Inorganic contaminants in Arctic Alaskan ecosystems: long-range atmospheric transport or local point sources?

The moss monitoring technique (Hylocomium splendens) for tracking environmental concentrations of atmospheric contaminants is applied to arctic Alaska. Median 1990–1992 concentrations of Pb, Cd, Cu, V, and Zn are ≤ median 1990 concentrations in northernmost parts of the Nordic/European monitoring network. Extremely low Pb concentrations (median, 0.6 μg/g) indicate that long-range atmospheric transport (LRTAP) of Pb to arctic Alaskan ecosystems is neglible. However, samples taken adjacent to a local source point (the Dalton Highway) have elevated Pb, V, and Cu. Site-specific watershed studies indicate that natural within- and between-site variability does not affect the interpretation of our Alaskan data relative to the Nordic/European network for Pb, V and Cu. Variability is greater relative to regional data for Cd and Zn, but neither LRTAP nor the Dalton Highway appear to be significant contributors to local concentrations of Cd and Zn. Pilot studies of blueberries and other selected wildlife forage foods indicate that concentrations inH. splendens are generally comparable to those in a common carbou forage lichen, but thatH. splendens may underestimate Cu and overestimate Pb, Hg, and in some cases Cd, relative to selected forage fruits. More studies of contaminants in arctic Alaskan forage foods are needed to characterize potential exposure of human and wildlife populations to airborne contaminants in this region.