Variability in pesticide deposition and source contributions to snowpack in western U.S. National Parks

Environmental Science & Technology
By: , and 

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Abstract

Fifty-six seasonal snowpack samples were collected at remote alpine, subarctic, and arctic sites in eight Western U.S. national parks during three consecutive years (2003−2005). Four current-use pesticides (CUPs) (dacthal (DCPA), chlorpyrifos, endosulfans, and γ-hexachlorocyclohexane (HCH)) and four historic-use pesticides (HUPs) (dieldrin, α-HCH, chlordanes, and hexachlorobenzene (HCB)) were commonly measured at all sites, during all years. The mean coefficient of variation for pesticide concentrations was 15% for site replicate samples, 41% for intrapark replicate samples, and 59% for interannual replicate samples. The relative pesticide concentration profiles were consistent from year to year but unique for individual parks, indicating a regional source effect. HUP concentrations were well-correlated with regional cropland intensity when the effect of temperature on snow-air partitioning was considered. The mass of individual CUPs used in regions located one-day upwind of the parks was calculated using air mass back trajectories, and this was used to explain the distribution of CUPs among the parks. The percent of the snowpack pesticide concentration due to regional transport was high (>75%) for the majority of pesticides in all parks. These results suggest that the majority of pesticide contamination in U.S. national parks is due to regional pesticide use in North America.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Variability in pesticide deposition and source contributions to snowpack in western U.S. National Parks
Series title Environmental Science & Technology
DOI 10.1021/es100290q
Volume 44
Issue 12
Year Published 2010
Language English
Publisher ACS Publications
Contributing office(s) National Research Program - Central Branch
Description 7 p.
First page 4452
Last page 4458