1) and the community compositions reflected this change in geochemical conditions. Several novel lineages were identified within the archaeal Thermoplasmatales order associated with the pyrite slump, and the Red Pool (pH 1.4) contained the only population of Acidithiobacillus. Relatively small populations of Sulfobacillus spp. and Acidithiobacillus caldus may metabolize elemental sulfur as an intermediate species in the oxidation of pyritic sulfide to sulfate. Experiments show that elemental sulfur which forms on pyrite surfaces is resistant to most oxidants; its solublization by unattached cells may indicate involvement of a microbially derived electron shuttle. The detachment of thiosulfate (S2O32-) as a leaving group in pyrite oxidation should result in the formation and persistence of tetrathionate in low pH ferric iron-rich AMD solutions. However, tetrathionate is not observed. Although a S2O32--like species may form as a surface-bound intermediate, data suggest that Fe3+ oxidizes the majority of sulfur to sulfate on the surface of pyrite. This may explain why microorganisms that can utilize intermediate sulfur species are scarce compared to Fe-oxidizing taxa at the Richmond Mine site."/>
Skip to main content

Table II Water chemistry of samples collected within the study site at the Richmond Mine 5-way area (at the 5-way, A, B, C weirs, and at the A-slump and red pool in 2001). Concentrations are reported in millimolar units.

From: Acid mine drainage biogeochemistry at Iron Mountain, California

Sample name Date T(°C) pH Total H+ Fe2+ Fe3+ FeT Eh (mV) Cu Zn SO42
99IM25-way May-99 45 0.71 740 344 31 375 708 6.2 22.4 786
OOIM15-way June-00 36 0.60 761 159 23 182 720 3.2 19.4 743
01IM15-way January-01 29 0.84 558 64 165 229 794 2.0 16.5 657
02IM15-way March-02 42 0.83 587 297 20 317 700 4.0 14.3 684
99IM2A1 May-99 38 0.85 566 360 27 387 703 6.4 16.4 824
OOIM1A1 June-00 38 0.60 688 107 9 115 705 3.1 11.5 606
01IM1A1 January-01 30 0.89 441 81 177 258 790 2.1 11.3 560
02IM1A1 March-02 42 0.83 579 269 50 319 727 4.1 14.0 665
99IM2B1 May-99 38 0.52 1167 380 41 420 713 5.4 27.9 1161
OOIM1B1 June-00 31 0.60 1000 209 61 271 738 3.5 25.3 1020
01IM1B1 January-01 27 0.75 715 55 257 312 810 1.4 25.5 929
02IM1B1 March-02 47 0.78 582 261 13 274 692 2.2 16.8 550
99IM2C1 May-99 48 0.76 805 372 30 403 705 6.0 26.8 1020
OOIM1C1 June-00 44 0.60 858 170 25 196 721 3.3 23.8 756
01IM1C1 January-01 32 0.85 503 47 195 243 806 2.0 24.1 635
02IM1C1 March-02 50 0.76 800 281 7 288 676 4.7 14.3 651
02IMM B-back March-02 45 0.83 544 240 1 241 638 2.3 17.2 586
02IM1 C-back March-02 50 0.82 583 274 12 286 689 4.5 14.2 656
00IM1 A-slump June-00 32 1.10 190 26 21 46 764 0.9 1.3 149
01IM1 A red pool January-01 30 1.38 115 10 25 35 793 0.3 2.7 142
02IMM A-back March-02 42 0.83 675 363 16 380 690 6.0 18.4 892