The purpose of this research is to develop a direct spectrometric approach to monitor soils and waters, at a lower cost than the widely used chromatographic techniques; a spectrometric approach that ...is effective, reliable, fast, easy to implement, and without any use of organic solvents whose utilization is subject to law limitation. It could be suitable at least as an alert method in case of massive contamination. Here, we present for the first time a catalog of excitation–emission and total synchronous fluorescence maps that may be considered as fingerprints of a series of homologated pesticides, in large use in Morocco, aiming at a direct detection of their remains in agricultural soils and neighboring waters. After a large survey among farmers, agricultural workers and product distributors in two important agricultural regions of Morocco (Doukkala-Abda and Sebou basin), 48 commercial pesticides, which are fluorescent, were chosen. A multi-component spectral database of these targeted commercial pesticides was elaborated. For each pesticide, dissolved in water at the lowest concentration giving a no-noise fluorescence spectrum, the total excitation-emission matrix (TEEM), the total synchronous fluorescence matrix (TSFM) in addition to synchronous fluorescence spectra (SFS) at those offsets giving the highest fluorescence intensity were recorded. To test this preliminary multi-component database, two real soil samples, collected at a wheat field and at a vine field in the region of Doukkala, were analyzed. Remains of the commercial Pirimor (Carbamate) and Atlantis (Sulfonylurea) were identified by comparison of the recorded TEEM, TSFM, and SFS to those of the preliminary catalog at one hand, and on the basis of the results of a field pre-survey. The developed approach seems satisfactory, and the fluorimetric fingerprint database is under extension to a higher number of fluorescent pesticides in common use among the Moroccan agricultural regions.
Concentrations of Al, Fe, Cr, Cu, Ni, Pb and Zn in soils, sediments and water samples collected along the Oued Boufekrane river (Meknes, central Morocco) were determined. In soils, a homogeneous ...distribution of metal concentrations was observed throughout the study area except for Pb, which presents high enrichment at sites located at the vicinity of a main highway. In sediments, high enrichment, with respect to upstream sites, were observed downstream of the city of Meknes for Al, Cr, Fe and Ni and inside the city for Cu, Zn and Pb. In water samples, the metal contents showed to correlate with their homologues in sediments suggesting that the metal contents in water and sediments have identical origins. Descriptive statistics and multivariate analysis (principal factor method, PFM) were used to assist the interpretation of elemental data. This allowed the determination of the correlations between the metals and the identification of three main factor loadings controlling the metal variability in soils and sediments.
The k0-method of neutron activation analysis (k0-NAA) was used in order to determine the concentration of major and trace elements in sediment samples collected from different sites in the Gharb ...plain along the Sebou River (Morocco). Samples have been analyzed using neutrons of the Moroccan Triga Mark II research reactor. Two types of irradiation (short and long) have been carried out using the Pneumatic Tube System (PTS) and the Rotary Specimen Rack (RSR). Acquisition and Fitting of spectra have been carried out by Maestro software and k0-IAEA program respectively. Pollution indicators (enrichment factor (EF), geoaccumulation index (Igeo), contamination factor (CF) and pollution load index (PLI)) were calculated to assess the pollution status of the sediments. Results of pollution indices showed no contamination all around the catchment area except for the stations (MS1 and MS2) located downstream the Sebou river. Principal component analysis (PCA) was carried out with the Pearson coefficient in order to determine possible relationships between major and trace elements. The comparison with other subsequent studies on Sebou river gives an idea about the temporal evolution of heavy metal contamination at national scale.
KeV-MeV ion irradiation of polyvinylidene fluoride (PVDF) films Torrisi, L.; Ciavola, G.; Percolla, R. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
08/1996, Letnik:
116, Številka:
1
Journal Article
Recenzirano
Semicrystalline polyvinylidene fluoride (PVDF) films have been irradited with different ion beams and energies ranging between 0.1 keV/amu and 6 MeV/amu. Polymer modifications induced by the ion ...irradiation, for electronic and nuclear energy stopping, have been investigated in situ by a highly sensitive quadrupole mass spectrometer. Ion irradiation of PVDF produced ejection of H
2 and HF molecules with a high chemical yield. Switching on the ion beam, the measured yields show a prompt (for H
2) and a slow (for HF) component of the molecular emission, which depends on the ion energy, ion fluence and polymer temperature. Along the ion track, the energy deposition produces a high density of active species, which give rise to desorbed molecules, to cross-linking processes and to a very stable residual carboneous film. At room temperature, the diffusion coefficient of HF molecules measured in irradiated PVDF is of the order of 10
−8 cm
2/s. The structural modifications of the irradiated films have been investigated ex situ by X-ray diffraction and optical absorption. The ion energy deposition along the ion track can be useful to realize active bio-membranes through the polymer grafting process.
Elemental analyses of sediments from the barrage El-Kansera on the river Oued Beht in Morocco, are reported. These analyses were performed by means of proton induced X-ray emission (PIXE), and ...Rutherford backscattering spectroscopy (RBS). The RBS analysis allowed the determination of the sediments matrix composition, which was used for the PIXE analysis. The quantitative analyses of the PIXE spectra were performed by using the binary encounter approximation (BEA) for the inner shell ionization cross section. Preliminary results are presented, and a comparison with literature data is discussed.
PIXE and XRF comparison for applications to sediments analysis Benyaïch, F.; Makhtari, A.; Torrisi, L. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
11/1997, Letnik:
132, Številka:
3
Journal Article
Recenzirano
The potential of particle induced X-ray emission (PIXE) and X-ray fluorescence (XRF) is compared with regard to its application to sediments analysis. The intrinsic features of each of the two ...techniques are addressed, and their elemental sensitivities are evaluated and compared, showing that in the case of sediments analysis, due to the complexity of their composition, the two techniques are complementary.
It is shown that both the kinetics and the mode of realignment of As doped polysilicon films deposited onto crystalline silicon substrates, strongly depend on the morphology of the interfacial native ...oxide film. During rapid thermal annealing the as deposited and doped polycrystalline layers realign via the lateral growth of large epitaxial columns in a way similar to secondary recrystallization. In layers submitted to a high temperature anneal before the As implantation, the realignment occurs by the planar motion of the whole interface towards the surface of the layers, and can be achieved at low annealing temperatures and for short times, with a reduced redistribution of the dopant atoms.
X-irradiated samples of P
2O
5A
2WO
4A
2O (A = Li, Na) glasses were studied by electron paramagnetic resonance (EPR) at X-band (9.5 GHz). Modifications of the EPR spectra are observed following in ...situ the sample's temperature or after thermal annealing. The spectra analysis was carried out by computer simulations specifically adapted for glasses in which statistical distributions are introduced for some EPR parameters. Three signals were detected: a hyperfine structure (doublet) which was assigned to a PO
4
2− center, and two anisotropic signals attributed to the peroxy radicals.
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