Bacterial Formation of Tooeleite and Mixed Arsenic(III) or Arsenic(V)−Iron(III) Gels in the Carnoulès Acid Mine Drainage, France. A XANES, XRD, and SEM Study

Abstract

The oxidation of Fe(II) in acid mine drainage (AMD) leads to the precipitation of Fe(III) compounds which may incorporate toxic elements, such as arsenic (As), within their structure or adsorb them at their surface, thus limiting their mobility. The present work provides evidence for spatial and seasonal variations of microbial activity that influence arsenite oxidation and As immobilization in the heavily contaminated AMD from the Carnoulès mine, Gard, France ([As III] = 80 to 280 mg x L(-1) in the acidic spring draining the waste-pile). In the first tens of meters of the AMD, the rapid oxidation of Fe(II) leads to the coprecipitation of large amounts of As with Fe(III) in bacterial mats. XRD, XANES, and SEM analyses of sediments and stromatolite samples revealed the unusual formation of As(III)-rich compounds, especially nanocrystalline tooeleite, Fe6(AsO3)4(SO4)(OH)4 x 4H2O, a rare ferric arsenite sulfate oxy-hydroxide mineral, together with XRD-amorphous mixed As(III)/As(V)-Fe(III) oxy-hydroxide compounds. In the wet season, the suspended sediments of the upstream zone essentially consist of tooeleite associated with am-As(III)-Fe(III) oxy-hydroxides, while am-As(V)-Fe(III) oxy-hydroxides, having As:Fe molar ratios as high as 0.6-0.8, dominate in the dry season. Comparing natural and bioassay samples revealed that the formation of As(III)-rich compounds in the wet season may be related to the metabolic activity of bacterial strains able to oxidize Fe(II) but not As(III). One of these strains, having an Acidithiobacillus ferrooxidans genotype, has been isolated from the Carnoulès AMD. In contrast, the formation of As(V)-rich compounds in the dry season can be related to both biotic and abiotic oxidation of As(III) to As(V). Some Thiomonas strains isolated from the Carnoulès AMD were shown to be able to catalyze the oxidation of As(III) to As(V) in solution. Therefore, they can promote the formation of mixed As(V)-Fe(III) oxy-hydroxides, provided enough Fe(II) oxidizes. These results yield a better understanding of natural processes at this site and may help in designing efficient As-removal processes.

Characterization of Fe(II) oxidizing bacterial activities and communities at two acidic Appalachian coalmine drainage-impacted sites

“…In studies similar to the ones we present here, A. ferrooxidans has been cultured from AMD-impacted sediments , but was subsequently shown in culture-independent studies to comprise a minor fraction of Fe(II)OB-related phylotypes (Bruneel et al, 2006). The work presented here and by others suggest that organisms other than A. ferrooxidans and L. ferrooxidans may play a prominent role in oxidative precipitation of dissolved Fe(II) from AMD Hallberg and Johnson, 2003;Morin et al, 2003;Bruneel et al, 2006). Hallberg and Johnson (2003) point out that the pH of the of AMD-impacted systems may influence the composition of Fe(II)OB communities, with relatively low pH (o3.0) favoring the growth and activity of A. ferrooxidans and L. ferrooxidans, and relatively high pH (43.0) favoring the growth and activity of 'moderately acidophilic' Fe(II)OB that are phyolgenetically related to organisms that we detected in the GB and FR systems.…”

Metabolic diversity among main microorganisms inside an arsenic-rich ecosystem revealed by meta- and proteo-genomics

“…This natural process of attenuation seems to be mainly due to microbial metabolism, leading to the oxidation of iron and arsenic into Fe(III) and As(V), and their co-precipitation with sulfur. In addition, laboratory experiments suggest that bacteria belonging to Thiomonas or Acidithiobacillus genera are involved in this process in situ Casiot et al, 2003;Duquesne et al, 2003;Morin et al, 2003;Egal et al, 2009). However, 16S-based community analyses have revealed that other genera are present in this ecosystem (Duquesne et al, 2003(Duquesne et al, , 2008Bruneel et al, 2003Bruneel et al, , 2006Bruneel et al, , 2008Bruneel et al, , 2011.…”

The mineral tooeleite Fe6(AsO3)4SO4(OH)4⋅4H2O – An infrared and Raman spectroscopic study-environmental implications for arsenic remediation

“…The mineral was 3 formed in the waste dumps from primary granular pyrite and arsenopyrite minerals 4 which were disseminated in catogenic quartz diopside ores. The mineral has also been 5 found in arsenic-bearing acid mine drainage at Carnoulès creek, France [2,3] and in 6 the acid hydrometallurgy wastes in São Bento gold mine, Brazil [4]. The valance of 7 arsenic in Tooeleite was corrected from +5 to +3 recently, as determined by Morin and 8 Nishimura et al, [1,3].…”

“…The mineral tooeleite Fe 6 (AsO 3 ) 4 SO 4 (OH) 4 ·4H 2 O was discovered at the U.S. 2 Mine, Tooele Country, Utah in 1991 by Cesbron and Williams [1]. The mineral was 3 formed in the waste dumps from primary granular pyrite and arsenopyrite minerals 4 which were disseminated in catogenic quartz diopside ores.…”

“…13 14 There have been some spectroscopic studies using both infrared and Raman 15 spectroscopy of aqueous arsenite species and arsenite containing minerals [6][7][8][9]. The 16 interest in tooeleite research mainly stems from its controlling of arsenic transport in 17 acid mine drainage and its potential significance of fixing arsenic (III) in 18 hydrometallurgical processing [1,2,4]. However, no spectroscopic studies of this 19 mineral have been undertaken.…”