Arsenic and antimony geochemistry of mine wastes, associated waters and sediments at the Giant Mine, Yellowknife, Northwest Territories, Canada

摘要: Abstract Elevated levels of arsenic (As) and antimony (Sb) in water sediments are legacy residues found downstream from gold-mining activities at the Giant Mine Yellowknife, Northwest Territories (NWT), Canada. To track transport fate As Sb, samples mine-waste mill, surface water, sediment, pore-water, vegetation mine were collected. waste, sediment analyzed for bulk chemistry, aqueous solid-state speciation. Sediment chemistry evaluated using scanning electron microscope imaging, synchrotron-based element mapping microprobe analysis. The distributions Sb similar, yet their corresponding pore-waters mostly dissimilar, mobility was greater than that Sb. Competition sorption sites is most likely cause elevated concentrations relatively oxidized pore-water water. speciation also differed. In As(V) dominated oxidizing environments As(III) reducing environments. contrast, Sb(V) species all but one sample, even under conditions. Antimony(III) appears to preferentially precipitate or adsorb onto sulfides as evidenced by prevalence an Sb(III)-S secondary solid-phase lack Sb(III)(aq) deeper zones. As(V)–O solid phase became depleted with depth below sediment–water interface, Sb(V)–O persisted surficial zone a site populated Equisetum fluviatile (common horsetail), associated organic material appeared mobile root zone. active plant growth, primarily inorganic phases suggesting release reprecipitation these elements upon death. co-existence reduced species, instability some changing redox conditions, uptake pose challenges remediation efforts mine.