9817825 Wiegel The production of radioisotopes has resulted in large amounts of highly radioactive waste. At the Department of Energy's Savannah River Site (SRS), about 700 million curies are stored in tanks of 750,000 to 1,300,000 US gallons. It had been assumed that the high levels of radiation and the highly alkaline pH in these carbon-steel, single-shell tanks would prevent microbial growth. Bacteria were recently discovered in some corroded, leaking tanks; it is possible that some of the corrosion is due to biological processes. Life forms that can simultaneously withstand the high radioactivity, elevated temperatures, and alkaline pH in these tanks are unknown to science. In this SGER research, Juergen Wiegels, Lawrence Shimkets, and Carl Fliermans are to obtain microbial cultures from an SRS high level waste tank. They wish to show that liquid samples can be aseptically and safely collected from such tanks; that bacteria will colonize substrates (coupons) placed in the tank, and that these coupons can be safely and efficiently retrieved; that the retrieved bacteria can be cultivated, and will grow in high-radiation environments; that the cultures can be maintained in media sufficiently low in radioactivity to permit further manipulation; that 16S rDNA sequences can be obtained from these bacteria and used to characterize their phylogenetic position. Success in these activities would make what looks like one of the most unique assemblages of microbes, and one that would have significance for genetics, molecular evolution, and biodeterioration studies, available for further investigation.
