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Dakar, Senegal

The paleoenvironnementals studies realized during the Paleocene to Miocene epoch indicate variables sea surface temperatures and lagoons in the Casamance sub-basin. Paleocene and Eocene transgressions provided food and install a low oxygen zone. Detrended correspondence analysis (DCA) realized with benthic foraminifera associations from three boreholes indicates important diversity of genera Lenticulina, Eponides, Cibicidoides, Uvigerina and Baggina on the carbonate slope. Sea surface temperatures increase during the Lutetian and coincide with the development of genera Nonion and Operculina. Oligocene regression installs in the western part of the Basin a cold hyposaline epicontinental sea dominated by the genera Ammonia, Textularia, Spiroplectammina, Elphidium and Planulina. Miocene benthic fauna is dominated by the genera Cibicides, Hopkinsina, Bolivina, Nonion, Uvigerina and Bulumina which evolve in an hyposaline to normal epicontinental sea. Source

Mbaye O.M.A.,University of Marne-la-Vallee | Mbaye O.M.A.,University op | Gaye Seye M.D.,University of Marne-la-Vallee | Gaye Seye M.D.,University op | And 5 more authors.
Microchemical Journal | Year: 2013

The photo-induced fluorescence (PIF) spectral properties of propanil, a contact anilide herbicide were investigated. In the PIF approach, non-fluorescent propanil was transformed by UV irradiation into strongly fluorescent photo-product(s). The effect of solvents, including water, methanol, methanol-water binary mixtures and cyclohexane, on the propanil PIF properties was studied, and several PIF parameters (irradiation time, excitation and emission wavelengths, medium) were optimized. As a result, the analytical usefulness of a simple, sensitive and precise PIF analytical method was demonstrated for the determination of propanil. The best PIF analytical performances were obtained in an 80/20% v:v methanol/water mixture, with a wide linear dynamic range (LDR) of nearly three orders of magnitude, low limit of detection (LOD) and limit of quantification (LOQ) values of, respectively, 1.3 and 4.7ngmL-1, and a small relative standard deviation (RSD) of 1.3%. The optimized PIF method was applied to the estimation of propanil residues in various spiked natural water samples, collected in the Senegal River valley, with satisfactory recovery percentage values (97-117%). An interference study of several foreign species, including pesticides and inorganic ions, likely to be present in the Senegal natural waters, was also performed. © 2013 Elsevier B.V. Source

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