ANTIMONY BIOMETHYLATION BY MIXED CULTURES OF MICROORGANISMS UNDER ANAEROBIC CONDITIONS

The volatile antimony compound trimethylantimony (TMA) was detected in headspace gases over anaerobic soil enrichment cultures spiked with p otassium antimony tartrate. The presence of TMA was variable (12 posit ives from 104 cultures) and dependent upon both the inoculum source (e nvironmental sample) and enrichment culture conditions. Positives for TMA formation were obtained with variable frequency for four of the si x soils tested and for three types of enrichment culture, designed to encourage growth of nitrate-reducing, methane-producing or fermentativ e bacteria. The identity of the volatile antimony compound produced in each of the three types of enrichment culture was confirmed by gas ch romatography-mass spectrometry and gas chromatography-atomic absorptio n spectroscopy. There was no evidence of any other volatile antimony c ompound in the headspace gases. These data suggest that the capability to generate TMA is widely distributed in the terrestrial environment and is attributable to different metabolic types of micro-organisms. ( C) 1998 John Wiley & Sons, Ltd.