Éditeur(s) : GFP : Groupe Français des Pesticides GFP : Groupe Français des Pesticides GFP : Groupe Français des Pesticides
Extrait de : "Protection des cultures et santé environnementale : héritages et conceptions nouvelles" : congrès, le 26 mai 2014. Université des Antilles et de la Guyane
Résumé : Les pouvoirs publics doivent faire face à la pollution des sols et des ressources en eau, par un pesticide organochloré (la chlordécone). La forte rétention de ce pesticide dans les sols volcaniques et la microstructure peu accessible des allophanes conduit au constat qu'il sera difficile de dépolluer les sols par des techniques classiques (chimiques, phytoremédiation ou biodégradation) déjà peu adaptée à cette molécule persistante. Nous proposons donc une alternative à la dépollution : la séquestration des pesticides. L'objectif est de favoriser le piégeage des pesticides dans le sol en incorporant de la matière organique (MO). Les résultats obtenus démontrent l'efficacité du procédé avec des transferts sol/eau et sol/plantes fortement diminués grâce à l'ajout de MO.
Les pouvoirs publics doivent faire face à la pollution des sols et des ressources en eau, par un pesticide organochloré (la chlordécone). La forte rétention de ce pesticide dans les sols volcaniques et la microstructure peu accessible des allophanes conduit au constat qu'il sera difficile de dépolluer les sols par des techniques classiques (chimiques, phytoremédiation ou biodégradation) déjà peu adaptée à cette molécule persistante. Nous proposons donc une alternative à la dépollution : la séquestration des pesticides. L'objectif est de favoriser le piégeage des pesticides dans le sol en incorporant de la matière organique (MO). Les résultats obtenus démontrent l'efficacité du procédé avec des transferts sol/eau et sol/plantes fortement diminués grâce à l'ajout de MO.
Siècle(s) traité(s) : 21
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V14252
V14252
V14252
V14252

Éditeur(s) : HAL CCSD
Résumé : The geological storage of CO 2 is considered as one of the solutions to the problem of global warming. The most possible scenarios of geological behavior of soil in the long term conditions has to be precisely defined to avoid catastrophic damages in the future. Chemical properties of saline water in the aquifer after the CO 2 injection becomes more acidic with time. Therefore, chemical degradation of rock occurs, which leads to modifications of its mechanical properties (chemo-mechanical coupling) [1]. In this paper an incremental model of chemo-mechanical coupling using homogenization approach (asymptotic expansion method [2,3]) is proposed. The paper is focused on the numerical computations for the X-ray tomography image of carbonate rock microstructure [4]. The chemical degradation of the microstructure is obtained as a homogeneous dissolution in each direction (Fig.1. – Fig.2.) For every porosity state numerical computations to obtain full, orthotropic elasticity tensor are performed. Therefore, the degradations functions for all components of the rigidity tensor were defined (Fig.3.). Moreover, results of numerical calculations of diffusion, tortuosity and permeability tensors are presented [5,6]. The link between geometrical properties and mechanical and transport parameters are discussed. The numerical analysis of the carbonate rock sample in long term conditions shows the increase of porosity and associated mechanical weakening of the rock. Moreover, the increase of diffusion, tortuosity and permeability tensors elements with time were observed. Finally, the solution of the one-dimensional macroscopic problem of soil settlement due to chemical dissolution of rock at constant load is presented. The method is universal, in the sense that the non-dimensional time scale is used.
ALERT Workshop 2013
Aussois, France

hal-01103175
https://hal.archives-ouvertes.fr/hal-01103175

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The subcontinental lithospheric mantle evolves through time due to tectonic events and processes as static recrystallization and melt percolation. To constrain the extent of these processes in the South Patagonian subcontinental mantle lithosphere we performed a microstructural and Electron Backscattered Diffraction (EBSD) study of a suite of 35 peridotite xenoliths brought to the surface by Plio-Pleistocene alkaline volcanic rocks from Gobernador Gregores and Pali Aike. All samples show a well-developed olivine and pyroxene crystallographic preferred orientation (CPO), consistent with deformation by dislocation creep with dominant activation of [100]{0kl} in olivine. The coarse granular or tabular textures and the low density of intracrystalline deformation features indicate that deformation was followed by annealing under static conditions. The xenoliths also show microstructural evidence of multiple episodes of reactive melt percolation. Neither annealing nor melt percolation erased the olivine CPO, which has [010]-fiber, [100]-fiber and orthorhombic patterns in Pali Aike xenoliths and essentially [010]-fiber and orthorhombic patterns in Gobernador Gregores xenoliths. Seismic properties calculated based on the CPO and modal compositions are, however, rather homogeneous, with fast S-wave polarization and P-wave propagation parallel to the [100] olivine axis. The variation in the olivine CPO solely changes the minimum S-wave birefringence direction, which is normal to the foliation for axial-[010] olivine CPO. Average samples for the two localities, obtained by adding up the individual samples CPO data in a common reference frame, show, however, a 'normal' upper mantle anisotropy with a maximum S-wave birrenfringence of ca. 5% at high angle to the both the maximum [010] and [100] axes concentrations, that is in the foliation, but normal to the lineation, and a minimum birefringence at low angle to the [100] maximum, that is parallel to the lineation.
ISSN: 0040-1951

hal-01053500
https://hal.archives-ouvertes.fr/hal-01053500
DOI : 10.1016/j.tecto.2014.02.017