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Metal cycling during sediment early diagenesis in a water reservoir affected by acid mine drainage.
Sci Total Environ. 2013 Sep 01; 461-462:416-29.ST

Abstract

The discharge of acid mine drainage (AMD) into a reservoir may seriously affect the water quality. To investigate the metal transfer between the water and the sediment, three cores were collected from the Sancho Reservoir (Iberian Pyrite Belt, SW Spain) during different seasons: turnover event; oxic, stratified period; anoxic and under shallow perennially oxic conditions. The cores were sliced in an oxygen-free atmosphere, after which pore water was extracted by centrifugation and analyzed. A sequential extraction was then applied to the sediments to extract the water-soluble, monosulfide, low crystallinity Fe(III)-oxyhydroxide, crystalline Fe(III)-oxide, organic, pyrite and residual phases. The results showed that, despite the acidic chemistry of the water column (pH<4), the reservoir accumulated a high amount of autochthonous organic matter (up to 12 wt.%). Oxygen was consumed in 1mm of sediment due to organic matter and sulfide oxidation. Below the oxic layer, Fe(III) and sulfate reduction peaks developed concomitantly and the resulting Fe(II) and S(II) were removed as sulfides and probably as S linked to organic matter. During the oxic season, schwertmannite precipitated in the water column and was redissolved in the organic-rich sediment, after which iron and arsenic diffused upwards again to the water column. The flux of precipitates was found to be two orders of magnitude higher than the aqueous one, and therefore the sediment acted as a sink for As and Fe. Trace metals (Cu, Zn, Cd, Pb, Ni, Co) and Al always diffused from the reservoir water and were incorporated into the sediments as sulfides and oxyhydroxides, respectively. In spite of the fact that the benthic fluxes estimated for trace metal and Al were much higher than those reported for lake and marine sediments, they only accounted for less than 10% of their total inventory dissolved in the column water.

Authors+Show Affiliations

Institute of Environment Assessment and Water Research (IDAEA), CSIC, C/Jordi Girona 18-26, 08034 Barcelona, Spain. ester.torres@idaea.csic.esNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

23747557

Citation

Torres, E, et al. "Metal Cycling During Sediment Early Diagenesis in a Water Reservoir Affected By Acid Mine Drainage." The Science of the Total Environment, vol. 461-462, 2013, pp. 416-29.
Torres E, Ayora C, Canovas CR, et al. Metal cycling during sediment early diagenesis in a water reservoir affected by acid mine drainage. Sci Total Environ. 2013;461-462:416-29.
Torres, E., Ayora, C., Canovas, C. R., García-Robledo, E., Galván, L., & Sarmiento, A. M. (2013). Metal cycling during sediment early diagenesis in a water reservoir affected by acid mine drainage. The Science of the Total Environment, 461-462, 416-29. https://doi.org/10.1016/j.scitotenv.2013.05.014
Torres E, et al. Metal Cycling During Sediment Early Diagenesis in a Water Reservoir Affected By Acid Mine Drainage. Sci Total Environ. 2013 Sep 1;461-462:416-29. PubMed PMID: 23747557.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Metal cycling during sediment early diagenesis in a water reservoir affected by acid mine drainage. AU - Torres,E, AU - Ayora,C, AU - Canovas,C R, AU - García-Robledo,E, AU - Galván,L, AU - Sarmiento,A M, Y1 - 2013/06/05/ PY - 2013/02/28/received PY - 2013/05/06/revised PY - 2013/05/06/accepted PY - 2013/6/11/entrez PY - 2013/6/12/pubmed PY - 2014/3/7/medline KW - Benthic fluxes KW - Diffusion KW - Iron reduction KW - Organic matter KW - Sequential extraction KW - Sulfate reduction SP - 416 EP - 29 JF - The Science of the total environment JO - Sci Total Environ VL - 461-462 N2 - The discharge of acid mine drainage (AMD) into a reservoir may seriously affect the water quality. To investigate the metal transfer between the water and the sediment, three cores were collected from the Sancho Reservoir (Iberian Pyrite Belt, SW Spain) during different seasons: turnover event; oxic, stratified period; anoxic and under shallow perennially oxic conditions. The cores were sliced in an oxygen-free atmosphere, after which pore water was extracted by centrifugation and analyzed. A sequential extraction was then applied to the sediments to extract the water-soluble, monosulfide, low crystallinity Fe(III)-oxyhydroxide, crystalline Fe(III)-oxide, organic, pyrite and residual phases. The results showed that, despite the acidic chemistry of the water column (pH<4), the reservoir accumulated a high amount of autochthonous organic matter (up to 12 wt.%). Oxygen was consumed in 1mm of sediment due to organic matter and sulfide oxidation. Below the oxic layer, Fe(III) and sulfate reduction peaks developed concomitantly and the resulting Fe(II) and S(II) were removed as sulfides and probably as S linked to organic matter. During the oxic season, schwertmannite precipitated in the water column and was redissolved in the organic-rich sediment, after which iron and arsenic diffused upwards again to the water column. The flux of precipitates was found to be two orders of magnitude higher than the aqueous one, and therefore the sediment acted as a sink for As and Fe. Trace metals (Cu, Zn, Cd, Pb, Ni, Co) and Al always diffused from the reservoir water and were incorporated into the sediments as sulfides and oxyhydroxides, respectively. In spite of the fact that the benthic fluxes estimated for trace metal and Al were much higher than those reported for lake and marine sediments, they only accounted for less than 10% of their total inventory dissolved in the column water. SN - 1879-1026 UR - https://www.unboundmedicine.com/medline/citation/23747557/Metal_cycling_during_sediment_early_diagenesis_in_a_water_reservoir_affected_by_acid_mine_drainage_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0048-9697(13)00557-3 DB - PRIME DP - Unbound Medicine ER -