US EPA

1359849 

Journal Article 

The impact of gold smelter emissions on vegetation and soils of a sub-Arctic forest-tundra transition ecosystem 

Hocking, D; Kuchar, P; Plambeck, JA; Smith, RA 

1978 

Yes 

Journal of the Air Pollution Control Association
ISSN: 0002-2470 

HEEP/78/09158 

28 

2 

133-137 

HEEP COPYRIGHT: BIOL ABS. Gold smelters near Yellowknife in Canada's Northwest Territories have emitted large quantities of SO2 and Ar since inception of roasting in 1941. Although particulate wastes are well contained by baghouse filters in the 1 remaining operating smelter, significant gaseous emissions continue. Soil and vegetation were sampled at 52 sites over an area of about 40 km radius from the source. Plant ecology was studied at 43 of those sites. After preliminary multi-element screening that indicated only Ar was a serious persistent contaminant, X-ray fluorescence was used to measure Ar content in sampled materials. The plant ecology data were synthesized into an Index of Vitality with numerical ratings of pertinent factors. In the marginal forests and rocky outcrops of the area, indicator species of vegetation permitted a division into zones of severe, moderate, mild, or no impact in order of increasing distance from the current center of emissions. Severe impact, including killing of trees, is local only. Analyses of foliage indicate little uptake of Ar which, together with the presence of SO2 symptoms, point to SO2 as the main factor causing decline of vegetation. Data show a frequency of at least 2 significant fumigation episodes per growing season. Soil analyses indicate extremely high Ar contamination near the stack. A monotonic pattern of dispersion yielded a function explainable in terms of rapid condensation of gaseous emissions. The relationship of Ar in surface soil and vegetation to distance is approximately an inverse square.