[en] The N’fis basin located in Tensift region center of Morocco characterized by semi-arid climate, with an area of 2,855 km², in which 60% exceeds an altitude of 1500m. Water resources and exactly groundwater resources were overexploited in N’fis basin and agriculture sector is the most consummate. Water is the key element of socio-economic development. Analysis of the spatial and temporal variations of hydro-climatic series and their trends shows that during the study period (1960-2010) rainfall series, flows and piezometric levels have a downward trend. While temperatures are on an upward trend. And dry years in recent decades are more frequent than wet years. The piezometric level data were subjected to trend (Mann-Kendall), homogeneity (Pettitt rupture test) and linear regression tests. Significant trends were observed. Taking into account the á value of 5% for the N’Fis 3849/53 piezometer (p < 0.0001), -22.96% for Agafay 3595/53 (p < 0.0001) - 6.38% for Tamaslohet 2715/53 (p < 0.0001). 18.42% and for Guemassa 3834/53 (p < 0.0001) 11.38%. On the other hand, the statistical breaks observed for the piezometric levels Agafay, N’Fis, Tamaslohet and Guemassa, (respectively in 2009, 2009, 2006 and 2007) were not all identified in the rainfall series. This means that the evolution of groundwater level in the aquifer also depends on factors other than precipitation. The present study has as a purpose to study and to determine the exact effect of extreme hydrologic situations (drought and floods) on the piezometric level of the aquifer of N’fisHaouz takes into account the other parameters mainly the water exploration for socioeconomic issues. The study concerns the 30 last years.

[en] Full text: Calcium phosphates are essential components in the development of bioactive materials because of their perfect biocompatibility, their ability to bio-degradation and their biological reactivity. In fact, their chemical compositions are similar to the hard tissue of bone and teeth. Besides above biological properties, the Ca-P-based biomaterials found bear osteoinductive ability after processed into special interconnecting porous and specific surface structures (To some extent this structure is inspired from cancellous/spongy bone tissue) [1]. We are now developing work on essentially two types of these materials as bone substitutes: bioceramics based on hydroxyapatite and tricalcium phosphate from natural substances abundant in the country. We are interested in the synthesis of a macroporous calcium phosphate-carbonated apatite. It is for its biological properties, its availability and low cost as well as its physico-chemical. In our work, we use the microwave-hydrothermal method, which enables to synthesize the ultra fine and high purity powders for shortening working time. This method has some advantages such as heating throughout the media, rapid heating, fast reaction, high yield, excellent reproducibility, narrow particle distribution, high purity and high efficient energy transformation , and being environmentally cleaner. The physical and chemical analyses were carried out on the dried precipitate and the powder calcined at 900 degree. The phases formed were identified by the time of heating in microwave, determined by infrared spectroscopy and by X-ray diffraction. The software used for data processing of X-ray diffraction was DIFFRACT-AT.

[en] In this work, we have turn to account the radiochemical techniques in order to investigate the complexation of Cd sup 2 sup +, U(O sub 2) sup 2 sup + and Th sup 2 sup +, at strength Mu=0,2, in various phosphoric media characterized by C sub ( H sub 3 P O sub 4) <= 4 M and 0.7 <= pH <= 4. The method chosen for this purpose is the liquid-liquid extraction of radioisotopes at tracer scale, with di(2-ethyl hexyl) phosphoric acid dissolved in benzene. The radionuclides used are Cd-109, U-233, U-230 and Th-227. Their distribution between the two phases are established by alpha or gamma spectrometric analysis. The analysis of the distribution data allows to define, in addition of species extracted in organic phase, the nature of phosphoric complexes which take place in aqueous media. Stability constants of these complexes and associated thermodynamic data are determined. 2 tabs.; 2 refs. (author)

[en] The present study evaluates the distribution of metals over the last 100 years in the Oualidia lagoon by examining their concentrations in the sediment cores. The samples were analyzed by instrumental neutron activation analysis and inductively coupled plasma mass spectrometry. Activities of 210Pb, 226Ra, and 137Cs were determined by gamma-ray spectrometry for establishing the age-depth relationships throughout the sediment cores by applying conventional models. The results indicated that the study area is contaminated by As and Cd revealing a detectable anthropogenic input of occurring metals as a consequence of the continuous development of human activities around the lagoon since 1950. The enrichment factor calculated for each layer of the three cores revealed that the studied sediments present no enrichment by Pb, K, and Mn; minor enrichment by Zn, Cr, Co, Cu, V, and Ni; and a moderately to severe enrichment by As and Cd. The pollution load index values increase from the bottom to the top of cores, and ranged from 0.9 to 2.8, which indicates levels of pollutants ranging from background to relatively high concentrations in the investigated sediments. (author)

[en] The photochromic behavior of two newly synthesized diarylethenes is here presented. The compounds studied are the symmetrical (1-benzyl-3,4-bis(2-methylbenzo[b]thiophen-3-yl)-[1H]-2,5-dihydropyrrol-2, 5-dione) and the unsymmetrical (1-benzyl-3-(2-methylbenzo[b]thiophen-3-yl)-4-(2,5-dimethyl-3-thienyl)-[1H] -2,5-dihydropyrrol-2,5-dione). Upon stimulation with UV or violet light, these compounds become red-colored due to photocyclization and cyclorevert to the light yellow open form upon irradiation with visible light. In this work, absorption and fluorescence spectra, molar absorption coefficients of the ethenic and cyclized forms, fluorescence quantum yields and photochemical quantum yields of both the forward and back photoreactions were determined. Temperature, excitation wavelength and solvent effects were explored. The symmetrical compound was found to be a bistable photochrome. In contrast, the unsymmetrical molecule resulted unsuitable as photochrome because of side degradation processes occurring in competition with cyclization.

[en] Phosphate rocks can contain considerable amounts of accompanying uranium and rare earth elements (REEs). Interest to extract these elements during phosphate rock processing to mineral fertilizer is given as both uranium and REEs are valuable and toxic. Recovering these elements is thus advantages from a resource conserving and environmental protection point of view. Past efforts to recover uranium and REEs focused on extracting these elements from the intermediate products (phosphoric acid and phosphogypsum) during de-hydrate wet phosphoric acid production. Another approach, that is discussed here, is direct leaching of uranium and REEs from phosphate rocks before phosphate rock processing. First successful lab scale experiments with a selected leaching reagent and phosphate rock from the Abu Tartur mine in Egypt are presented and discussed. (paper)

[en] Highlights: • The Sidi Moussa lagoon, located near the biggest phosphate processing plants in the world, is contaminated by some metals and radionuclides. • The agricultural activities and North-West African upwelling contribute to sediment contamination. • Results have revealed the positive effects of the environmental management system adopted by The Moroccan Phosphate Company. The Sidi Moussa lagoon, located in western coastal Morocco and ranked as a wetland of biological and ecological importance (Ramsar site), is contaminated due to its proximity to the industrial phosphate plants and other anthropogenic activities around it. This study was carried out to assess the current environmental state of the lagoon as well as historical inputs of pollutants over several decades. Three sediment cores were collected and analyzed for the determination radionuclide activities (²¹⁰Pb, ²²⁶Ra, ²³⁸U and ¹³⁷Cs) by gamma spectrometry and element concentrations by Inductively Coupled Plasma – Mass Spectrometry. Age-depth relationships were established in two cores using ²¹⁰Pb and ¹³⁷Cs as chronometer and time-marker, respectively, and Constant Rate of Supply as radiometric dating model. ²¹⁰Pb and ²³⁸U were present in sediment in activities much higher than those reported for non-contaminated coastal systems. Sediment accumulation rates showed a slight increase over time with a depth-averaged value of 0.16 g cm⁻² y⁻¹. Enrichment Factors and practically derived sediment quality guidelines were used to assess sediment contamination/pollution and toxicological effects linked with the measured concentrations of sediment-bound elements. The profiles of Cr, Co, Cu, As and Ni displayed maximums at depths matching the start of the phosphate industrial plants, and decreasing concentrations in the sections above the maximums, revealing the positive effects of the environmental management system adopted by the phosphate company since early 2000s.

[en] Prevention of possible noxious effects in relation with the exposure to one or several chemical, physical or biological agents present in our domestic or professional environment is one of today's big public health stakes. Another stake is the better assessment of the risks linked with the use of health-care products. The efficacy and predictiveness of toxicology studies are directly related to the combination of alternate complementary methods and animal experiments (obtaining data from different species and with different models: in vitro, ex vivo and in vivo). Despite important efforts, the toxicological evaluation remains perfectible. The proceedings of this 2010 congress of the French Society of cell pharmaco-toxicology deal with recent advances, both scientific and technological, in 'predictive toxicology'. Four main topics are approached: cell and organ models, 'omics', in silico modeling, and new technologies (imaging, cell ships, high-speed processing). Among the different presentations, 3 abstracts present some recent advances in imaging techniques applied to toxicology studies. These are: 1 - first uses in toxicology of TOF-SIMS mass spectroscopy imaging (O. Laprevote, Paris-Descartes Univ. (FR)); 2 - Small animal imaging, a tool for predictive toxicology (A. Le Pape, CNRS Orleans (FR)); 3 - uranium localization at cell level using SIMS imaging technique (C. Rouas et al., IRSN Fontenay-aux-Roses (FR)). (J.S.)