Paper No. JAWRA-10-0025-P of the Journal of the American Water Resources Association (JAWRA). Discussions are open until six months from print publication.
Trends in Pesticide Concentrations in Streamsof the Western United States, 1993-20051
Version of Record online: 6 DEC 2010
© 2010 American Water Resources Association. This article is a US Government work and is in the public domain in the USA
JAWRA Journal of the American Water Resources Association
Volume 47, Issue 2, pages 265–286, April 2011
How to Cite
Johnson, H. M., Domagalski, J. L. and Saleh, D. K. (2011), Trends in Pesticide Concentrations in Streamsof the Western United States, 1993-2005. JAWRA Journal of the American Water Resources Association, 47: 265–286. doi: 10.1111/j.1752-1688.2010.00507.x
Re-use of this article is permitted in accordance with the Terms and Conditions set out at http://wileyonlinelibrary.com/onlineopen#OnlineOpen_Terms
- Issue online: 28 MAR 2011
- Version of Record online: 6 DEC 2010
- Received March 1, 2010; accepted October 18, 2010.
- time series analysis;
- watershed management;
Johnson, Henry M., Joseph L. Domagalski, and Dina K. Saleh, 2010. Trends in Pesticide Concentrations in Streams of the Western United States, 1993-2005. Journal of the American Water Resources Association (JAWRA) 00(0):1-22. DOI: 10.1111/j.1752-1688.2010.00507.x
Abstract: Trends in pesticide concentrations for 15 streams in California, Oregon, Washington, and Idaho were determined for the organophosphate insecticides chlorpyrifos and diazinon and the herbicides atrazine, s-ethyl diproplythiocarbamate (EPTC), metolachlor, simazine, and trifluralin. A parametric regression model was used to account for flow, seasonality, and antecedent hydrologic conditions and thereby estimate trends in pesticide concentrations in streams arising from changes in use amount and application method in their associated catchments. Decreasing trends most often were observed for diazinon, and reflect the shift to alternative pesticides by farmers, commercial applicators, and homeowners because of use restrictions and product cancelation. Consistent trends were observed for several herbicides, including upward trends in simazine at urban-influenced sites from 2000 to 2005, and downward trends in atrazine and EPTC at agricultural sites from the mid-1990s to 2005. The model provided additional information about pesticide occurrence and transport in the modeled streams. Two examples are presented and briefly discussed: (1) timing of peak concentrations for individual compounds varied greatly across this geographic gradient because of different application periods and the effects of local rain patterns, irrigation, and soil drainage and (2) reconstructions of continuous diazinon concentrations at sites in California are used to evaluate compliance with total maximum daily load targets.