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Communication Dans Un Congrès Année : 2020

Reconstruction of long-term water quality trends using sediment databases: insights from a multi-criteria analysis performed on the four main French River Basins (1945 - 2018)

André-Marie Dendievel
Olivier Evrard
Alexandra Coynel
  • Fonction : Auteur
  • PersonId : 1106783
Pierre Labadie
Maxime Debret
Quentin Faivre
Thomas Gardes
Sophia Vauclin
  • Fonction : Auteur
  • PersonId : 1091487
Hélène Budzinski
Cécile Grosbois
Marc Desmet
T. Winiarski
  • Fonction : Auteur

Résumé

In the current context of increasing anthropogenic pressures on river systems, sediments can provide insightful archives to reconstruct the widespread contaminations that are reported on most large rivers across the world. Identification of the spatio-temporal trends of water quality remains challenging despite the increasing concerns that they have raised in the last several decades. Indeed, multi-criteria data syntheses are scarce at the river basin scale and source-to-estuary approaches are still needed to estimate contaminant loads delivered by rivers to the seas and to monitor the effects of public policies on contamination trends. Here, we present an approach built within the framework of the INTERPOL research program, the objective of which is to assess and compare pollution trends along major rivers of France on a multi-decadal time scale. The current research focused on the example provided by the polychlorinated biphenyls (PCBs) contamination trends that were reconstructed over the last 80 years (1945–2018) along the four main fluvial valleys in France (Rhône, Seine, Loire and Garonne Rivers). PCB analyses results (∑PCBi) conducted in the framework of both research and continuous monitoring programs and measured on different solid matrices (sediment cores, bed and flood deposits, suspended particulate matters, and dredged sediments) were compiled in this study. The relationships with socio-environmental factors were also deciphered by integrating hydrological and human spatio-temporal data (river discharge, population, urban and industrial areas). The quality of the data available varied according to the studied river: the Seine and Rhône Rivers were well documented, whereas a lower proportion of validated PCBs data (> limits of quantification) was available on the Garonne and Loire Rivers. Urban and industrial areas and accidental releases provided the main contributions to the PCB contamination of rivers downstream of Paris and Rouen (Seine River), around Lyon and its industrial corridor (Rhône River), in the Saint-Etienne and Nantes conurbations (Loire River), and probably downstream of Toulouse and Bordeaux (Garonne River). Two major temporal trends were found: (1) highly concentrated ∑PCBi releases (up to 4 mg.kg-1) until 1975, followed by a sharp decrease in ∑PCBi over the period 1975‑today (due to the implementation of environmental regulations) occurred on the Seine and the Loire Rivers. (2) ∑PCBi concentrations on the Rhône and Garonne Rivers are important until the 1990s, then decrease linearly until the 2010s and are stable since then. Calculated ∑PCBi loads since 1977 showed that the Rhône River provides the largest quantity of PCBs to the Mediterranean Sea, followed by the Seine and the Loire Rivers to the Atlantic Ocean and the English Channel, respectively. In contrast, low exports from the Garonne River to the Atlantic Ocean were reported. Through the global evaluation of PCBs fluxes delivered by rivers to the seas, we demonstrate the important role played by French rivers in the PCB contamination of European seas.
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Dates et versions

hal-03837336 , version 1 (02-11-2022)

Identifiants

  • HAL Id : hal-03837336 , version 1

Citer

André-Marie Dendievel, Brice Mourier, Olivier Evrard, Alexandra Coynel, Pierre Labadie, et al.. Reconstruction of long-term water quality trends using sediment databases: insights from a multi-criteria analysis performed on the four main French River Basins (1945 - 2018). 2nd International Conference on Contaminated Sediments, Jun 2020, Bern, Switzerland. ⟨hal-03837336⟩
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