title: Coupled effects of hydrodynamics and biogeochemistry on Zn mobility and speciation in highly contaminated sediments.
abstract: Porewater transport and diagenetic reactions strongly regulate the mobility of metals in sediments. We executed a series of laboratory experiments in Gust chamber mesocosms to study the effects of hydrodynamics and biogeochemical transformations on the mobility and speciation of Zn in contaminated sediments from Lake DePue, IL. X-ray absorption spectroscopy (XAS) indicated that the oxidation of surficial sediments promoted the formation of more mobile Zn species. Bulk chemical measurements of porewater, overlying water, and sediment also suggested that this process liberated aqueous metals to porewater and facilitated Zn efflux to the overlying water. In addition, sediment resuspension events increased the release of aqueous metals to both surficial porewater and the overlying water column. XAS analysis indicated that resuspension increased dissolution of Zn-sequestering mineral phases. These results show that both steady slow porewater transport and rapid episodic resuspension are important to the release of metal from fine-grained, low-permeability contaminated sediments. Thus, information on metals speciation and mobility under time-varying overlying flow conditions is essential to understanding the long-term behavior of metals in contaminated sediments.
authors: †Department of Civil and Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3109, United States.|§Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031, China.
authors: Minwei
authors: M
authors: Xie
authors: †Department of Civil and Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3109, United States.
authors: Brooke A
authors: BA
authors: Jarrett
authors: †Department of Civil and Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3109, United States.
authors: Cécile
authors: C
authors: Da Silva-Cadoux
authors: ‡School of Natural Resources and Environment, University of Michigan, Ann Arbor, Michigan 48109, United States.
authors: Kyle J
authors: KJ
authors: Fetters
authors: ‡School of Natural Resources and Environment, University of Michigan, Ann Arbor, Michigan 48109, United States.
authors: G Allen
authors: GA
authors: Burton
authors: †Department of Civil and Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3109, United States.
authors: Jean-François
authors: JF
authors: Gaillard
authors: †Department of Civil and Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3109, United States.
authors: Aaron I
authors: AI
authors: Packman
mesh_terms: D000143:Acids / Q000737:chemistry; D019015:Geologic Sediments / Q000737:chemistry*; D057446:Hydrodynamics; D007087:Illinois; D016062:Porosity; D013052:Spectrometry, X-Ray Emission; D013440:Sulfides / Q000032:analysis; D014835:Volatilization; D014874:Water Pollutants, Chemical / Q000032:analysis*; D015032:Zinc / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D000143:Acids; D013440:Sulfides; D014874:Water Pollutants, Chemical; D015032:Zinc