title: Factors determining the attenuation of chlorinated aliphatic hydrocarbons in eutrohic river sediment impacted by discharging polluted groundwater.
abstract: This study explored the potential of eutrophic river sediment to attenuate the infiltration of chlorinated aliphatic hydrocarbon (CAH)-polluted groundwater discharging into the Zenne River near Brussels, Belgium. Active CAH biodegradation by reductive dechlorination in the sediment was suggested by a high dechlorination activity in microcosms containing sediment samples and the detection of dechlorination products in sediment pore water. A unique hydrogeochemical evaluation, including a delta2H and delta18O stable isotope approach, allowed to determine the contribution of different abiotic and biotic CAH attenuation processes and to delineate their spatial distribution inthe riverbed. Reductive dechlorination of the CAHs seemed to be the most widespread attenuation process, followed by dilution by unpolluted groundwater discharge and by surface water mixing. Although CAHs were never detected in the surface water, 26-28% of the investigated locations in the riverbed did not show CAH attenuation. We conclude that the riverbed sediments can attenuate infiltrating CAHs to a certain extent, but will probably not completely prevent CAHs to discharge from the contaminated groundwater into the Zenne River.
authors.affiliation: Flemish Institute for Technological Research (VITO), Separation and Conversion Technology, Boeretang 200, 2400 Mol, Belgium.
authors.forename: Kelly
authors.initials: K
authors.lastname: Hamonts
authors.forename: Thomas
authors.initials: T
authors.lastname: Kuhn
authors.forename: Miranda
authors.initials: M
authors.lastname: Maesen
authors.forename: Jan
authors.initials: J
authors.lastname: Bronders
authors.forename: Richard
authors.initials: R
authors.lastname: Lookman
authors.forename: Harald
authors.initials: H
authors.lastname: Kalka
authors.forename: Ludo
authors.initials: L
authors.lastname: Diels
authors.forename: Rainer U
authors.initials: RU
authors.lastname: Meckenstock
authors.forename: Dirk
authors.initials: D
authors.lastname: Springael
authors.forename: Winnie
authors.initials: W
authors.lastname: Dejonghe
mesh_terms: D001530:Belgium; D005068:Eutrophication; D019015:Geologic Sediments / Q000737:chemistry*; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D045483:Rivers / Q000737:chemistry*; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
chemical_list: D006843:Hydrocarbons, Chlorinated; D014874:Water Pollutants, Chemical