Metal concentrations and source apportionment of particulates at remote sites in Canada

G.J. Dias¹, G.C. Edwards¹, G. Dharwarkar¹, S. Steffen², P. Hazlewood², P.E. Rasmussen³, W.H. Schroeder²

¹ School of Engineering, University of Guelph, Guelph, ON
² Meteorological Service of Canada, Downsview, ON
³ Health Canada, Ottawa, ON

To determine the origin of particulate samples collected at Thunder Bay and Rouyn Noranda in 2000, 4 source apportionment techniques were used with the PCI data set. Preliminary results show that at TB and RN, Al, Si, Fe, Ti, Ca, Mn, K, Cr, Sr and Ni are locally-derived, likely from substrate erosion. As and Zn are also locally-derived at Thunder Bay. Cu is believed to originate from non-local sources at Thunder Bay, but was locally derived at Rouyn Noranda, although it is possible that samples collected near the soil surface could actually be deposited material that has been re-emitted. Filter pack data for the same time periods will be presented to further validate our conclusions on particulate sources.

For the Yukon 2001 study, particulate matter (PM) concentrations were high during 6 dry days (July 17-22), peaking at 2700 g/m3 for PM2.5 and 17,000 g/m3 for PM10. Average PM10 concentrations for the whole study were 128 g/m3, compared to 156 g/m3 found by gravimetric analysis of filters, showing good mass closure. Highest particulate concentrations by FP were 172 g/m3 for north under unstable conditions, and 403 g/m3 for south under stable conditions. Particulate mercury concentrations (not blank corrected) averaged 10 og/m3, in contrast to 20 pg/m3 at thunder Bay and 100 pg/m3 at Rouyn Noranda.

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Micrometeorological and chamber measurements of gaseous mercury flux in the Selwyn Basin, Yukon

G.C. Edwards¹, S. Steffen², P. Hazlewood², P.E. Rasmussen³, W.H. Schroeder² G.J. Dias¹, S. Ausma¹

₁ School of Engineering, University of Guelph, Guelph, ON
² Meteorological Service of Canada, Downsview, ON
³ Health Canada, Ottawa, ON

Field measurements of gaseous mercury were undertaken at Selwyn Basin, Yukon from July 7 to August 2, 2001. This area represents a mercuriferous shale. Continuous measurements were made using a micrometeorological and chamber technique. The micrometeorological measurements were made only on the cleared shale, while the chamber method was used to make mercury flux measurements over the shale and shale with moss.

Chamber and MM average fluxes were similar over the measurement period (9 and 7 ng/m3/s respectively for a shale substrate concentration of 350 ppb +/- 116). Vegetated surfaces (Moss) showed fluxes on the order of 1.5 ng/m3/s. A higher substrate site (i.e., 1660 +/- 444) showed fluxes of 213 ng/m3/s. The poster presents the mercuy fluxes and associated environmental data.

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Chemical speciation of some metal pollutants associated with atmospheric particulate matter of varying size using X-ray Absorption Fine Structure (XAFS)

Lamoureux, M.¹, N. Warner¹, J. Samson¹, V. MacKinnon¹, K. Lantz¹, Terry Gordon¹, G. Grégoire²

¹ Saint Mary's University, Halifax, NS,
² Geological survey of Canada, NRCan, Ottawa, ON.

XAFS measurements for copper, nickel, and lead (partially) were done on airborne particulate matter (APM) collected in February 2000 and July/August 2000. The APM were collected using a pair of high volume samplers, each equipped with a 5-stage cascade impactor (particle size cutoffs were 7.2, 3.0, 1.5, 0.95, and 0.49 m). The samplers were positioned upwind (sampler No. 1) and downwind (sampler No. 2) from a Cu smelter (Rouyn Noranda, Qc). From the XAFS measurements, chemical speciation of airborne Cu, Ni, and Pb (partially completed) was determined as a function of particle size. The speciation of airborne copper collected on stages of sampler No. 2 with larger aerodynamic diameter cutoff (e.g., stage 1 and 2) is different than that found at the smaller diameter cutoff (e.g., stage 4 and 5). The XAFS analysis shows clearly that copper sulfate is the dominant copper species on stage 4 and 5. Cu sulfate was found on stage 4 and 5 of sampler No. 2 for each collection period (i.e., February and July/August 2000). The nickel concentration for stages 1-4 of both samplers was below the detection limit for XAFS measurements and thus XAFS measurements were done only for samples from stage No. 5 of both samplers. The XAFS analysis shows that nickel oxide is the major nickel species in samples from stage No. 5 (cutoff at 0.49 m) of both samplers. Our preliminary analysis indicates the presence of lead sulfate on stage 4 and 5 of sampler No. 2, and little detectable Pb for XAFS analysis on stage 4 and 5 of sampler No.1.

The impact of our findings on ERA of metals can be summarized in the following way. The speciation results obtained using XAFS demonstrate, for example, that the Cu species on APM obtained downwind from the smelter are different from those obtained upwind. This is also consistent with ICP-MS results (total concentration and Pb ratios vs particle size, not shown) that show that the metal-containing APM obtained downwind from a Cu smelter have distinct chemical characteristics compared to those obtained upwind.

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Localization of Particulate Fallout in Soils of the Sudbury Smelter Footprint

Spiers, G.A., D. Pearson, A. Cheburkin, F. Prevost and A. Lock.

Centre for Environmental Monitoring, MIRARCo, Laurentian University, Sudbury, ON.

The metal mining and smelting industry in the Sudbury, Ontario, area began before the turn of the century, developing into one of the largest metal producing complexes in the world. The atmospheric emissions of sulphur were massive, with the area smelting complex being one of the largest point sources of SO2 emissions in the world in the early 1960's at over 2,000,000 tonnes per annum, with reductions through implementation of abatement measures to approximately 200,000 tonnes in the 1990's. As important as the SO2 emissions were the 1500 tonnes of metal particulates carried aloft annually in the hot gas plume, particulates composed primarily of minute iron-rich fly-ash spherules containing intergrowth of nickel, copper and other trace metals. The result of the atmospheric washout of this massive release was a denuded landscape with acidified soils contaminated with metals. This massive environmental insult means the Sudbury region provides an opportunistic macrocosm for mechanistic research on the effects of severe acidification and metal pollution on soils and ecosystems.

Current static pedological research initiatives are focused on describing the nature and distribution of metals and metal-rich fallout particles in the upper sola of selected regional soils. The results to be presented in this poster will focus on the morphology, mineralogy and compositional chemistry of the magnetic metal-rich fragments filtered by the LFH horizons of selected Podzolic and Brunisolic pedons within the Sudbury smelter footprint. These particles, composed of minerals such as magnetite, maghemite, and trevorite, contain varying quantities of iron, silicon, aluminium, nickel, copper, cobalt, arsenic, selenium, phosphorus and manganese.
Examples of of metal-rich magnetic particles from an LFH horizon of a pedon in the Sudbury smelter footprint:

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