The Reactivity of Sulphur-Rich Sediments in Lake Junin, Peru: The Importance of Permanent Submergence

Martin, Alan J. ; McNee, J. Jay ; Pedersen, Thomas F.
Organization: Society for Mining, Metallurgy & Exploration
Pages: 8
Publication Date: Jan 1, 2000
Field sampling was conducted in Lake Junin, Peru in order to assess the post-depositional reactivity of the highly contaminated lake sediments. High resolution profiles of dissolved Fe, Mn, SO42- and H2S across the sediment-water interface illustrate that the organic-rich sediments in the main basin become anoxic within several millimetres of the sediment-water interface. These permanently submerged deposits in the main basin serve as a diffusive sink for dissolved Zn and Cu. Conversely, the periodically unsaturated deposits in shallow areas are characterized by the remobilization of Zn and Cu in the deep acidic (pH < 4) pore waters, resulting in the release of these metals to the overlying water column.
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