title: Spatial distribution of heavy metals in the surface soil of source-control stormwater infiltration devices - Inter-site comparison.
abstract: Stormwater runoff infiltration brings about some concerns regarding its potential impact on both soil and groundwater quality; besides, the fate of contaminants in source-control devices somewhat suffers from a lack of documentation. The present study was dedicated to assessing the spatial distribution of three heavy metals (copper, lead, zinc) in the surface soil of ten small-scale infiltration facilities, along with several physical parameters (soil moisture, volatile matter, variable thickness of the upper horizon). High-resolution samplings and in-situ measurements were undertaken, followed by X-ray fluorescence analyses and spatial interpolation. Highest metal accumulation was found in a relatively narrow area near the water inflow zone, from which concentrations markedly decreased with increasing distance. Maximum enrichment ratios amounted to >20 in the most contaminated sites. Heavy metal patterns give a time-integrated vision of the non-uniform infiltration fluxes, sedimentation processes and surface flow pathways within the devices. This element indicates that the lateral extent of contamination is mainly controlled by hydraulics. The evidenced spatial structure of soil concentrations restricts the area where remediation measures would be necessary in these systems, and suggests possible optimization of their hydraulic functioning towards an easier maintenance. Heterogeneous upper boundary conditions should be taken into account when studying the fate of micropollutants in infiltration facilities with either mathematical modeling or soil coring field surveys.
authors.affiliation: LEESU, UMR MA 102, École des Ponts, AgroParisTech, UPEC, UPE, Champs-sur-Marne, 6-8 avenue Blaise Pascal, Cité Descartes, 77455 Marne-la-Vallée Cedex 2, France; SEPIA, 53 rue de Turbigo, 75003 Paris, France. Electronic address: damien.tedoldi@enpc.fr.
authors.forename: Damien
authors.initials: D
authors.lastname: Tedoldi
authors.affiliation: LEESU, UMR MA 102, École des Ponts, AgroParisTech, UPEC, UPE, Champs-sur-Marne, 6-8 avenue Blaise Pascal, Cité Descartes, 77455 Marne-la-Vallée Cedex 2, France; Faculty of Engineering III, Lebanese University, Hadath, Lebanon. Electronic address: chebbo@enpc.fr.
authors.forename: Ghassan
authors.initials: G
authors.lastname: Chebbo
authors.affiliation: SEPIA, 53 rue de Turbigo, 75003 Paris, France. Electronic address: dp@sepia-uw.fr.
authors.forename: Daniel
authors.initials: D
authors.lastname: Pierlot
authors.affiliation: CEREMA, 12 Rue Léon Teisserenc de Bort, 78190 Trappes, France. Electronic address: philippe.branchu@cerema.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Branchu
authors.affiliation: SEPIA, 53 rue de Turbigo, 75003 Paris, France. Electronic address: yk@sepia-uw.fr.
authors.forename: Yves
authors.initials: Y
authors.lastname: Kovacs
authors.affiliation: LEESU, UMR MA 102, École des Ponts, AgroParisTech, UPEC, UPE, Champs-sur-Marne, 6-8 avenue Blaise Pascal, Cité Descartes, 77455 Marne-la-Vallée Cedex 2, France. Electronic address: gromaire@enpc.fr.
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Gromaire
keywords: Contamination; Metals; Runoff infiltration; Soil; Spatial distribution; Sustainable urban drainage systems