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TitleEstablishing geochemical baselines in forest soils for environmental risk assessment at the Montague and Goldenville gold districts, Nova Scotia
AuthorParsons, M B; Little, M E
SourceAtlantic Geology vol. 51, 2015 p. 364-386, https://doi.org/10.4138/atlgeol.2015.017
Year2015
Alt SeriesEarth Sciences Sector, Contribution Series 20150250
PublisherAtlantic Geoscience Society
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf
ProvinceNova Scotia
NTS11D/11; 11D/12
AreaMontague; Goldenville
Lat/Long WENS-63.5333 -63.4833 44.7333 44.7000
Subjectsgeochemistry; environmental geology; mineral occurrences; mineral deposits; gold; mineralization; environmental impacts; environmental studies; environmental analysis; geochemical surveys; geochemical analyses; geochemical interpretations; Montague gold district; Goldenville gold district
Illustrationslocation maps; photographs; plots; tables
ProgramTools for environmental impacts and adaptation for metal mining, Environmental Geoscience
AbstractMine tailings at historical gold districts in Nova Scotia, Canada, contain high concentrations of arsenic (As) and mercury (Hg), which may represent a risk to ecosystems and human health. Two sites, Montague and Goldenville, are of particular concern as tailings are located close to residences and are occasionally used for racing off-road vehicles. Risk-assessment calculations require knowledge of the naturally occurring concentrations of As and Hg in soils overlying mineralized bedrock within these gold districts. In this study, we collected samples of the top 0-5 cm of surface soil (the Public Health layer) from 46 sites near Montague, and 39 sites near Goldenville. Samples of individual soil horizons (H, Ae, B, and C) were also taken from selected sites to evaluate the vertical distribution of elements in the soil profile. Results show that the concentrations of As and Hg in all soil horizons are generally higher down-ice, southeasterly, of the ore zones in both districts, reflecting glacial erosion and transport of mineralized bedrock. Analysis of the top 0-5 cm of soils shows the following ranges in As and Hg concentrations (<2 mm size fraction): Montague: As, 4-273 mg/kg (median 42 mg/kg); Hg, 72-490 ug/kg (median 164 ug/kg); Goldenville: As, 2-140 mg/kg (median 13 mg/kg); Hg, 39-312 ug/kg (median 114 ug/kg). In general, the concentrations of As are highest in the B and C horizons, whereas Hg concentrations are highest in humus (H). Results from this study have been used to assess the distribution of tailings at these sites, and to help guide risk-management decisions.
Summary(Plain Language Summary, not published)
Mine tailings at historical gold districts in Nova Scotia contain high concentrations of arsenic (As) and mercury (Hg), which may represent a risk to ecosystems and human health. Two sites, Montague and Goldenville, are of particular concern as tailings are located close to residences and are occasionally used for racing off-road vehicles. This paper describes results from soil sampling surveys carried out by NRCan in 2007 to document the naturally occurring concentrations of As and Hg in soils overlying mineralized bedrock within these gold districts. Results show that the baseline concentrations of As and Hg are highly variable, and that the natural levels of As are up to 12 times higher than the Canadian Soil Quality Guideline. These observations demonstrate the importance of establishing site-specific baseline concentrations of metals to help guide risk assessments and remediation activities at historical and modern gold mines in Nova Scotia, and at similar metal mining sites worldwide.
GEOSCAN ID296986