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TitleFactors affecting methylmercury levels in surficial tailings from historical Nova Scotia gold mines
AuthorWinch, S; Fortin, D; Lean, D R S; Parsons, M
SourceGeomicrobiology Journal vol. 25, 2008 p. 112-129,
Alt SeriesEarth Sciences Sector, Contribution Series 20080357
PublisherInforma UK Limited
Mediapaper; on-line; digital
File formatpdf
ProvinceNova Scotia
NTS11D/11; 11F/04
AreaLake Catcha; Gold Brook; Gold Brook Lake; Seal Harbour
Lat/Long WENS-63.2042 -63.1919 44.7400 44.7319
Lat/Long WENS-61.5792 -61.6417 45.2083 45.1583
Subjectsenvironmental geology; geochemistry; hydrogeology; tailings; tailings disposal; tailings analyses; tailings geochemistry; gold; mercury; bacteria; environmental analysis; environmental studies; heavy metals contamination; mining methods; mining history; lake water geochemistry; stream water geochemistry; water analyses; water geochemistry; methylmercury
Illustrationsgeochemical profiles; location maps
ProgramEnvironment and Health
AbstractLarge quantities of Hg remain in tailings dumps from historical Nova Scotian gold mines. Depth profiles of total Hg (HgT) and methylmercury (MeHg) were compared with geochemical and microbiological variables, to identify factors influencing MeHg levels in tailings. HgT and MeHg were highly variable in tailings (0.2 - 73.5 µmol kg-1 and < dl-56.4 nmol kg-1, respectively), and were influenced by a complex set of in situ factors. Elevated MeHg was linked with > 5 µmol kg-1 HgT, organic matter, hydrology, abundance and activity of sulfate reducing bacteria, and demethylation processes. Methylmercury levels in tailings from a wet, bog-like site appeared to undergo seasonal fluctuations, with higher concentrations measured in September and October, and lower concentrations in May. Evaluations of amalgamation tailings should examine MeHg and HgT transport out of low-lying, saturated tailings dumps after snowmelt and major rainfall events, and should take into account the possibility of seasonal variation in MeHg levels in northern regions.