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This article in JEQ

  1. Vol. 40 No. 2, p. 484-491
     
    Received: Apr 3, 2009
    Published: Mar, 2011


    * Corresponding author(s): atk@rice.edu
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doi:10.2134/jeq2009.0124

Mobilization of Trace Metals and Inorganic Compounds during Resuspension of Anoxic Sediments from Trepangier Bayou, Louisiana

  1. Heather J. Shipleya,
  2. Yan Gaob,
  3. Amy T. Kan *b and
  4. Mason B. Tomsonb
  1. a Dep. of Civil and Environmental Engineering, Univ. of Texas at San Antonio, One UTSA Cir., San Antonio, TX 78249
    b Dep. Of Civil and Environmental Engineering, Rice Univ., 6100 S. Main St., MS-519, Houston, TX 77005-1892. Assigned to Associate Editor Hao Zhang

Abstract

The release of trace metals (Mn, Ni, Co, Cu, Zn, Pb, and Cd) and inorganic compounds (As) from initially anoxic Trepangier Bayou sediments, Louisiana and the sources of the released metals were investigated. After 1 to 2 d aeration, significant amounts of trace metals (Mn, Zn, Cd, Ni, and Co) were released to the aqueous phase with increased acidity, primarily due to the oxidation of acid-volatile sulfide and ferrous iron and iron sulfide minerals. The addition of a bacterial inhibitor, NaN3, to the Trepangier sediment during resuspension inhibited metal release, suggesting that microbial catalysis can regulate metal mobilization during sediment resuspension. In a well buffered system, oxidation of iron sulfides alone did not appear to induce trace metal release. Moreover, when Trepangier sediment was resuspended in anoxic conditions at neutral pH, <1% of the trace metal content was released, whereas a significant release of metal was observed under acidic anoxic conditions. Although oxidation of iron sulfide minerals is an essential prerequisite for the release of Zn, Co, Cd, and Ni, carbonates and oxides also play a role. The trace metals and inorganic compounds investigated could be classified into three groups according to their release characteristics: (i) Mn, Zn, Cd, Ni, and Co; (ii) Fe, Pb, and As; and (iii) Cu. The groupings appeared to depend on the sources of compounds and their relative affinity, after oxidation, to iron oxyhydroxides or organic matter.

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Copyright © 2011. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyAmerican Society of Agronomy, Crop Science Society of America, and Soil Science Society of America