Qu’est-ce qui pollue les cours d’eau français ?

THE CONVERSATIO

APPORTS ET TRANSFERT DE PESTICIDES EN MILIEUX AGRICOLE ET URBAIN DANS LE BASSIN VERSANT DE LA MARNE (VERS UNE EVALUATION GLOBALE)

MARNE-LA-VALLEE-ENPC-BIBL. (774682303) / SudocSudocFranceF

La qualité de l’eau en agglomération parisienne, un défi de taille

INSU CNRS/CNRSINFO.F

Determination of glyphosate and AMPA in fish bile from the Marne River, France

International audienceGlyphosate is a widely used herbicide. In France, it is used during intercultural operations and to control weeds in non-agricultural areas. Glyphosate and AMPA (its main degradation product) can reach high concentrations in rivers, especially in the Seine basin including the Paris suburb (France). Although it is not bioaccumulative, the associated use of surfactants in pesticide formulations allows better assimilation in biological tissues. The aim of our study was first to develop a method to assess glyphosate and AMPA levels in biological tissues and then to determine the contamination of an freshwater fish, the European chub (Squalius cephalus) by glyphosate and AMPA. Fish were fished in the Marne River (a tributary of the Seine River situated in the East part of Paris) at 4 sites characteristic of agricultural and urban areas. Water was also sampled for analysis to compare sites contamination. Bile is an ideal material to identify metabolites of pollutants. This biological fluid was taken directly from the gallbladder with a syringe on freshly euthanized chub and frozen for further analysis. Then, 100μL of bile was taken and 500μL of internal standard (13C-Glyphosate and 13C-AMPA) were added before extraction with milliQ water (5mL) and ultrasonic method for 30 minutes. The extract was then derivatizated (FMOC-Cl) and concentrated on SPE OASIS HLB cartridge (60cc) before LC MS MS analysis. Preliminary tests were performed to establish and validate the protocol and to find the lowest limit of quantification and the best reproducibility. Results showed that glyphosate is detected in a fish sample coming from the most contaminated site by AMPA. This suggests that glyphosate is assimilated in fish and is still detectable after glyphosate has been degraded to AMPA in the water river. Glyphosate content in fish could be an indicator of environmental contamination. Further developments are needed to validate the protocol and complete the study with other organs than bile

Suivi à long terme des pesticides pour la compréhension de leurs processus de transfert à l'échelle du bassin versant

RA PIREN SeineLe suivi en continu de la contamination par les pesticides dans le bassin versant de l’Orgeval a été initié en 2008. Ainsi, 10 ans de données sont maintenant disponibles afin de voir leur comportement sur le long terme et permettre de confronter les résultats de simulation des modèles. Les prélèvements ponctuels ne sont souvent pas pertinents pour la comparaison avec des sorties de modèle car les concentrations sont très fluctuantes dans le temps, surtout dans un petit cours d’eau comme l’Orgeval. Ici, les prélèvements sont asservis au débit et moyennés mensuellement. Un focus est fait ici pour les molécules emblématiques pour lesquelles la tendance d’évolution peut être directement mise en relation avec la dynamique des usages phytosanitaire

Apport d'une modélisation couplée hydrogéologique et biogéochimique pour caractériser la contamination par les pesticides des masses d'eau du bassin Seine-Normandie

International audienc

Nouvelles contaminations par les pesticides et leur utilisation comme traceur des masses d'eau

PIREN-Seine phase 8 -Rapport 2022The pesticide monitoring in the Orgeval catchment (France) was initiated in 2008 in order to understand the long-term fate of pesticides and to validate the transfer model developed within the framework of PIREN-Seine. Thus, 12 years of contamination data are now available for a list of molecules that is still evolving according to new uses. At the same time, past phytosanitary practices were determined in the basin. The assessments of current uses are extracted from the BNV-D for the Seine-et-Marne department. A focus is made on the emblematic substances for which the evolution trend can be directly related to the seasonal dynamics of phytosanitary uses, such as chlortoluron and metolachlor. Atrazine, which was banned in 2003, and terbuthylazine, which was re-used in 2018, are interesting to compare because these triazines have similar properties but are not homologated at the same time. The metabolite / active ingredient ratios are used to show the dynamics of contamination in the river and in the groundwater, and to highlight groundwater-river exchanges. However, when studying these data, some inconsistencies appear, suggesting a new origin for atrazine and simazine. Key points ✓ The use of commercial terbuthylazine-based specialities brings atrazine and simazine residues into the catchment. ✓ The metabolite/active ingredient ratios make it possible to trace groundwater-river exchanges. ✓ Weed control practices in maize pose a high risk of river contamination

Nouvelles contaminations par les pesticides et leur utilisation comme traceur des masses d'eau

PIREN-Seine phase 8 -Rapport 2022The pesticide monitoring in the Orgeval catchment (France) was initiated in 2008 in order to understand the long-term fate of pesticides and to validate the transfer model developed within the framework of PIREN-Seine. Thus, 12 years of contamination data are now available for a list of molecules that is still evolving according to new uses. At the same time, past phytosanitary practices were determined in the basin. The assessments of current uses are extracted from the BNV-D for the Seine-et-Marne department. A focus is made on the emblematic substances for which the evolution trend can be directly related to the seasonal dynamics of phytosanitary uses, such as chlortoluron and metolachlor. Atrazine, which was banned in 2003, and terbuthylazine, which was re-used in 2018, are interesting to compare because these triazines have similar properties but are not homologated at the same time. The metabolite / active ingredient ratios are used to show the dynamics of contamination in the river and in the groundwater, and to highlight groundwater-river exchanges. However, when studying these data, some inconsistencies appear, suggesting a new origin for atrazine and simazine. Key points ✓ The use of commercial terbuthylazine-based specialities brings atrazine and simazine residues into the catchment. ✓ The metabolite/active ingredient ratios make it possible to trace groundwater-river exchanges. ✓ Weed control practices in maize pose a high risk of river contamination