Baran, Nicole

Girardeau, Benjamin

Sidoli, Pauline

English

Archive Ouverte en Sciences de l'Information et de la Communication

HAL Id: hal-01719471
https://hal-brgm.archives-ouvertes.fr/hal-01719471
Submitted on 28 Feb 2018
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Chiral signatures of herbicides and metabolites
concentrations as tools to characterize the
hydrodynamic of aquifer
Nicole Baran, Benjamin Girardeau, Pauline Sidoli
To cite this version:
Nicole Baran, Benjamin Girardeau, Pauline Sidoli. Chiral signatures of herbicides and metabolites
concentrations as tools to characterize the hydrodynamic of aquifer. EGU - European Geosciences
Union General Assembly 2018, Apr 2018, Vienne, Austria. ￿hal-01719471￿
Geophysical Research Abstracts
Vol. 20, EGU2018-9915, 2018
EGU General Assembly 2018
© Author(s) 2018. CC Attribution 4.0 license.
Chiral signatures of herbicides and metabolites concentrations as tools to
characterize the hydrodynamic of aquifer
Nicole Baran, Benjamin Girardeau, and Pauline Sidoli
BRGM, ORLEANS, France (n.baran@brgm.fr)
Increasing surveillances demonstrated the presence of pesticides and their metabolites in surface and groundwater,
sometimes at concentrations higher than the threshold values admitted. The implementation of programs of
measures to improve the groundwater quality may sometimes seem to be ineffective as transfer times of water and
solutes are long. Constraining this timeframe between the implementation of measures and the impact on water
quality is thus a key point to evaluate the effectiveness of measures.
Many pesticides are chiral. Since some isomers are inactive, plant protection producers try to develop market
products with active isomer enrichment in order to decrease the rate of application and as a consequence the impact
on water quality. In this context of drastic switch from one chiral form to the other, the use of the chiral ratio
of a pesticide appears as a promising tool to characterize the infiltration rate of water from soil to groundwater.
However, in order to validate this tool, it is necessary to characterize the evolution of chiral signatures during the
degradation process. In that perspective, the more the signature will be conservative, the more the tool will be
efficient.
Determining the areas where the infiltration of water is the highest in a catchment is also important for the
implementation of programs of measures. Metabolites of pesticides are in many cases very mobile compounds
prone to be easily leached into groundwater. Monitoring these metabolites is also useful to better constraint the
hydrodynamic functioning of an aquifer. Data on the kinetics of apparition and the kinetics of dissipation of these
metabolites are scarce. However, these data are crucial to determine when and how long they can potentially be
leached.
Here we present new data based on the determination of chiral signatures of two selected herbicides (metolachlor
and dimethenamid). We conducted degradation experiments on 2 different soils using both racemic and isomer
enriched molecules. During these experiments, the fate of their metabolites was also characterized. The results
allow defining the potentialities of these tools, namely the use of chiral signature and the metabolite occurrence,
in the goal of improving the knowledge of aquifer functioning.


Chiral signatures of herbicides and metabolites concentrations as tools to characterize the hydrodynamic of aquifer

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Chiral signatures of herbicides and metabolites concentrations as tools to characterize the hydrodynamic of aquifer

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