Warren, L. A.. Dept. of Geology, University of Toronto, lwarren@zircon.geology.utoronto.ca
, . A.. ,

 
BACTERIALLY PROMOTED CALCITE PRECIPITATION AND ASSOCIATED CAPTURE OF METAL AND RADIONUCLIDE CONTAMINANTS
 
Bacteria are important determinants of trace metal behaviour in aqueous environments due to their abundance, ubiquity, small surface area to volume ratios, and in particular, their geochemically reactive surfaces (e.g. mineral precipitation - dissolution and contaminant scavenging reactions). These characteristics make them potentially highly effective bioremediation agents for trace elements. Microbially mediated precipitation of geochemically reactive mineral phases may provide a technique for the solid phase capture of contaminants. The objective of this work was to evaluate whether urea degradation by B. pasteurei could be coupled to calcite precipitation and associated incorporation of Sr, UO2, and Cu. Experiments were conducted in the laboratory as 24 hour batch experiments (B. pasteurei concentrations equivalent to an OD600 = 0.4) with total contaminant concentrations of 10-3M and compared to abiotic (no bacteria) and bacteria (no contaminants) controls. Total and dissolved element concentrations and pH were monitored over the 24 hour period. Samples were also taken for transmission electron microscopy (TEM) and energy dispersive-Xray spectroscopy (EDS) analyses and atomic force microscopy (AFM). Bacterial promotion of calcite precipitation was rapid (< 3 hours) and occurred both directly at the cell surface as well as in bulk solution with significant associated solid phase capture of the three elements. SS28 Oral
 
Day: Friday, Feb. 5
Time: 02:45 - 03:00pm
Location: Sweeney Center
 
Code: SS28FR0245S