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TitleCharacterization of metal(loids) in mineral dusts from gold mine tailings
AuthorCorriveau, M C; Jamieson, H E; Parsons, M B; Campbell, J L
SourceGAC-MAC-CSPG-CSSS Halifax 2005, building bridges - across science, through time, around the world: abstracts/AGC-AMC-SCGP-SCSS Halifax 2005, Jeter des ponts entre les disciplines scientifiques, les époques, et unifier le monde : recueil des résumés; GAC-MAC-CSPG-CSSS Joint Meeting, Abstracts vol. 30, 2005 p. 36
Year2005
Alt SeriesEarth Sciences Sector, Contribution Series 2004428
MeetingHalifax 2005: GAC-MAC-CSPG-CSSS - AGC-AMC-SCGP-SCSS; Halifax, NS; CA; May 15-18, 2005
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf
Subjectsenvironmental geology; geochemistry; mines; mine waste products; tailings; tailings disposal; mercury; arsenic; gold; mine dust surveys; x-ray diffraction; x-ray diffraction analyses; x-ray emission spectroscopy; mineralization, secondary
ProgramMetals in the Environment (MITE)
AbstractMine tailings can represent a significant source of potentially hazardous dust. Metal(oid)s such as arsenic and mercury, can exist at relatively high concentrations in the windblown and vehicle-raised dust from these tailings. This dust poses a potential health risk to recreational users of these areas and nearby residents who are chronically exposed to tailings-derived dust. The exposure may involve inhalation of dust, as well as oral ingestion of particles into the gut, especially by children. Preliminary studies from 15 abandoned gold mine sites in Nova Scotia have indicated a significant enrichment of Hg and As in tailings-rich soils: Hg <5 ng/g to 350 µg/g; and As 9 µg/g to 31 wt.%. Mercury was used for amalgamation and may be in the form of elemental Hg, various secondary Hg phases, or may be adsorbed to mineral surfaces. Arsenic occurs naturally in these gold deposits primarily as arsenopyrite, but X-ray diffraction results show that secondary minerals such as scorodite (FeAsO4.2H2O) are abundant in the tailings. Given the variable solubility of As-bearing secondary minerals, it is critical to understand the speciation of As in the tailings in order to assess the bioavailability of ingested or inhaled particles. Particle size is also important in determining bioavailability. Particles with diameters less than about 10 µm are of particular importance because they can be inhaled into the lungs. Those less than 2.5 µm in diameter are thought to be the best indicator of inhalation health risks. Air-borne dust from several tailings fields have been collected via a Proton Induced X-ray Emission Spectroscopy (PIXE) Cascade Impactor (PCI) sampler, which collects aerodynamically fractionated particulate samples in ten
diameter ranges (>16 to 0.06 µm). Each fraction was then analyzed by PIXE in order to determine micrograms of trace element per square
centimeter (µg/cm2). Bulk tailings samples from each site were also dry sieved to examine the relationship between particle size and total
metal(loid) concentrations. Preliminary analytical results obtained by Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) after
aqua regia digestion demonstrate that metal(oid) concentrations are always higher in the <38 µm fraction than the bulk tailings samples.
However, PIXE results indicate that the relationship between As content and particle size is more complicated in the <10 µm fractions.
GEOSCAN ID220319