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TitleAssessing and reducing human health risks from arsenic-rich gold mine tailings in Nova Scotia, Canada
AuthorParsons, M; Jamieson, H; Walker, S; Corriveau, M; Hall, G; Vaive, J; Little, M
Source5th SETAC (Society of Environmental Toxicology and Chemistry) World Congress, 2008 abstracts volume; 2008, 1 pages
Alt SeriesEarth Sciences Sector, Contribution Series 20070555
Meeting5th SETAC (Society of Environmental Toxicology and Chemistry) World Congress; Sydney; AU; August 3-7, 2008
ProvinceNova Scotia
AreaMontague; Goldenville
Subjectssoils science; environmental geology; geochemistry; Health and Safety; soils; soil studies; arsenic; tailings; tailings analyses; gold; mineralization; arsenopyrite; scorodite; environmental impacts; environmental studies; environmental analysis; human health
ProgramEnvironment and Health
AbstractRecent studies of 15 historical gold districts in Nova Scotia have identified several areas where exposure to mine wastes may represent a risk to human health. Arsenopyrite (FeAsS) occurs naturally in the ore and surrounding bedrock in these gold deposits, and was concentrated in the tailings during milling operations. Two sites, Montague and Goldenville, are of particular concern as the tailings are located close to residences and are occasionally used for racing off-road vehicles. This study examines the concentration and solid-phase speciation of arsenic (As) in tailings, airborne particulates, and forest soils near these sites to clarify the spatial extent of mine tailings, the mineral hosts for As, and the fate of windblown tailings dusts. Arsenic concentrations in 99 tailings samples collected from 2003-2005 range from 686 to 209,000 mg/kg (median 9120 mg/kg). These results led the Province of Nova Scotia to warn the public of potential health risks at these sites in 2005 via letters to local residents, press releases, and signage at the mines. Mineralogical characterization of the tailings and windblown dusts show that As is hosted in arsenopyrite and a variety of weathering-related phases including scorodite (FeAsO4•2H2O), Ca-Fe arsenates, and As bound to Fe oxides. These phases have varying solubilities that strongly influence the environmental fate and bioaccessibility of As in the tailings. Samples of surface soil (0-5 cm) collected within the mine districts, but away from tailings, show naturally elevated levels of As that exceed the 12 mg/kg Canadian Soil Quality Guideline for As. Environmental Site Assessments were initiated at Montague and Goldenville in Fall 2007 in response to these research results. Data from this study are presently being used to evaluate the human health risks associated with exposure to As-bearing mine tailings, and to help guide management actions to reduce exposure to these historical mine wastes.