title: Characterization of colloidal arsenic at two abandoned gold mine sites in Nova Scotia, Canada, using asymmetric flow-field flow fractionation-inductively coupled plasma mass spectrometry.
abstract: Asymmetric flow-field flow fractionation-inductively-coupled plasma-mass spectrometry was used to determine whether colloidal arsenic (As) exists in soil pore water and soil extract samples at two arsenic-contaminated abandoned gold mines (Montague and Goldenville, Nova Scotia). Colloidal arsenic was found in 12 out of the 80 collected samples (=15%), and was primarily associated with iron (Fe) in the encountered colloids. The molar Fe/As ratios indicate that the colloids in some samples appeared to be discrete iron-arsenic minerals, whereas in other samples, they were more consistent with As-rich iron (oxy)hydroxides. Up to three discrete size fractions of colloidal As were encountered in the samples, with mean colloid diameters between 6 and 14nm. The pore water samples only contained one size fraction of As-bearing colloids (around 6nm diameter), while larger As-bearing colloids were only encountered in soil extracts.
authors.affiliation: Environmental and Life Sciences Graduate Program(⁎⁎⁎).
authors.forename: Kathryn J
authors.initials: KJ
authors.lastname: Tindale
authors.affiliation: School of the Environment, Department of Chemistry and Water Quality Centre, Trent University, Peterborough, ON K9L 0G2, Canada.
authors.forename: Pritesh J
authors.initials: PJ
authors.lastname: Patel
authors.affiliation: School of the Environment, Department of Chemistry and Water Quality Centre, Trent University, Peterborough, ON K9L 0G2, Canada. Electronic address: dwallsch@trentu.ca.
authors.forename: Dirk
authors.initials: D
authors.lastname: Wallschläger
mesh_terms: D001151:Arsenic / Q000737:chemistry*; D003102:Colloids / Q000737:chemistry; D031521:Fractionation, Field Flow; D006046:Gold; D008906:Mining; D009674:Nova Scotia; D012989:Soil Pollutants / Q000737:chemistry*
chemical_list: D003102:Colloids; D012989:Soil Pollutants; D006046:Gold; D001151:Arsenic
keywords: Arsenic; Colloids; Gold mine tailings; ICP-MS; Nanoparticles; Nova Scotia