Community Research and Development Information Service - CORDIS

Risk evaluation for bioremediation of stone

Mineralogical change: some superficial anomalies due to deposition of amorphous material may occur but no serious destruction, except with very aged marble which shows some destruction of crystal structures and less cohesive properties. Preliminary tests before, and/or desalination tests after, bioremediation, may be necessary.

Visual and aesthetic change: for lighter stones, it was difficult to observe any surface change by biocalcifying bacteria. Darker stones may have lightening of the surface but surface texture was not affected. Some surfaces appeared darker after treatment but the change was not significant. High colour variation for mortar-treated areas with some increased whiteness. Bacteria in delivery system appear to have little effect on appearance, but excessively high densities of biocalcifying bacteria result in visible colour change on stone and produce a thick cracked layer. No significant colour change and no evidence of microorganisms over the long-term.

Physical properties: mortar and sepiolite may increase water uptake and porosity of limestone; Carbogel may increase water uptake and porosity or have no effect; sepiolite tends to increase water uptake and porosity; carriers do not seem to affect Gotland Sandstone. Biocalcifying bacteria decrease water absorption in Portland limestone by 1% and decrease open porosity by about 5%. Highly porous stones may not be suitable for bioremediation since salts diffuse back rapidly.

Microbial counts: actually higher in untreated areas than treated areas. No long-term consequences leading to growth of microorganisms on stone due to residual medium.

Related information

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School of Biological Sciences, King Henry I Street
PO1 2DY Portsmouth
United Kingdom
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