Mineralogical characterization of arsenic in gold mine tailings from three sites in Nova Scotia
Chronic exposure to high concentrations of arsenic (As) in windblown and vehicle-raised dust from tailings sites in Nova Scotia poses a potential health risk to recreational users of these areas and to nearby residents. The exposure may involve inhalation of dust, as well as oral ingestion of particles. It is important to understand the mineralogy and morphology of As-bearing dust particles in order to evaluate the risk posed by near-surface particulates in As-bearing tailings fields, as this will influence the stability and toxicity of As in the wastes. Optical mineralogy, scanning electron microscopy, electron microprobe, X-ray diffraction, synchrotron-based micro-X-ray diffraction ({mu}XRD) and micro-X-ray absorption near edge structure ({mu}XANES), and sequential leach extractions were applied to tailings samples from three sites in eastern Nova Scotia. Arsenic occurs naturally in these gold deposits mainly in arsenopyrite (FeAsS). In the near-surface material of the tailings fields, sulphide minerals have almost completely oxidized to secondary minerals such as scorodite (FeAsO{sub 4}{center_dot}2H{sub 2}O) and Ca-Fe arsenates. Iron oxyhydroxides contain variable amounts of As{sub 2}O{sub 5} from trace to 30 wt.% and CaO up to 8 wt.%. The presence of multiple As-hosting solid phases, including relatively soluble Ca-Fe arsenates and Fe oxyhydroxides with adsorbed As has important implications for human health risk assessment and remediation design.
- Research Organization:
- BROOKHAVEN NATIONAL LABORATORY (BNL)
- Sponsoring Organization:
- USDOE SC OFFICE OF SCIENCE (SC)
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 1042326
- Report Number(s):
- BNL--98004-2012-JA
- Journal Information:
- Geochemistry: Exploration Environment Analysis, Journal Name: Geochemistry: Exploration Environment Analysis Journal Issue: 3 Vol. 11; ISSN 1467-7873
- Country of Publication:
- United States
- Language:
- English
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Effects of Soil Composition and Mineralogy on the Bioaccessibility of Arsenic from Tailings and Soil in Gold Mine Districts of Nova Scotia
Related Subjects
ABSORPTION
ARSENATES
ARSENIC
CHRONIC EXPOSURE
DEPOSITS
DESIGN
DIFFRACTION
DUSTS
ELECTRONS
GOLD
HAZARDS
HUMAN POPULATIONS
INGESTION
INHALATION
IRON
MATERIALS
MINERALOGY
MINERALS
MORPHOLOGY
NOVA SCOTIA
PARTICLES
PARTICULATES
RISK ASSESSMENT
SCANNING ELECTRON MICROSCOPY
SOLIDS
STABILITY
TAILINGS
TOXICITY
WASTES
X-RAY DIFFRACTION