title: Dynamics of dissolved organic carbon (DOC) through stormwater basins designed for groundwater recharge in urban area: Assessment of retention efficiency.
abstract: Managed aquifer recharge (MAR) has been developed in many countries to limit the risk of urban flooding and compensate for reduced groundwater recharge in urban areas. The environmental performances of MAR systems like infiltration basins depend on the efficiency of soil and vadose zone to retain stormwater-derived contaminants. However, these performances need to be finely evaluated for stormwater-derived dissolved organic matter (DOM) that can affect groundwater quality. Therefore, this study examined the performance of MAR systems to process DOM during its transfer from infiltration basins to an urban aquifer. DOM characteristics (fluorescent spectroscopic properties, biodegradable and refractory fractions of dissolved organic carbon -DOC-, consumption by micro-organisms during incubation in slow filtration sediment columns) were measured in stormwater during its transfer through three infiltration basins during a stormwater event. DOC concentrations sharply decreased from surface to the aquifer for the three MAR sites. This pattern was largely due to the retention of biodegradable DOC which was more than 75% for the three MAR sites, whereas the retention of refractory DOC was more variable and globally less important (from 18% to 61% depending on MAR site). Slow filtration column experiments also showed that DOC retention during stormwater infiltration through soil and vadose zone was mainly due to aerobic microbial consumption of the biodegradable fraction of DOC. In parallel, measurements of DOM characteristics from groundwaters influenced or not by MAR demonstrated that stormwater infiltration increased DOC quantity without affecting its quality (% of biodegradable DOC and relative aromatic carbon content -estimated by SUVA254-). The present study demonstrated that processes occurring in soil and vadose zone of MAR sites were enough efficient to limit DOC fluxes to the aquifer. Nevertheless, the enrichments of DOC concentrations measured in groundwater below infiltration basins need to be considered in future studies to especially assess their impact on groundwater quality.
authors.affiliation: Université de Lyon, UMR 5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, CNRS, ENTPE, 6 Rue Raphaël Dubois, 69622 Villeurbanne, France. Electronic address: mermillo@univ-lyon1.fr.
authors.forename: Florian
authors.initials: F
authors.lastname: Mermillod-Blondin
authors.affiliation: Université de Lyon, UMR 5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, CNRS, ENTPE, 6 Rue Raphaël Dubois, 69622 Villeurbanne, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Simon
authors.affiliation: Université de Lyon, UMR 5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, CNRS, ENTPE, 6 Rue Raphaël Dubois, 69622 Villeurbanne, France.
authors.forename: Chafik
authors.initials: C
authors.lastname: Maazouzi
authors.affiliation: Irstea, Groupement de Lyon, UR MALY, 5 rue de la Doua, 69626 Villeurbanne, France; Laboratoire d'Ecologie Alpine, UMR 5553, Université Grenoble Alpes, BP 53, 38041 Grenoble, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Foulquier
authors.affiliation: Université de Lyon, UMR 5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, CNRS, ENTPE, 6 Rue Raphaël Dubois, 69622 Villeurbanne, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Delolme
authors.affiliation: Université de Lyon, UMR 5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, CNRS, ENTPE, 6 Rue Raphaël Dubois, 69622 Villeurbanne, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Marmonier
mesh_terms: D002244:Carbon / Q000032:analysis*; D004323:Drainage, Sanitary / Q000379:methods*; D005374:Filtration; D060587:Groundwater / Q000737:chemistry* / Q000382:microbiology; D011891:Rain; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D012987:Soil; D014874:Water Pollutants, Chemical; D002244:Carbon
keywords: Biodegradability; Fluorescent properties; Microbial respiration; PARAFAC; SUVA; Slow filtration columns; Urban stormwater quality