Upheaval of House Foundations Damage Caused by Bacteria

3 Upheaval of House Foundations Damage Caused by Bacteria 

From the shape (rods) of the bacteria, they appear to be Acidithiobacillus ferro-oxidans but not Leptospirillum ferrooxidans. Finally, when the mixture of the mudstone and the medium for the sulfur-oxidizing bacteria (pH 6.5) supplemented with powdered pyrite is shaken in air, the pH of the culture medium is lowered over time. When the pH is lowered to below 4, the amount of ferrous ion plus ferric ion in the medium increases rapidly together with a parallel increase of sulfate ion (Yamanaka et al., 2002b). These phenomena are not observed with the mudstone heated at 121°C for 20 min. The results show that the acidophilic iron-oxidizing bacteria (growing at pH lower than about 4) oxidize pyrite but the usual sulfur- 

The experimental results obtained above show also that pyrite is not easily oxidized chemically even if it is in contact with air and water for several days, although it may be oxidized when it is exposed to similar conditions for several years or more. 

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