PARENT SESSION

PT17 Assessment and Remediation of Mercury Contaminated Sites
Exhibit Hall
8:00 AM - Tuesday

(PT265) Probable Historical Atmospheric Transport of Mercury Due to Cinnabar Roasting at Black Butte Mine (BBM).

Thom, B¹, Curtis, L², Aitken, G³, Briner, W⁴, Britton, J⁵, Sandahl, J⁶, Villeneuve, D⁷, ¹ Oregon Department of Environmental Quality, Eugene, Oregon, USA² Dept. of Environmental and Molecular Toxicology, OSU, Corvallis, Oregon, USA³ Oregon Department of Environmental Quality, Eugene, Oregon, USA⁴ US Army Corps of Engineers, Portland, Oregon, USA⁵ US Army Corps of Engineers, Portland, Oregon, USA⁶ Dept. of Environmental and Molecular Toxicology, OSU, Corvallis, Oregon, USA⁷ Dept. of Environmental and Molecular Toxicology, OSU, Corvallis, Oregon, USA

ABSTRACT- The abandoned BBM intermittently mined, crushed, and roasted cinnabar in kilns for elemental mercury production from 1882 until 1969. Mercury mobilized by these activities yielded a diffuse point-source of contamination for down-gradient surface waters including the Coast Fork of the Willamette River and Cottage Grove Reservoir. Largemouth bass from Cottage Grove Reservoir contained up to 2 g mercury / g fillet. Total mercury concentrations were determined in 99 soil samples from three, roughly concentric circles up to 2.1 km from the abandoned kilns. Total mercury concentrations ranged from 2090 to 0.1 g / g soil. Ten of these soil samples were sequentially extracted with distilled water, pH 2 HCl/HOAc, 1N KOH, 12N HNO₃, and aqua regia. The first two, highly mobile fractions were rarely detected as significant percentages of total mercury. This was probably explained by leaching since the BBM was abandoned. Samples near kilns contained up to 2 mg total mercury / g soil that was 67-89% cinnabar. Soil ranged from pH 4.3 to 7.0 Samples collected near top of surrounding hills contained up to 8 g total mercury / g soil that was less than 20% cinnabar and 44-87% soluble in 1 N KOH, suggesting substantial concentrations of complexes with organic matter. These data were consistent with historical, short-range atmospheric transport of mercury in the watershed that contains BBM. Areas with highest mercury contamination were in the immediate vicinity of the abandoned kilns on the BBM site, and contained a substantial percentage of cinnabar.

Key words: Transport, Soil, Mercury, Specration