The chemical and physical characteristics of heavy metals in humus and till in the vicinity of the base metal smelter at Flin Flon, Manitoba, Canada |
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Authors: | P J Henderson I McMartin G E Hall J B Percival D A Walker |
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Institution: | (1) Geological Survey of Canada, 601 Booth St., Ottawa, Ontario, K1A 0E8, Canada E-mail: phenderson@gsc.nrcan.gc.ca, CA |
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Abstract: | Trace element geochemistry of humus (<0.425 mm) and till (<0.002 mm) collected in the Flin Flon-Snow Lake area, northern
Manitoba and Saskatchewan, provides a regional context for assessing smelter contamination in the environment. The area includes
a Cu-Zn smelter known to discharge As, Cd, Cu, Fe, Hg, Pb, and Zn. In this study, sequential extraction analyses, scanning
electron microscopy and x-ray diffraction analyses were used on a suite of samples to determine: (1) the chemical and physical
characteristics of heavy metals in surficial sediments related to distance from the smelter, (2) criteria for assessing the
relative contribution of these metals from natural and anthropogenic sources, and (3) the potential of these metals for remobilization
in the environment.
Humus geochemistry reflects the anthropogenic and natural component of heavy metal concentrations. Smelter-related elements
show anomalously high values adjacent to the smelter, decreasing with distance until background values are reached at 70–104 km,
depending on the element. In humus, Zn is associated primarily with labile phases; Hg with non-labile phases. Adjacent to
the smelter, high proportions and concentrations of Zn and Hg in non-labile phases, indicative of smelter-derived particulates,
are confirmed by SEM examination. The particles occur as spheres, irregular grains, and with organics. With increasing distance
from the smelter, the geochemical response to bedrock composition is more obvious than the anthropogenic input.
Till geochemistry reflects the natural variation imposed by bedrock composition. At highly contaminated sites (<3 km from
the smelter), increased percentages of smelter-related elements in labile phases suggests heavy metals are leached from humus
to the underlying sediment.
Received: 5 November 1996 · Accepted: 31 March 1997 |
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Keywords: | Heavy metals Base metals Smelter Anthropogenic contamination Chemical partitioning Soil Particulate emissions |
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