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

Church CD, Wilkin RT, Alpers CN, Rye RO, McCleskey RB - Geochem. Trans. (2007)

Bottom Line: 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.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: US Geological Survey, California Water Science Center, 4165 Spruance Road, San Diego, CA 92101, USA. clinton.church@ars.usda.gov

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. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2-3 per thousand 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.

No MeSH data available.


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Results of microbial culturing experiments of Penn Mine sediments showing total dissolved sulfide concentrations and pH trends at low pH (near 4) and near-neutral pH.
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Figure 4: Results of microbial culturing experiments of Penn Mine sediments showing total dissolved sulfide concentrations and pH trends at low pH (near 4) and near-neutral pH.

Mentions: Bacterial cultures were prepared in an anaerobic chamber using sediments collected from the Penn Mine workings. Sulfate reduction was visually evident after approximately 1 week based upon the appearance of black precipitates of iron sulfide. Low-pH and near-neutral pH cultures were next established by spiking the primary cultures into pH-adjusted growth media. Total dissolved sulfide and pH results of these experiments are shown in Figure 4. Sulfate reduction occurred at pH 4.0 to 4.35. Sulfide concentrations up to 0.48 mg L-1 (15 μM) were observed after 60 days at pH 4.3. Higher sulfide concentrations were observed at higher pH (Figure 4b). Compared to results at pH 7, lower hydrogen sulfide concentrations at pH 4 could be related to increased toxicity of total dissolved sulfide to SRB. At pH below 7, the fully protonated form of hydrogen sulfide (H2SO) dominates, and this form is believed to be responsible for dissolved sulfide toxicity and inhibition of bacterial respiration [69]. Note that at pH 4, the sulfide concentration was insufficient to generate saturation with respect to FeS, at the ferrous iron concentration in the growth medium (~4 mg L-1) based on the observation that a black precipitate did not form.


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

Church CD, Wilkin RT, Alpers CN, Rye RO, McCleskey RB - Geochem. Trans. (2007)

Results of microbial culturing experiments of Penn Mine sediments showing total dissolved sulfide concentrations and pH trends at low pH (near 4) and near-neutral pH.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2211471&req=5

Figure 4: Results of microbial culturing experiments of Penn Mine sediments showing total dissolved sulfide concentrations and pH trends at low pH (near 4) and near-neutral pH.
Mentions: Bacterial cultures were prepared in an anaerobic chamber using sediments collected from the Penn Mine workings. Sulfate reduction was visually evident after approximately 1 week based upon the appearance of black precipitates of iron sulfide. Low-pH and near-neutral pH cultures were next established by spiking the primary cultures into pH-adjusted growth media. Total dissolved sulfide and pH results of these experiments are shown in Figure 4. Sulfate reduction occurred at pH 4.0 to 4.35. Sulfide concentrations up to 0.48 mg L-1 (15 μM) were observed after 60 days at pH 4.3. Higher sulfide concentrations were observed at higher pH (Figure 4b). Compared to results at pH 7, lower hydrogen sulfide concentrations at pH 4 could be related to increased toxicity of total dissolved sulfide to SRB. At pH below 7, the fully protonated form of hydrogen sulfide (H2SO) dominates, and this form is believed to be responsible for dissolved sulfide toxicity and inhibition of bacterial respiration [69]. Note that at pH 4, the sulfide concentration was insufficient to generate saturation with respect to FeS, at the ferrous iron concentration in the growth medium (~4 mg L-1) based on the observation that a black precipitate did not form.

Bottom Line: 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.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: US Geological Survey, California Water Science Center, 4165 Spruance Road, San Diego, CA 92101, USA. clinton.church@ars.usda.gov

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. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2-3 per thousand 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.

No MeSH data available.


Related in: MedlinePlus