Hostname: page-component-7c8c6479df-r7xzm Total loading time: 0 Render date: 2024-03-28T19:49:33.209Z Has data issue: false hasContentIssue false

Laboratory Examination of Microbial Perturbations in a Granitic Environment

Published online by Cambridge University Press:  21 March 2011

J. M. West
Affiliation:
British Geological Survey, Keyworth, Nottingham, Ng12 5gg, UK
K. Hama
Affiliation:
Japan Nuclear Cycle Development Institute, Tono Geoscience Centre, 959-31, Jorinji Izumi, Toki, Gifu 509-51, Japan
K. Bateman
Affiliation:
British Geological Survey, Keyworth, Nottingham, Ng12 5gg, UK
P. Coombs
Affiliation:
British Geological Survey, Keyworth, Nottingham, Ng12 5gg, UK
V. Hards
Affiliation:
British Geological Survey, Keyworth, Nottingham, Ng12 5gg, UK
A. E. Milodowski
Affiliation:
British Geological Survey, Keyworth, Nottingham, Ng12 5gg, UK
P. Wetton
Affiliation:
British Geological Survey, Keyworth, Nottingham, Ng12 5gg, UK
H. Yoshida
Affiliation:
Japan Nuclear Cycle Development Institute, Tono Geoscience Centre, 959-31, Jorinji Izumi, Toki, Gifu 509-51, Japan
Get access

Abstract

Microbial activity can have a significant impact on geochemical processes as it can influence mineral dissolution and precipitation, pH, alkalinity and redox. Experiments were conducted to study the rock-water and microbial interactions, specifically to examine the influence of microbes on the groundwater environment in fractured crystalline rock. These used combinations of crushed Äspö Diorite, Äspö groundwater with iron and sulphate reducing bacteria in columns and continuously stirred tank reactors under both anaerobic and aerobic conditions. Results showed loss (dissolution and/or mobilization) of fine grained crushed material (<50 μm) which had originally adhered to grain surfaces in the starting material. The mobilized fines were subsequently trapped on biofilms developed between grains. There was also evidence for the formation of smectite (not present in the starting materials) which, together with the trapping of translocated fines in intergranular pore throats by biofilms, resulted in blockage of the column experiments. The degree of mineralogical alteration and/or pore blocking was greater in the experiments when bacteria were present and occurred under anaerobic conditions. Little evidence for rock-water interactions was seen in the chemical analysis data for all the experiments. Modelling of the fluids showed them to be saturated with respect to clay minerals. The observed mineralogical changes seem to reflect alteration occurring in microbially mediated microenvironments close to mineral surfaces. Consequently, these changes may be too small to be detected by the chemical analysis of the bulk fluid. These experiments have shown that microbial activity can impact on fluid flow through porous media even in nutrient poor conditions. In addition, the formation of new clay minerals on pore-surfaces is potentially important for ion exchange and sorption reactions.

Type
Research Article
Copyright
Copyright © Materials Research Society 2001

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. West, J. M. and Chilton, P. J., Q. J. Eng. Geol., 30, 147154 (1997)Google Scholar
2. Pedersen, K. and Karlsson, F., SKB Technical Report 95–10 (1995)Google Scholar
3. S, Banwart (Editor), SKB Technical Report 95–26 (1995)Google Scholar
4. Bateman, K., West, J., Aoki, K., Yoshida, H., Coombs, P., Gillespie, M. R., Henney, P., Reeder, S. and Milodowski, A. E. in Scientific Basis for Nuclear Waste Management, edited by McKinley, I. G. and McCombie, C. (Mater. Res. Soc. Proc. 506, Pittsburgh, PA, 1998) pp. 10191020.Google Scholar
5. Postgate, J. R., The Sulphate Reducing Bacteria, 2nd Edition (Cambridge University Press, Cambridge, 1984)Google Scholar
6. Puigdomenech, I., Banwart, S., Bateman, K., Milodowski, A. E., West, J. M., Griffault, L., Gustafsson, E., Hama, K.. Yoshida, H, Kotelnikova, S., Pedersen, K., Lartigue, J-E., Michaud, V., Trotignon, L., Morosini, M., Perez, J. Rivas and E-L. Tullborg. Redox experiment in detailed scale (REX): First Project status report. SKB International Cooperation Report, ICR–99–01 (1999)Google Scholar
7. Adkins, J. P., Tanner, R. S., Udegbunam, E. O., Mcinerney, M. J. and Knapp, R. M., Geomicrobiol. J., 10 (2), 7786 (1992)Google Scholar