Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

Abstract

Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Waterchemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H 2 S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34 S/ 32 S and 18 O/ 16 O in dissolved SO 4 that are 2-3 ‰ heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron-and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures.

Geochemistry of acid mine drainage from a coal mining area and processes controlling metal attenuation in stream waters, southern Brazil

“…However, studies on the environmental impact by coal mining are relatively recent in Brazil (Teixeira et al 2000, Pampêo et al 2004. Special attention has been given to acid drainage remediation (Fungaro and Izidoro 2006, Soares et al 2006, Church et al 2007), but few studies have focused on the regional characterization of water systems and AMD influence on their physico-chemical conditions. The main objective of this study was to evaluate the possible influence of the acid drainage coming from a mining area within the Figueira region on the quality of surface and ground waters particularly in relation to metals and As.…”

Hydrochemical characterization of an acid mine drainage-affected reservoir: the Sancho Reservoir, Huelva, southwest Spain

“…In AMD systems, sulphate reduction to sulphide occurs at a pH of between 2 and 3 (Koschorreck et al 2003). Nevertheless, Church et al (2007) show sulphate reduction at a pH of between 4.0 and 7.5 when catalysed by anaerobic bacteria. Additionally, the anoxic conditions in the hypolimnion are associated with an increase in Fe and Mn concentrations in this zone (Fig.…”

Removal of Arsenic Using Acid/Metal-Tolerant Sulfate Reducing Bacteria: A New Approach for Bioremediation of High-Arsenic Acid Mine Waters

“…SRB grow optimally under circum-neutral conditions, therefore the AMD treatment that is mediated by SRB requires pH neutralization. However, many researchers have studied acid-tolerant and acidophilic SRB [21,36,[37][38][39][40]. Kimura, et al [41] have reported a reduction of sulfate at pH 3.8, and Bijmans, et al [42] reported a high rate of sulfate reduction at pH 4.0 and 4.5 using H2 and formate as electron donors in laboratory experiments.…”