Uranium-mineralized micro-organisms associated with uraniferous hydrocarbons in southwest Scotland

Abstract

THE ability of microorganisms such as bacteria and fungi to concentrate uranium and other metals from solution has long been recognized (see, for example, refs 1–10), and has previously been applied to the economic recovery of metals from natural and industrial waste waters10–13. This phenomenon is also important in the risk assessment of radioactive waste disposal, as the mobility of microbes may either enhance or retard radionuclide migration14. Although microbiological activity has been thought to influence the deposition or remobilization of uranium in natural deposits15,16, there have been only a few direct observations of naturally mineralized microbial structures17,18. During recent investigations of uranium mobilization from mineralized rocks in southwest Scotland, we observed the presence of uranium-mineral-ized structures attributable to the activity of filamentous microor-ganisms. Unlike previous accounts of either artificially stained1,3,6,19 or naturally mineralized microbes17,18, the structures we describe display polymetallic mineralization, with a complex relationship between the metal species concentrated and its location in the microorganism.