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Airborne contamination of North American western
mountain ecosystems: evidence for concern and an approach to
evaluate risk
Authors:
D. H. Landers, USEPA, NHEERL, Western Ecology
Division, 200 SW 35th Street, Corvallis, OR, USA, 97333,
Tamara Blett, National Park
Service, Air Resources Division, Denver, CO, USA,
J. Stoddard, USEPA,
NHEERL, Western Ecology Division, 200 SW 35th Street,
Corvallis, OR, USA, 97333,
D. Muir, Environment
Canada, CCIW, Burlington, Ontario, Canada,
Chris Shaver, National
Park Service, Air Resources Division, Denver, CO, USA
Abstract: High elevation ecosystems in the western USA are receiving
deposition of persistent bioaccumulative toxicants with origins in
North America and elsewhere in the Northern Hemisphere. We sampled
late spring snow pack in two montane watersheds (2207 and 3495
m.a.s.l.) located on opposite sides of the Sierra Nevada divide in
April 1992, to evaluate organic contaminant loadings. Clean field
sampling techniques were used and the samples were analyzed for a
broad suite of organohalogen contaminants. Results suggest that
not only is the Sierra receiving deposition of these materials but
also that concentrations of the more volatile constituents (e.g.
HCH, Endosulphan) appear to increase with elevation. The National
Park Service in cooperation with the USEPA and other agencies and
universities is implementing an interdisciplinary Western Airborne
Contaminants Assessment Program that is focused in six National
Parks from the Arctic to California and East to the Rocky
Mountains. This effort will evaluate elevation and latitude
gradients with respect to airborne contaminants in lakes and their
catchments. A broad suite of organic compounds and heavy metals
will be analyzed in seven matrices. An integrated sampling design
will maximize the potential for risk evaluation at various
temporal and spatial scales.
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