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TitleOrganic matter control on the distribution of arsenic in lake sediments impacted by ~65 years of gold ore processing in subarctic Canada
AuthorGalloway, J M; Swindles, G T; Jamieson, H E; Palmer, M; Parsons, M B; Sanei, H; Macumber, A L; Patterson, R T; Falck, H
SourceScience of the Total Environment vol. 622-623, 2017 p. 1668-1679, https://doi.org/10.1016/j.scitotenv.2017.10.048
Year2017
Alt SeriesNatural Resources Canada, Contribution Series 20170227
PublisherElsevier
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf (Adobe® Reader®); html; docx (Microsoft® Word®); xlsx (Microsoft® Excel®)
ProvinceNorthwest Territories
NTS85I/04; 85I/05; 85I/06; 85I/11; 85I/12; 85I/13; 85J/01; 85J/02; 85J/06; 85J/07; 85J/08; 85J/09; 85J/10; 85J/11; 85J/14; 85J/15; 85J/16
AreaYellowknife; Great Slave Lake; Detah; Prosperous Lake; Prelude Lake
Lat/Long WENS-114.9817 -113.1158 62.8956 62.0672
Subjectsenvironmental geology; geochemistry; surficial geology/geomorphology; hydrogeology; mineralogy; mathematical and computational geology; lake sediment geochemistry; lake water geochemistry; arsenic geochemistry; concentration; mining; mineral processing; gold; climate effects; ecosystems; x-ray fluorescence analyses; x-ray diffraction analyses; sulphur geochemistry; sulphides; organic geochemistry; bedrock geology; lithology; igneous rocks; volcanic rocks; felsic volcanic rocks; intrusive rocks; granitic rocks; granites; metamorphic rocks; metasedimentary rocks; hydrologic environment; statistical analyses; scanning electron microscope analyses; pyrolysis; permafrost; transport mechanisms; Slave Province; Giant Mine; Con Mine; Duckfish Granite; Defeat Plutonic Suite; Prosperous Granite; Yellowknife Supergroup; Anton Complex; Burwash Formation; Jackson Lake Formation; Ingraham Formation; Townsite Formation; Crestaurum Formation; Chan Formation; organic matter; climate change; contamination; atmospheric emissions; distribution controls; principal component analysis; mineral liberation analysis; wind; rock-eval analyses; permafrost thaw
Illustrationsflow diagrams; plots; location maps; geoscientific sketch maps; rose diagrams; scatter diagrams
ProgramMetal Mining: northern baselines, Environmental Geoscience
AbstractClimate change is profoundly affecting seasonality, biological productivity, and hydrology in high northern latitudes. In sensitive subarctic environments exploitation of mineral resources led to contamination and it is not known how cumulative effects of resource extraction and climate warming will impact ecosystems. Gold mines near Yellowknife, Northwest Territories, subarctic Canada, operated from 1938 to 2004 and released > 20,000 t of arsenic trioxide (As2O3) to the environment through stack emissions. This release resulted in elevated arsenic concentrations in lake surface waters and sediments relative to Canadian drinking water standards and guidelines for the protection of aquatic life. A meta-analytical approach is used to better understand controls on As distribution in lake sediments within a 30-kmradius of historic mineral processing activities. Arsenic concentrations in the near-surface sediments range from5mg·kg(-1) to over 10,000 mg·kg(-1) (median 81mg·kg(-1); n=105). Distance and direction from the historic roaster stack are significantly (p < 0.05) related to sedimentary As concentration, with highest As concentrations in sediments within 11 km and lakes located downwind. Synchrotron-based micro-XRF and micro-XRD confirm the persistence of As2O3 in near surface sediments of two lakes. Labile organic matter (S1) is significantly (p < 0.05) related to As and S concentrations in sediments and this relationship is greatest in lakes within 11 km from the mine. These relations are interpreted to reflect labile organic matter acting as a substrate for microbial growth and mediation of authigenic precipitation of As-sulphides in lakes close to the historic mine where As concentrations are highest. Continued climate warming is expected to lead to increased biological productivity and changes in organic geochemistry of lake sediments that are likely to play an important role in the mobility and fate of As in aquatic ecosystems.
Summary(Plain Language Summary, not published)
Gold mines near Yellowknife, Northwest Territories, subarctic Canada, operated released more than 20,000 tonnes of arsenic trioxide to the environment through stack emissions. We use a meta-analytical approach to better understand controls on As distribution in lake sediments of this region. Distance and direction from historical mineral processing activities and labile organic matter are related to arsenic concentrations in lake sediments. The relationship with organic matter is interpreted to reflect organic matter acting as a substrate for microbial growth and mediation of authigenic precipitation of As-sulphides in lakes close to the historic mine. Continued climate warming is expected to affect the organic geochemistry of lake sediments that are likely to play an important role in the mobility and fate of As in aquatic ecosystems.
GEOSCAN ID306075