Volatile Dimethyl Polonium Produced by Aerobic Marine Microorganisms

The production of volatile polonium (Pov), a naturally occurring radioactive element, by pure cultures of aerobic marine tellurite-resistant microorganisms was investigated. Rhodotorula mucilaginosa, a carotogenic yeast, and a Bacillus sp. strain, a Gram-positive bacterium, generated approximately one and 2 orders of magnitude, respectively, greater amounts of Pov compared to the other organisms tested. Gas chromatography-inductively coupled plasma-mass spectrometry (GC-ICP-MS) analysis identified dimethyl polonide (DMPo) as the predominant volatile Po compound in culture headspace of the yeast. This species assignment is based on the exact relation between GC retention times and boiling points of this and other Group VI B analogues (S, Se, and Te). The extent of the biotic Pov production correlates exponentially with elevated particulate Po (Pop): dissolved Po (Poaq) ratios in the cultures, consistent with efficient Po bioaccumulation. Further experimentation demonstrated that some abiotic Pov generation...