1. Trends in diazinon and other urban pesticides in stream samples from the northeastern United States, 1993-2004 1 US Geological Survey, Troy NY 2 US Geological Survey, Baltimore MD Contact: pjphilli@usgs.gov P. J. Phillips 1, S. W. Ator 2, E. A. Nystrom 1

2. Why should we be concerned about Diazinon? One of the most frequently detected pesticides in urban streams One of the most frequently detected pesticides in urban streams Widely used lawn insect control Widely used lawn insect control Concentrations exceeded benchmark levels for protection of aquatic life Concentrations exceeded benchmark levels for protection of aquatic life

3. Diazinon/Chlorpyrifos Phaseout Began in 2002 Began in 2002 Completed in Completed in 2004 2004 From Schreder and Dickey, 2005

4. Pesticides Included In Trend Analysis INSECTICIDES INSECTICIDES Diazinon, Chlorpyrifos (decreasing) Diazinon, Chlorpyrifos (decreasing) Carbaryl (increasing?) Carbaryl (increasing?) Malathion (no change) Malathion (no change) HERBICIDES HERBICIDES Prometon, Simazine (no change) Prometon, Simazine (no change)

5. NAWQA Trends Network in Northeast US 20 sites used to analyze Diazinon trends

6. Diazinon From Urban Sources

7. Apparent Decreasing Trends for Diazinon, Chlorpyrifos Concentrations at Accotink Creek, Virginia

8. Diazinon Decreased after Phaseout

9. Chlorpyrifos Decreases, Carbaryl has no change

10. No Step Trends in Herbicides

11. Comparison of Step Trends at 20 Sites

12. Decrease in Exceedence of Diazinon Chronic Benchmark Level

13. Changes Due to Phase Out Diazinon Decreases of 50% or more during summer Diazinon Decreases of 50% or more during summer Near-elimination of chlorpyrifos Near-elimination of chlorpyrifos No change in Carbaryl No change in Carbaryl No evidence of regional herbicide changes No evidence of regional herbicide changes

14. Future Questions Will we see improvement in urban aquatic communities? Will we see improvement in urban aquatic communities? What is replacing Diazinon? What is replacing Diazinon? Not Carbaryl in Northeast Not Carbaryl in Northeast Imidacloprid? Pyrethroids? Imidacloprid? Pyrethroids? Will we be able to see further changes? Will we be able to see further changes?

15. Acknowledgements Data collected by NAWQA Study Units