Metal(loid) Diagenesis in Mine-Impacted Sediments of Lake Coeur d'Alene, Idaho

Abstract

Mining activity along the South Fork of the Coeur d' Alene River in northern Idaho has resulted in fluvial mine tailings enriched in Pb, As, Ag, Sb, Hg, Cd, and Zn deposited on the lakebed of Lake Coeur d'Alene, thus serving as a potential benthic source of inorganic contaminants. Our objective was to characterize the dominant solid phase materials and diagenetic processes controlling metal(loid) solubilities, and thus their potential release to the overlying water column. Aqueous and solid concentrations of metal(loid) contaminants were examined along with distinct species of Fe and S within sediments and interstitial water. A gradient from oxic conditions at the sediment-water interface to anoxic conditions below 15 cm exists at all sites, resulting in a dynamic redox environment that controls the partitioning of contaminants. Fluvial deposition from frequent seasonal flood events bury ferric oxides residing at the sediment-water interface leading to reductive dissolution as they transition to the anoxic zone, consequently releasing associated metal(loids) to the interstitial water. Insufficient sulfur limits the formation of sulfidic minerals, but high carbonate content of this mining region buffers pH and promotes formation of siderite. Diagenetic reactions create chemical gradients encouraging the diffusion of metal(loids) toward the sediment--water interface, thereby, increasing the potential for release into the overlying water.

The impacts of different long-term fertilization regimes on the bioavailability of arsenic in soil: integrating chemical approach with Escherichia coli arsRp::luc-based biosensor

“…Recently, BCR-SEPs were widely used to analyze different metal fractions which could reflect the release of metal from solid-phase soil and metal mobility in soil (Degryse et al 2009;Giller et al 2009;Peijnenburg et al 2007). Although sequential extraction procedures have been popularized in the analysis of metal fractions, it was still criticized because of its low repeatability and representativeness due to the use of different reagents and procedures (Filgueiras et al 2002;Nolan et al 2003;Toevs et al 2006).…”

Heavy Metal–Mineral Associations in Coeur d’Alene River Sediments: A Synchrotron-Based Analysis

“…Inclusion of pyrite (3 mol%) in the LC k 3 -weighted EXAFS spectral fitting improved the χ 2 value for the fit by 22% and was thus included in the fit despite its low concentration. The presence of pyrite has been observed in earlier studies (Toevs et al 2006). To clearly distinguish ferrihydrite from goethite by LC-EXAFS fitting, one needs EXAFS data up to 14 k (Å −1 ).…”

“…Rapid oxidation of sediment and pore water Fe(II) to Fe(III) hydroxides has been observed by others in this system upon exposure to oxygen after sampling (Horowitz et al 1995b). The anoxic boundary in LCdA has been reported at the water-sediment interface (Harrington et al 1998b), within 5 cm into the sediments (La Force et al 1999;Toevs et al 2006) and between 10 and 15 cm in the sediments (Horowitz et al 1992) and this variability may exist in CdAR as well. As this study focused on sediment cores extracted from the top 15 cm, the majority of the core may have been oxic and thus contained little dissolved Fe.…”

“…Fe minerals including siderite, magnetite, pyrite, pyrrhotite, goethite, hematite, and ferrihydrite have been reported in sediments of LCdA and in the upstream mining district (Farrand and Harsanyi 1997;Cummings et al 2000;Toevs et al 2006).…”

“…Analyses of the sediment and water in the Coeur d'Alene system have been examined by others focusing on geology and geochemistry (Grieco 1981;Farrand and Harsanyi 1997;Rosenberg and Larson 2000;Fleck et al 2002;Mauk and White 2004), as well as surface and subsurface sediment contamination and benthic transport (Maxfield et al 1974a; Reece et al 1978;Horowitz et al 1992Horowitz et al , 1995aHorowitz 1993;Woods and Beckwith 1997;Harrington et al 1998a, b;La Force et al 1998, 1999Winowiecki 2002;Kuwabara et al 2003;Toevs et al 2006). Contamination of lateral lakes adjacent to the delta (Harrington et al 1998a;Sprenke et al 2000;Bostick et al 2001), CdAR and upstream tributary contamination (Maxfield et al 1974b;Reece et al 1978;Paulson 1997;Farag et al 1998Farag et al , 2000La Force et al 1998;Balistrieri et al 2003;Box et al 2005), and downstream of LCdA (Grosbois et al 2001) have also been studied.…”