Évaluation de la contamination des grands bassins fluviaux du monde à partir des flux spécifiques particulaires de micropolluants hérités

International audienc

Une lecture du statut économique des grands bassins fluviaux par l'évaluation de leur niveau de contamination aux micropolluants hérités

International audienc

Legacy‐micropollutant contamination levels in major river basins based on findings from the Rhône Sediment Observatory

International audienceFor more than half a century, chemical contamination has progressively spread to all the large river basins. Large river outlets integrate multiple anthropogenic pressures in watersheds, making them the largest source of sediment-bound contaminants to conti- nental shelf areas. However, comparing particulate micropollutant contaminations between the large river basins is a challenging task, especially due to the scarcity of long-term river monitoring programs. Here we address this issue, with a focus on leg- acy particulate micropollutants (polychlorobiphenyls [PCBi], polycyclic aromatic hydro- carbons [PAHs] and trace metal elements [TME]) yields. For this purpose, we employed a bottom-up multiscale approach to chemical contamination in river basins that takes micropollutant yields measured in the Rhône River sub-basins (France) as a benchmark of other large river basins. Data on the Rhône River basin came from a unique 10-year-long monitoring program within the Rhône Sediment Observatory (OSR), and were compared to data gathered on 18 major worldwide river outlets. The Rhône River basin is far cleaner now than a few decades ago, likely due to environmen- tal regulations. At a wider spatial scale, our results depict an overall contamination gra- dient splitting the most heavily contaminated river basins, located in developing and industrializing low-to-middle-income countries, from the least contaminated rivers located in developed high-income countries. We argue that chemical contamination levels of large river basins depend on their stage of economic development

Recommendations from a French-Swiss expert panel for improving the ecotoxicological quality assessment of sediments through the study of benthic communities

International audienceLes sédiments ont un rôle écologique essentiel pour de nombreuses espèces aquatiques.Toutefois, leur capacité à capter les polluants persistants peut participer à long termeà la contamination des milieux aquatiques. Aussi, afin de mieux prendre en compte les impactsécotoxicologiques de la contamination des sédiments et appréhender le risque écologiquequi en découle, il est important de disposer de méthodes d'évaluation robustes. Cet article présentela contribution d'un groupe franco-suisse réunissant chercheurs, gestionnaires et représentantsde bureaux d’études qui ont travaillé ensemble afin de dresser un état des lieux et formulerdes recommandations pour mieux caractériser la contamination des sédiments, les niveauxd’exposition des communautés benthiques et les effets possibles sur ces espèce