Monitoring deep subsurface microbiota for assessment of safe long-term nuclear waste disposal

Microbes with their resistance to heat and radioactivity, if present and metabolically active, could have major effects on the safety of nuclear waste disposal by posing potential problems in long-term containment. This paper reviews the applicability of the signature lipid biomarker (SLB) analysis in the quantitative assessment of the viable biomass, community composition, and nutritional/physiological status of the subsurface microbiota as it exists in situ in subsurface samples. The samples described in this review are not unlike those expected to be recovered from proposed deep subsurface disposal sites. Assessment of the microbial community ecology using SLB analysis can be utilized to predict potential problems engendered by microbial metabolic activities of these communities in breaching containment by microbially facilitated corrosion and in the potential for subsequent facilitated transport of nuclides into the environment. SLB analysis of the in situ microbial ecology can be utilized to monitor the feasibility of containment options in modeling tests at the specific disposal sites.