Contaminant retention and release by bacteriogenic iron oxides in contrasting wetland environments
THURSDAY, DECEMBER 8, 2011 - 3:30 PM TO 4:30 PM IN EIT 3142 AT THE UNIVERSITY OF WATERLOO
Abstract:
Bacteriogenic iron oxides (BIOS), composed of poorly ordered hydrous ferric oxides (HFO) intermixed with partially degraded neutrophilic Fe(II)-oxidizing bacteria and associated organic material, occur in a wide range of environments including hydrothermal sea vents, geothermal springs and wetlands. BIOS are important sorbents for a range of inorganic contaminants, and this talk will focus on the role they play in (1) the retention and release of Sr and I at a groundwater-supplied wetland in Chalk River (ON); and (2) the mobility of As in mine tailings-impacted wetlands in Montague and Goldenville (NS). The stability of BIOS under the Fe redox cycling regime that characterizes these field sites will be examined in the context of contaminant mobility, while contrasting comparative work using synthetic HFOs commonly used in the laboratory to approximate natural iron oxide assemblages will also be presented.