other methods of approach. The study of contused brains, points out, the disastrous effect of edema on cerebral blood flow, which before a complete arrest, looses its continuous diastolic pattern. Deep seated angiomas can be accurately located together with the flow direction in their feeding vessels. This method is also of fair interest for extra intra-crânial anastomosis, the choice of the cortical artery for bypass and its functional appreciation.