Publication Summary

Pesticide concentrations were characterized at four sites in Padden Creek in Bellingham from April to June, 2001. The pesticide monitoring was part of a larger effort by the Washington State Department of Ecology, Western Washington University, and the City of Bellingham to evaluate water quality conditions in the Padden Creek watershed and identify areas of concern, as well as educate the public and focus on other pollution control efforts.

Pesticide concentrations were characterized at four sites in Padden Creek in Bellingham from April to June, 2001. The pesticide monitoring was part of a larger effort by the Washington State Department of Ecology, Western Washington University, and the City of Bellingham to evaluate water quality conditions in the Padden Creek watershed and identify areas of concern, as well as educate the public and focus on other pollution control efforts.

Eighteen of 207 targeted pesticides were detected at four sample sites during four sampling events. Two sampling events occurred during rainfall and runoff conditions while streamflows were rising and/or falling, and the other two occurred during stable streamflow conditions and well after rainfall had ceased.

The seven most frequently detected pesticides were dichlobenil, diuron, diazinon, MCPP (Mecoprop), 2,4-D, trichlopyr, and pentachlorophenol. Each of these seven pesticides was found at least once at each sample site during the study. Other pesticides detected were dicamba, simazine, prometon, chlorothalonil, MCPA, lenacil, 4-nitrophenol, terbutylazine, atrazine, and 2,3,4,6-tetrachlorophenol. A breakdown product of dichlobenil, 2,6-dichlorobenzamide, was also detected. The concentrations of most detected pesticides in Padden Creek were low, being at or slightly above detection limits. Two compounds, diazinon and chlorothalonil (Daconil), exceeded criteria for the protection of aquatic life.

Link to EIM data for User Study ID KESE0002