Speaker
Description
Urban stormwater management has become a major issue for local authorities facing the risk of flooding and pollution of receiving environments. Indeed, expansive urbanization leads to surface sealing and, consequently, water flows concentration and contaminants loads deposited on impervious surfaces. Rainwater management drainage systems play a dual role in reducing the volume of water discharged into receiving environments during rainfall events and purifying the water by settling contaminated particles while the water remains in the system (Monachese et al., 2025). The sediment deposit is a complex organo-mineral material where a significant proportion of the pollutants carried by runoff water accumulate. However, while the characterization of sediment as a pollutant stock is well documented – at least with regard to metal pollution – the issue of pollutant transfer to underlying porous media has received little attention (Tedoldi et al., 2016), even though there is growing encouragement for rainwater infiltration, particularly in the context of the development of the ‘sponge city’ concept (Nguyen et al., 2020). Among SUDS, infiltration basins in urban areas collect and infiltrate large volumes of water contaminated with dissolved and particulate metal and organic pollutants. In addition, since recent years it is possible to study the abundance of tyre and road wear particles (TRWPs) in environmental matrices, with the development of Pyr-GC-MS analysis techniques (ISO, 2017).
In this context, the presentation will review the knowledge gathered on the transfer of pollutants within an infiltration basin in the Nantes region that collects water from Chevire bridge carrying 100,000 vehicles per day (ONEVU-SNO Observil). The sediment, accumulating the pollution from runoff water, has been characterized in detail for trace metals, PAHs and recently for TRWPs (El Mufleh et al., 2014). Concentrations of copper and TRWP of around 180 mg/kg and up to 65 mg/g of sediment, respectively, have been recorded (Dang et al., 2022; de Oliveira et al., 2024). Trace metal mobility capacity from the sediment was evaluated by chemical extractions, showing the role of metallic oxides and organic matter as carrier phases (Clozel et al., 2006). Additional leaching experiments involving sediment in laboratory columns have highlighted the coupled transfer of copper with dissolved organic carbon from the solid matrix, along with various other trace metals and major elements, claiming for colloidal-assisted transfer of metals from the sediment to the underlying alluvial material (Durin et al., 2005). Finally, to assess in the field the pollutant transfer in porous material under the sediment, a grid of mini-piezometers was installed in the basin to collect and analyse pore water, revealing a mobile fraction of dissolved and colloidal copper with concentrations reaching 50 µg/L (Dang, 2023), confirming earlier preliminary results (Durin et al., 2007).
The current focus is on understanding the mechanisms of metal pollutant mobilization by modelling sediment reactivity (Banc et al., 2023; Doyon et al., 2026 (submitted)), the first step before representing pollutant transfer in this two-layer system (sediment and alluvial material) for configurations with variable water saturation in vadose zone.
Acknowledgements : funding from CNRS (OSUNA, IRSTV) and Pays-de-La-Loire Region
| References | Banc C., Gautier M., Blanc D., Lupsea-Toader M., Marsac R., Gourdon R., 2023. pH control on organic and organo-mineral colloids carrying major and trace elements in leachates of wetland sludge deposits, Chemical Engineering Journal, Volume 471, 2023, 144244, ISSN 1385-8947, https://doi.org/10.1016/j.cej.2023.144244.// Clozel B., Ruban V., Durand C., Conil P., 2006. Origin and mobility of heavy metals in contaminated sediments from retention and infiltration ponds. Appl. Geochem. 21, 1781–1798. // Dang D. P. T., Béchet B., Jean-Soro L. , 2022. Evaluation of ageing effect on trace element mobility in sediment of sustainable drainage systems by chemical extractions. EGU 23 - 27 May, Vienna, Austria // Dang D.P.T., 2023. Dynamique des contaminants métalliques en gestion des eaux pluviales : apports de la spéciation physique et chimique. Ph’D thesis, Nantes Univ. // De Oliveira T., Dang DPT, Chaillou M., Roy S., Caubrière N., Guillon M., Mabilais D., Ricordel S., Jean-Soro L., Béchet B., Muresan Paslaru B., Poirier L., Gasperi J., 2024. Tire and road wear particles in infiltration pond sediments: Occurrence, spatial distribution, size fractionation and correlation with metals. Science of The Total Environment, Volume 955, 176855, ISSN 0048-9697, https://doi.org/10.1016/j.scitotenv.2024.176855. // Doyon C., Blanc D., Gautier M., Béchet B., Geochemical modeling of metallic trace elements release from stormwater infiltration basin sediments, Novatech conference, Lyon, 2026 (submitted) // Durin B., Bechet B., Legret M., Le Cloirec P., 2007. Role of colloids in heavy metal transfer through a retention-infiltration basin. Water Science and Technology, 56(11) :91–99. // Durin B., Bechet B., Legret M., Le Cloirec P., 2005. Colloid-mediated release of heavy metals from a retention-infiltration pond sediment, Proceedings of the 8th international conference on the biogrochemistry of trace elements (ICOBTE), 3-7 april, Adelaide, Australia. // El-Mufleh A., Béchet B., Ruban V., Legret M., Clozel B., Barraud S., Gonzalez-Merchan C., Bedell J.-P., Delolme C., 2014. Review on physical and chemical characterizations of contaminated sediments from urban stormwater infiltration basins within the framework of the French observatory for urban hydrology (SOERE URBIS). Environ. Sci. Pollut. Res. 21, 5329–5346 //. ISO/TS 21396, 2017. Rubber — Determination of Mass Concentration of Tire and Road Wear Particles (TRWP) in Soil and Sediments — Pyrolysis-GC/MS Method, Switzerland // Monachese A.P., Gómez-Villarino M.T., López-Santiago J., Sanz E, Almeida-Ñauñay,A.F., Zubelzu S., 2025. Challenges and innovations in Urban Drainage Systems: Sustainable Drainage Systems Focus. Water ,17, 76. https://doi.org/10.3390/w17010076 // Nguyen T.T., Ngo H.H., Guo W., Wang C.W., 2020. A new model framework for sponge city implementation: Emerging challenges and future developments, Journal of Environmental Management, https://doi.org/10.1016/j.jenvman.2019.109689 // Tedoldi D., Chebbo G., Pierlot D., Kovacs Y., Gromaire M.-C., 2016. Impact of runoff infiltration on contaminant accumulation and transport in the soil/filter media of Sustainable Urban Drainage Systems: A literature review. Sci. Total Environ. 569–570, 904–926. |
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| Country | FRANCE |
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