Airborne Contaminants Found in Western U.S. and Alaskan National Parks
The Western Airborne Contaminants Assessment Project (WACAP), a six-year, multi-agency study funded primarily by the National Park Service, was initiated to determine the risk from airborne contaminants to ecosystems and food webs in eight core parks: six west coast and Alaska national parks (Sequoia, Mount Rainier, Olympic, Denali, Gates of the Arctic, Noatak) and two parks in the Rocky Mountains (Rocky Mountain and Glacier). Analysis of the concentration and biological effects of airborne contaminants in air, snow, water, sediment, lichen, conifer needles, and fish was conducted from 2002 through 2007. Atmospheric transport patterns were also assessed in order to identify potential sources of contaminants to parks. Air and vegetation samples were also collected at twelve secondary parks (Bandelier, Big Bend, Crater Lake, Glacier Bay, Grand Teton, Great Sand Dunes, Katmai, Lassen Volcanic, North Cascades, Stikine-LeConte Wilderness, Wrangell-St. Elias, and Yosemite) throughout the course of the study.
Key findings from the 8 core WACAP parks:
- Measurable amounts of both current use and historic (banned in the U.S.) contaminants were found in snow, water, vegetation, fish and lake sediment at all 8 parks;
- Parks nearest agricultural areas (Sequoia, Rocky Mountain, Glacier) contained higher levels of both currently used pesticides and pesticides banned some decades ago;
- Historical records of contaminants in lake sediments showed that the ban in the U.S. (in the 70s - 90s) of several key contaminants (e.g., DDTs, dieldrin, chlordanes) has served to reduce deposition of these compounds to lake sediments in some parks further away from agricultural sources, but they are continuing to accumulate in lake sediments of many parks close to agricultural sources;
- Contaminants generally increased with elevation, so high elevation areas in parks may be at extra risk for contamination;
- Contaminant concentrations of mercury in fish in many parks exceeded risk thresholds for health impacts to fish-eating birds and mammals, while concentrations of DDT in some fish at Sequoia and Glacier and chlordanes in one fish at Glacier exceeded risk thresholds for health impacts to fish-eating birds;
- Concentrations of mercury, dieldrin, and DDT found in fish from some parks exceeded EPA human health thresholds;
- Some "intersex" fish (male and female reproductive structures in the same fish) were found in Rocky Mountain and Glacier (but not in any of the other 6 parks in the study); and
- Some "new" contaminants like PBDEs (flame retardants commonly applied to furniture fabric) show increases in deposition to park ecosystems.
For more information and access to additional documents, fact sheets and project publications, please visit the WACAP web page.