A study of pesticides in snow at national parks found the following amounts of pesticides in 2003. A nanogram equals 1 billionth of a gram.
Denali National Park and Preserve: amount of dacthal, a current-use pesticide, was 0.0006 to 0.036 nanograms per liter; amount of hexachlorocyclohexanes, a banned pesticide, was below 0.0006 nanograms per liter.
Gates of the Arctic National Park and Preserve: dacthal at 0.0098 nanograms, hexachlorocyclohexanes at below 0.006 nanograms.
Glacier National Park: dacthal at between 0.23 and 0.17 nanograms, hexachlorocyclohexanes at between 0.12 and 0.23 nanograms.
Mount Rainier National Park: dacthal at between 0.0097 and 0.20 nanograms, hexachlorocyclohexanes at between 0.069 and 0.11 nanograms.
Noatak National Preserve: dactahl at 0.011 nanograms, hexachlorocyclohexanes at 0.20 nanograms.
Rocky Mountain National Park: dachtahl between 1.4 and 1.5 nanograms, hexachlorocyclohexanes at between 0.079 and 0.14 nanograms.
Sequoia National Park: dachtahl at between 1.8 and 3.1 nanograms, hexachlorocyclohexanes at between 0.086 and 0.17 nanograms.
Additional background on the studies are online at www2.nature.nps.gov/air/Studies/air_toxics/wacap.cfm