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Accueil > Thèses et stages > Thèses soutenues

2014

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FAJRAOUI Noura
"Éléments finis stochastiques spectraux (SSFEM). Application aux transferts en milieu poreux."
21 janvier 2014 - dir. A. Younes

GONTIER Adrien
"Modélisation de l’influence du changement climatique sur la nappe phréatique du Rhin Supérieur."
18 juillet 2014 - dir. F. Chabaux

LECLUSE Simon
"Modélisation de l’influence du changement climatique sur la nappe phréatique du Rhin Supérieur."
16 janvier 2014 - dir. P. Ackerer

LEFRANCQ Marie
"Transport and attenuation of pesticides in runoff from agricultural headwater catchments : from field characterisation to modeling." english viva
11 avril 2014 - dir. G. Imfeld
abstract
Understanding the transport and attenuation of pesticides is crucial to evaluate their ecological impact on non-target ecosystems. Current knowledge on the spatial variability of pesticide deposition during application, the impact of erosion on pesticides export, and the extent of pesticide degradation in runoff is very limited at the agricultural headwater catchment scale. In this thesis, field investigations and numerical modeling at two elemental scales, i.e. the plot and catchment, were combined to address these remaining issues in two different agricultural contexts. A mathematical formalism was developed to predict pesticide mobilisation and transport in runoff and was integrated in LISEM (LImbourg Soil Erosion Model).
The results show that (i) non-target areas such as impermeable roads contributed to more than 40% to the overall load of runoff-associated fungicides exported from the vineyard. (ii) Pesticide partitioning between suspended solids and runoff water differed largely according to the molecules and the hydrological dynamics. (iii) The occurrence of degradation products and the enrichment of the R-metolachlor were observed in soil, suspended solids and runoff water suggesting the potential of enantiomer analyses for assessing biodegradation of chiral pesticides at such scale. Overall, the investigation demonstrated that combining different approaches at the catchment scale enable a better understanding of pesticide transport and attenuation.

MAILLARD Elodie
"Transport and Degradation of Pesticides in Wetland Systems :
A Downscaling Approach." english viva
14 mars 2014 - dir. G. Imfeld
abstract
A mechanistic understanding of transport and degradation processes of modern agricultural pesticides, including chiral pesticides, is critical for predicting their fate in the environment. In agricultural landscapes, wetlands can intercept pesticide-contaminated runoff or groundwater and improve water quality through various retention and degradation processes. Quantitative knowledge on pesticide partitioning, distribution and degradation in the different wetland compartments in relation to biogeochemical and hydrological conditions is currently limited. In a downscaling approach, three different wetlands, i.e. a stormwater wetland (320 m2), subsurface-flow constructed wetlands (7 m2) and lab-scale wetlands (0.02 m2) receiving agricultural runoff were used as ‘natural laboratories’ to investigate the fate of widely used pesticides.
Overall, our results showed that dynamics of hydrological and redox conditions largely influenced pesticide sorption mechanisms and their distribution
over time within wetland compartments, thereby controlling degradation processes. While large-scale studies provide integrative information on pesticide dissipation and distribution patterns with respect to wetland functioning, small-scale investigations using novel methods such as isotope and enantiomer analyses characterize underlying molecular processes governing pesticide degradation.

PAYRAUDEAU Sylvain - HDR
"Impact of hydro-climatic forcing on contaminant transport in agrosystems - Transport de contaminants dans les agrosystèmes vis-à-vis du forçage hydro-climatique." english viva
15 septembre 2014 - garant d’habilitation : P. Ackerer

SCHMITT Anne Désirée - HDR
"Le cycle biogéochimique du Ca : apport des isotopes du Ca ."
23 septembre 2014 - garant d’habilitation : P. Stille

TROTTIER Nicolas
"Modélisation des écoulements en milieux poreux fracturés : estimation
des paramètres par approche inverse multi-échelle."
16 mai 2014 - dir. P. Ackerer