title: Copper and nickel partitioning with nanoscale goethite under variable aquatic conditions.
abstract: Metal contaminated sediments can be toxic to aquatic organisms and are common in human-dominated ecosystems, which results in metals being a leading cause of ecosystem impairment. Bioavailability of metals is influenced by their affinity for dissolved and solid-phase ligands, including iron (Fe) oxyhydroxides, which have been hypothesized to reduce metal toxicity in sediments. The authors examined the adsorption kinetics of copper (Cu) and nickel (Ni) with goethite (α-FeOOH) and characterized the influences of solute metal concentration, pH, ionic strength, and humate concentration on steady-state partitioning of the metals with goethite under conditions representative of natural aquatic environments. Copper and Ni readily adsorbed to goethite, and steady-state partitioning was achieved within 2 h. Although ionic strength had no effect on metal partitioning, adsorption of Cu and Ni to goethite was enhanced by alkaline pH and reduced by competition with humate. Because distribution coefficient (KD ) values for Cu and Ni from the present study are comparable to values measured in natural systems, the authors hypothesize that goethite may contribute significantly to the adsorption of both Ni and Cu to particles in the environment. The authors suggest that incorporating binding by Fe oxides in metal bioavailability models should be a priority for improving risk assessment of metal-contaminated oxic sediments.
authors.affiliation: Department of Earth and Environmental Sciences, Wright State University, Dayton, Ohio, USA.
authors.forename: Kelsey M
authors.initials: KM
authors.lastname: Danner
authors.affiliation: Department of Earth and Environmental Sciences, Wright State University, Dayton, Ohio, USA.
authors.forename: Chad R
authors.initials: CR
authors.lastname: Hammerschmidt
authors.affiliation: Department of Biological Sciences, Kent State University, Kent, Ohio, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Costello
authors.affiliation: School of Natural Resources and Environment, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: G Allen
authors.initials: GA
authors.lastname: Burton
mesh_terms: D000327:Adsorption; D003300:Copper / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry; D006812:Humic Substances / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D058085:Iron Compounds / Q000737:chemistry*; D007700:Kinetics; D008903:Minerals / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry*; D009994:Osmolar Concentration; D012996:Solutions / Q000737:chemistry
chemical_list: D006812:Humic Substances; D058085:Iron Compounds; D008903:Minerals; D012996:Solutions; C094886:goethite; D003300:Copper; D009532:Nickel
keywords: Adsorption; Metal bioavailability; Sediment chemistry