Direct observation of heavy metal-mineral association from the Clark Fork River Superfund Complex: Implications for metal transport and bioavailability

Two sets of samples from riverbeds and adjacent floodplains, separated by 80 river kilometers, were collected from the Clark Fork River Superfund Complex, Montana, (the largest Superfund site in the United States), and studied primarily with transmission electron microscopy (TEM) with several supporting techniques to determine heavy metal-mineral association. Seven of the eight samples studied were strongly influenced by material that once resided in mining and smelting dumps and impoundments; this material was transported downstream sometime during the last century and a half from the Butte/Anaconda areas. The eighth sample was from a deeper floodplain level and dates to premining days. The TEM observations afford a direct look, down to the nanometer level, at secondary mineral formation as a result of the breakdown of sulfides and silicates in the acid environment of this massive mine-drainage system. In the shallow, oxic floodplain sediments, heavy metals of concern in this system (As, Cu, Pb, and Zn) are taken up by the formation of sulfates (particularly Pb in jarosite), as well as hydrous metal oxides (As, Cu, Pb, and Zn in and on ferrihydrite, and a possibly new vernadite-like mineral). The oxides are long-lived in these systems, as they were also found in the anoxic riverbeds. Metals are also taken up by the formation of sulfides in sulfate-reducing environments as observed in the formation of nanoclusters of chalcopyrite and sphalerite. In all samples, clays make up between 5 and 20% of the sediment and carry significant amounts of Cu and Zn. The hydrous oxides, secondary sulfides, and clays provide several routes for metal transport downstream over long distances. Besides the potential bioavailability of heavy metals exchanged on and off the hydrous metal oxides and clays, nanometer-sized sulfides may also be highly reactive in the presence of biologic systems.

[1]  J. Leckie,et al.  MULTIPLE-SITE ADSORPTION OF CD, CU, ZN, AND PB ON AMORPHOUS IRON OXYHYDROXIDE , 1981 .

[2]  A. Manceau,et al.  Structure of heavy metal sorbed birnessite. Part III: Results from powder and polarized extended X-ray absorption fine structure spectroscopy , 2002 .

[3]  D. C. Marron.  Physical and chemical characteristics of a metal‐contaminated overbank deposit, west‐central South Dakota, U.S.A. , 1989 .

[4]  David B. Williams,et al.  Transmission Electron Microscopy: A Textbook for Materials Science , 1996 .

[5]  S. E. O'reilly,et al.  Lead Sorption Efficiencies of Natural and Synthetic Mn and Fe-oxides , 2002 .

[6]  A. Putnis,et al.  A TEM study of samples from acid mine drainage systems: metal-mineral association with implications for transport , 1999 .

[7]  Michael C. Newman,et al.  Metal Ecotoxicology Concepts and Applications , 1991 .

[8]  H. Galbraith,et al.  Effects of metals and arsenic on riparian communities in southwest Montana , 1996, Ecotoxicology.

[9]  J. Leckie,et al.  Competitive adsorption of cd, cu, zn, and pb on amorphous iron oxyhydroxide , 1981 .

[10]  Johnnie N. Moore,et al.  Hazardous wastes from large-scale metal extraction. A case study , 1990 .

[11]  J. L. Carter,et al.  Effects of Trace Metals on Aquatic Benthos , 1991 .

[12]  J. Banfield,et al.  Geochemical Modeling of ZnS in Biofilms: An Example of Ore Depositional Processes , 2002 .

[13]  F. Chung,et al.  Quantitative interpretation of X-ray diffraction patterns of mixtures. I. Matrix-flushing method for quantitative multicomponent analysis , 1974 .

[14]  S. Luoma,et al.  Large-scale distribution of metal contamination in the fine-grained sediments of the Clark Fork River, Montana, U.S.A. , 1991 .

[15]  Jerry R. Miller.  The role of fluvial geomorphic processes in the dispersal of heavy metals from mine sites , 1997 .

[16]  J. Jambor,et al.  Alunite-Jarosite Crystallography, Thermodynamics, and Geochronology , 2000 .

[17]  Roland Wiesendanger,et al.  Nanoscience and technology , 1998 .

[18]  D. Nordstrom,et al.  Iron and Aluminum Hydroxysulfates from Acid Sulfate Waters , 2000 .

[19]  David W. Blowes,et al.  Secondary minerals and acid mine-water chemistry , 1994 .

[20]  A. Putnis,et al.  Environmentally important, poorly crystalline Fe/Mn hydrous oxides: Ferrihydrite and a possibly new vernadite-like mineral from the Clark Fork River Superfund Complex , 2005 .

[21]  M. Hochella.  Nanoscience and technology: the next revolution in the Earth sciences , 2002 .

[22]  H. Wenk,et al.  Phyllosilicate alteration of plagioclase studied by transmission electron microscopy , 1979 .

[23]  Jan Środoń,et al.  Quantitative X-ray diffraction analysis of clay-bearing rocks from random preparations , 2001 .

[24]  Dennis D. Eberl,et al.  User Guide to RockJock - A Program for Determining Quantitative Mineralogy from X-Ray Diffraction Data , 2003 .

[25]  J. Banfield,et al.  Formation of sphalerite (ZnS) deposits in natural biofilms of sulfate-reducing bacteria. , 2000, Science.

[26]  Jack L. Johnson,et al.  Quantitative X-Ray Powder Diffraction Method Using the Full Diffraction Pattern , 1987, Powder Diffraction.

[27]  A. S. Madden,et al.  A test of geochemical reactivity as a function of mineral size: Manganese oxidation promoted by hematite nanoparticles , 2005 .

[28]  Tom J. Coulthard,et al.  The impact of tailings dam spills and clean-up operations on sediment and water quality in river systems: the Rı́os Agrio–Guadiamar, Aznalcóllar, Spain , 2003 .

[29]  J. Post,et al.  Manganese oxide minerals: crystal structures and economic and environmental significance. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[30]  K. Pedersen,et al.  The environmental impact of mine wastes — Roles of microorganisms and their significance in treatment of mine wastes , 1996 .

[31]  K. Bencala,et al.  Coupling of hydrologic transport and chemical reactions in a stream affected by Acid mine drainage. , 1994, Environmental science & technology.