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TitleImpact of historical gold mining activities on marine sediments in Wine Harbour, Nova Scotia, Canada
AuthorLittle, M E; Parsons, M B; Law, B A; Milligan, T G; Smith, J N
SourceAtlantic Geology vol. 51, 2015 p. 344-363, https://doi.org/10.4138/atlgeol.2015.016
Year2015
Alt SeriesEarth Sciences Sector, Contribution Series 20150150
PublisherAtlantic Geoscience Society
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf
ProvinceNova Scotia
NTS11F/04
AreaWine Harbour
Lat/Long WENS-62.0000 -61.5000 45.2500 45.0000
Subjectsenvironmental geology; mining history; mining; gold; mineral deposits; mineral occurrences; heavy metals contamination; arsenic; environmental analysis; environmental impacts; environmental studies
Illustrationslocation maps; histograms; photographs; photomicrographs; plots; tables
ProgramTools for environmental impacts and adaptation for metal mining, Environmental Geoscience
AbstractPast investigations at historical gold (Au) districts in Nova Scotia, Canada have identified elevated concentrations of arsenic (As) and mercury (Hg) in nearby sediments and waters. These metal(loid)s are derived from erosion of mineralized bedrock, and the disposal of mine tailings into the environment during early operations. The Wine Harbour gold district is located along the eastern shore of Nova Scotia, and produced 1329 kg of Au from 75 581 tonnes of crushed rock from 1862 to 1939.The gold occurs in arsenopyrite-bearing quartz-carbonate veins and was extracted using stamp milling and Hg amalgamation. Historical maps document tailings deposits near former stamp mill sites; however, the extent to which these mine wastes influence environmental quality in the adjacent marine environment is uncertain. In this study, we measured metal(loid) concentrations in tailings, marine sediments, and surface waters to assess the lateral and vertical extent of mining-related impacts on Wine Harbour. Chemical analyses of terrestrial and intertidal tailings reveal high concentrations of both As (86–196 000 mg/kg) and Hg (444–320 000 µg/kg). Analyses of marine sediments show a wide range in both As (4–568 mg/kg) and Hg (<5–7430 µg/kg) concentrations. In general, the highest metal(loid) concentrations in sediments were recorded down-gradient of stamp mill sites. Elevated concentrations were also detected in sediments underlying an active mussel aquaculture operation at the western end of the harbour. Results from this study have been used to help assess potential ecosystem and human health risks associated with historical gold mine wastes in the Wine Harbour area.
Summary(Plain Language Summary, not published)
From 1861 to the mid-1940s, gold mining in Nova Scotia generated more than 3,000,000 tonnes of tailings. Most of these tailings were discharged directly onto the surrounding land and into wetlands, streams, lakes, and the ocean. Since 2003, studies by NRCan and its partners have helped to characterize the environmental and human health hazards associated with these mine wastes. In this study, we provide the first direct evidence of the disposal of gold mine tailings into Wine Harbour during mining operations from 1862 to 1939. These results clarify the spatial extent of the tailings and the contamination of local marine sediments with high concentrations of arsenic and mercury. When combined with information from concurrent biological investigations by researchers at Environment Canada (recently submitted for publication in Marine Pollution Bulletin), these results can be used to help minimize health risks and inform land-use decisions in the Wine Harbour area.
GEOSCAN ID296818