Mobility and microbially mediated mobilization of gold and arsenic in soils from two gold mines in semi-arid and tropical Australia

Reith, Frank; McPhail, Derry

doi:10.1016/j.gca.2006.11.014

Cited by 43 publications

(13 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Au concentrations detected in solution (up to 200 ppb) in microcosms amended with pure Au pellets (99.99 wt%) show that microbial activity led to a doubling of Au concentrations in solution, compared to the microcosms not amended with Au (10). Similar results were also obtained in microcosms with auriferous soils from semiarid and tropical zones in Australia (44). This suggests that Au is continuously mobilized on the surface of Au grains leading to highly toxic microenvironment.…”

Section: Discussionsupporting

confidence: 81%

Mechanisms of gold biomineralization in the bacterium Cupriavidus metallidurans

Reith

Etschmann

Große

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

294

274

View full text Add to dashboard Cite

Section: Discussionsupporting

confidence: 81%

Mechanisms of gold biomineralization in the bacterium Cupriavidus metallidurans

Reith

Etschmann

Große

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

294

274

View full text Add to dashboard Cite

“…In biologically active microcosms amended with native 99.99% pure gold pellets, gold was liberated from the pellets as well as the soil, and the formation of bacterial biofilms on the gold pellets was observed; in contrast, gold was not solubilized in sterile controls (Figure 2; . Similar results were also obtained in microcosms with auriferous soils from semi-arid and tropical zones in Australia (Reith and McPhail, 2007). The solubilization of gold in the microcosms appeared to be linked to the activity of heterotrophic bacteria that dominate the bacterial communities in organic matter-rich soils.…”

Section: Microbial Mechanisms Of Gold Solubilizationsupporting

confidence: 79%

The geomicrobiology of gold

et al. 2007

View full text Add to dashboard Cite

Microorganisms capable of actively solubilizing and precipitating gold appear to play a larger role in the biogeochemical cycling of gold than previously believed. Recent research suggests that bacteria and archaea are involved in every step of the biogeochemical cycle of gold, from the formation of primary mineralization in hydrothermal and deep subsurface systems to its solubilization, dispersion and re-concentration as secondary gold under surface conditions. Enzymatically catalysed precipitation of gold has been observed in thermophilic and hyperthermophilic bacteria and archaea (for example, Thermotoga maritime, Pyrobaculum islandicum), and their activity led to the formation of gold-and silver-bearing sinters in New Zealand's hot spring systems. Sulphatereducing bacteria (SRB), for example, Desulfovibrio sp., may be involved in the formation of goldbearing sulphide minerals in deep subsurface environments; over geological timescales this may contribute to the formation of economic deposits. Iron-and sulphur-oxidizing bacteria (for example, Acidothiobacillus ferrooxidans, A. thiooxidans) are known to breakdown gold-hosting sulphide minerals in zones of primary mineralization, and release associated gold in the process. These and other bacteria (for example, actinobacteria) produce thiosulphate, which is known to oxidize gold and form stable, transportable complexes. Other microbial processes, for example, excretion of amino acids and cyanide, may control gold solubilization in auriferous top-and rhizosphere soils. A number of bacteria and archaea are capable of actively catalysing the precipitation of toxic gold(I/ III) complexes. Reductive precipitation of these complexes may improve survival rates of bacterial populations that are capable of (1) detoxifying the immediate cell environment by detecting, excreting and reducing gold complexes, possibly using P-type ATPase efflux pumps as well as membrane vesicles (for example, Salmonella enterica, Cupriavidus (Ralstonia) metallidurans, Plectonema boryanum); (2) gaining metabolic energy by utilizing gold-complexing ligands (for example, thiosulphate by A. ferrooxidans) or (3) using gold as metal centre in enzymes (Micrococcus luteus). C. metallidurans containing biofilms were detected on gold grains from two Australian sites, indicating that gold bioaccumulation may lead to gold biomineralization by forming secondary 'bacterioform' gold. Formation of secondary octahedral gold crystals from gold(III) chloride solution, was promoted by a cyanobacterium (P. boryanum) via an amorphous gold(I) sulphide intermediate. 'Bacterioform' gold and secondary gold crystals are common in quartz pebble conglomerates (QPC), where they are often associated with bituminous organic matter possibly derived from cyanobacteria. This may suggest that cyanobacteria have played a role in the formation of the Witwatersrand QPC, the world's largest gold deposit.

show abstract

“…However, the hyperaccumulation of gold is not a natural trait of plant species (Anderson et al, 1999a). Although gold can be highly mobile (Reith and McPhail, 2007), under surface environmental conditions it is insoluble and this reduces its bioavailability and limits the potential for phytoextraction; bioavailability is one of the most critical factors for plant uptake of metals (GardeaTorresdey et al, 2005).…”

Section: Gold Accumulation In Plantsmentioning

confidence: 99%