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Title: Geochemistry of a permeable reactive barrier for metals and acid mine drainage

Abstract

A permeable reactive barrier, designed to remove metals and generate alkalinity by promoting sulfate reduction and metal sulfide precipitation, was installed in August 1995 into an aquifer containing effluent from mine tailings. Passage of groundwater through the barrier results in striking improvement in water quality. Dramatic changes in concentrations of SO{sub 4}, Fe, trace metals, and alkalinity are observed. Populations of sulfate reducing bacteria are 10,000 times greater, and bacterial activity, as measured by dehydrogenase activity, is 10 times higher within the barrier compared to the up-gradient aquifer. Dissolved sulfide concentrations increase by 0.2--120 mg/L, and the isotope {sup 34}S is enriched relative to {sup 32}S in the dissolved phase SO{sub 4}{sup 2{minus}} within the barrier. Water chemistry, coupled with geochemical speciation modeling, indicates the pore water in the barrier becomes supersaturated with respect to amorphous Fe sulfide. Solid phase analysis of the reactive mixture indicates the accumulation of Fe monosulfide precipitates. Shifts in the saturated states of carbonate, sulfate, and sulfide minerals and most of the observed changes in water chemistry in the barrier and down-gradient aquifer can be attributed, either directly or indirectly, to bacterially mediated sulfate reduction.

Authors:
; ; ;  [1];  [2]
  1. Univ. of Waterloo, Ontario (Canada). Dept. of Earth Sciences
  2. CANMET, Ottawa, Ontario (Canada)
Publication Date:
OSTI Identifier:
687396
Resource Type:
Journal Article
Journal Name:
Environmental Science and Technology
Additional Journal Information:
Journal Volume: 33; Journal Issue: 16; Other Information: PBD: 15 Aug 1999
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; GEOCHEMISTRY; CONTAINMENT SYSTEMS; REMEDIAL ACTION; ACID MINE DRAINAGE; SULFATES; GROUND WATER; IRON; NICKEL; PH VALUE; WATER CHEMISTRY; BIODEGRADATION

Citation Formats

Benner, S.G., Blowes, D.W., Herbert, R.B. Jr., Ptacek, C.J., and Gould, W.D. Geochemistry of a permeable reactive barrier for metals and acid mine drainage. United States: N. p., 1999. Web. doi:10.1021/es981040u.
Benner, S.G., Blowes, D.W., Herbert, R.B. Jr., Ptacek, C.J., & Gould, W.D. Geochemistry of a permeable reactive barrier for metals and acid mine drainage. United States. doi:10.1021/es981040u.
Benner, S.G., Blowes, D.W., Herbert, R.B. Jr., Ptacek, C.J., and Gould, W.D. Sun . "Geochemistry of a permeable reactive barrier for metals and acid mine drainage". United States. doi:10.1021/es981040u.
@article{osti_687396,
title = {Geochemistry of a permeable reactive barrier for metals and acid mine drainage},
author = {Benner, S.G. and Blowes, D.W. and Herbert, R.B. Jr. and Ptacek, C.J. and Gould, W.D.},
abstractNote = {A permeable reactive barrier, designed to remove metals and generate alkalinity by promoting sulfate reduction and metal sulfide precipitation, was installed in August 1995 into an aquifer containing effluent from mine tailings. Passage of groundwater through the barrier results in striking improvement in water quality. Dramatic changes in concentrations of SO{sub 4}, Fe, trace metals, and alkalinity are observed. Populations of sulfate reducing bacteria are 10,000 times greater, and bacterial activity, as measured by dehydrogenase activity, is 10 times higher within the barrier compared to the up-gradient aquifer. Dissolved sulfide concentrations increase by 0.2--120 mg/L, and the isotope {sup 34}S is enriched relative to {sup 32}S in the dissolved phase SO{sub 4}{sup 2{minus}} within the barrier. Water chemistry, coupled with geochemical speciation modeling, indicates the pore water in the barrier becomes supersaturated with respect to amorphous Fe sulfide. Solid phase analysis of the reactive mixture indicates the accumulation of Fe monosulfide precipitates. Shifts in the saturated states of carbonate, sulfate, and sulfide minerals and most of the observed changes in water chemistry in the barrier and down-gradient aquifer can be attributed, either directly or indirectly, to bacterially mediated sulfate reduction.},
doi = {10.1021/es981040u},
journal = {Environmental Science and Technology},
number = 16,
volume = 33,
place = {United States},
year = {1999},
month = {8}
}