title: Simulation of carrier-facilitated transport of phenanthrene in a layered soil profile.
abstract: The appropriate prediction of the fate of the contaminant is an essential step when evaluating the risk of severe groundwater pollutions-in particular in the context of natural attenuation. We numerically study the reactive transport of phenanthrene at the field scale in a multilayer soil profile based on experimental data. The effect of carrier facilitation by dissolved organic carbon is emphasized and incorporated in the model. Previously published simulations are restricted to the saturated zone and/or to homogeneous soil columns at the laboratory scale. A numerical flow and transport model is extended and applied to understand and quantify the relevant processes in the case of a strongly sorbing hydrophobic organic compound that is subject to carrier facilitation in the unsaturated zone. The contaminant migration is investigated on long- and short-term time scales and compared to predictions without carrier facilitation. The simulations demonstrate the importance of carrier facilitation and suggest strongly to take this aspect into account. By carrier facilitation breakthrough times at the groundwater level decreased from 500 to approximately 8 years and concentration peaks increased by two orders of magnitude in the long-term simulation assuming a temporary spill in an initially unpolluted soil with a non-sorbing carrier.
authors.affiliation: Institute for Applied Mathematics, University of Erlangen-Nuremberg, Germany. prechtel@am.uni-erlangen.de
authors.forename: Alexander
authors.initials: A
authors.lastname: Prechtel
authors.forename: Peter
authors.initials: P
authors.lastname: Knabner
authors.forename: Eckhard
authors.initials: E
authors.lastname: Schneid
authors.forename: Kai Uwe
authors.initials: KU
authors.lastname: Totsche
mesh_terms: D002244:Carbon / Q000737:chemistry; D003198:Computer Simulation; D008962:Models, Theoretical; D009930:Organic Chemicals / Q000737:chemistry; D010616:Phenanthrenes / Q000032:analysis*; D016062:Porosity; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D012995:Solubility; D013997:Time Factors; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D009930:Organic Chemicals; D010616:Phenanthrenes; D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; C031181:phenanthrene; D002244:Carbon