TP22 Assessment in Polar Ecosystems
Tuesday, 15 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(GAR-1117-736582) Assessment of risk to wildlife from fugitive dust releases along a mine transportation corridor in Alaska.

Gard, N¹, Maier, E¹, Shock, S¹, ¹ Exponent, Bellevue, WA, USA

ABSTRACT- Historical transport of ore concentrate over a 50-mile haul road from the Red Dog zinc/lead mine in northwest Alaska to a seaport has been associated with elevated metal levels in tundra habitat near the road. Food-web modeling was used to assess risks to 9 mammalian and avian receptors from exposure to 14 metals in fugitive dust releases along the road corridor and near mine facilities. For six receptors (moose, Arctic fox, Lapland longspur, common snipe, willow ptarmigan, and snowy owl), the likelihood of adverse population-level effects was considered negligible, as LOAEL-based hazard quotients were generally below 1.0 for all metals, and in many cases no greater than hazard quotients in reference areas. Voles inhabiting tundra within 10-100 m of the road had incremental risk from exposure to barium and aluminum compared to reference locations. Tundra shrews showed incremental risk from exposure to barium in these same areas. However, by 1,000 m from the road, hazard quotients were generally at or below 1.0 and/or comparable to reference area hazard quotients for both species. Population-level effects were considered unlikely given the limited distance from the road where adverse effects could occur, and given uncertainties related to aluminum and barium toxicity reference values (TRVs) and bioavailability. There was a low likelihood that over-wintering caribou may experience adverse effects from aluminum exposure, as LOAEL-based hazard quotients were about 3-fold higher than for comparable reference areas. However, based on the low proportion of the total herd that were likely to over-winter near the mine and uncertainty associated with the aluminum TRV, population-level effects were not predicted. Overall, the risk assessment found that possible adverse effects to wildlife, if occurring, would be largely restricted to receptors with localized home ranges adjacent to the road.

Key words: metals, mining, arctic, wildlife