1. University of Maryland Wye Research and Education Center
Mapping the Spatial Extent of Depositional Areas in Agricultural, Urban and Residential California Streams with Suspected Pyrethroid Toxicity
Lenwood W. Hall Jr.
Ronald D. Anderson
William D. Killen
University of Maryland
Wye Research and Education Center
Queenstown, Maryland

2. Peer Reviewed Publication
Hall, L. W. Jr., R. D. Anderson and W. D. Killen Mapping the spatial extent of depositional areas in agricultural, urban and residential California streams: Implications for pyrethroid toxicity. Human and Ecological Risk Assessment 18:

3. FINAL CONCLUSIONS
The spatial extent of depositional areas (<16%) was low for all three types of streams and generally more dominant downstream
Pyrethroid concentrations were greater in downstream areas except for Pleasant Grove Creek
The “representativeness” of depositional areas should be addressed for the entire stream as stated in SWAMP protocols
Spatial scale of depositional areas should be considered for 303 d listing of hydrophobic chemicals

4. Introduction
Pyrethroid insecticides are used in residential and urban areas for structural pest control, landscape maintenance, and residential home and garden use and in agricultural areas for general pest control on various agricultural crops
Pyrethroids have been identified at potentially toxic concentrations in agricultural, urban and residential streams in CA based on Hyalella toxicity tests.
Sediment for Hyalella toxicity testing and chemical analysis is collected using a targeted sampling approach in depositional areas.

5. Introduction - Continued
Depositional areas can be rare in various streams due to the presence of sandy sediment.
“Representativeness” of targeted sampling is an issue that should be addressed according to SWAMP protocols.
Pyrethroid residues at potentially toxic levels have been found in depositional areas from Del Puerto Creek (ag) , Arcade Creek (urban) and Pleasant Grove Creek (residential) resulting in 303 d listings.
Sediment sampling issues addressed in this presentation extend beyond pyrethroids

6. Objectives
Determine the spatial extent of depositional areas in agricultural, urban and residential California streams using wetted stream bed mapping
Discuss the implications of the standard sediment sampling approach and stream depositional areas with respect to pyrethroid measurements

7. California Sampling Locations
Arcade Creek
Del Puerto Creek

8. Del Puerto Creek

9. Arcade Creek

10. Pleasant Grove Creek

11. Sediment Sampling Designs
Targeted – bias worst case approach
Random – basis for many statistical tests
Stratified Random – i.e., randomly select from depositional areas as in SWAMP protocol
Model based estimation – e.g. use TOC as a covariate and sample areas covering a range

12. Sediment Mapping
Grid tool (1 x1 m) used to determine depositional and non-depositional areas by site
99 randomly selected sites from equally spaced lower, middle and upper segments (33 per segment) were evaluated
Google Earth Pro was used to identify all possible sampling grids in the site selection process

13. PGC10

14. Pyrethroid Measurements in Sediment (Morse Labs)
Bifenthrin
Cypermethrin
Cyfluthrin
Deltamethrin
Esfenvalerate
Fenpropathrin
Lambda – cyhalothrin
Permethrin

15. Pyrethroid Measurements by Stream
Del Puerto Creek – 3 random measurements from depositional and non-depositional areas for each of the 3 sections
Arcade Creek – measurements from depositional areas at 11 bioassessment sites with 3 to 5 sites per stream section
Pleasant Grove Creek – 2008 pyrethroid measurements in depositional areas from 21 bioassessment sites with 3 to 9 sites per section

16. Map showing 33 sites in lower section of Del Puerto Creek (~ 4
Map showing 33 sites in lower section of Del Puerto Creek (~ 4.5 km) with dark sections of pie chart representing the % depositional area

17. Map showing 33 sites in middle section of Del Puerto Creek (~ 4
Map showing 33 sites in middle section of Del Puerto Creek (~ 4.5 km) with dark sections of pie chart representing the % depositional area

18. Map showing 33 sites in upper section of Del Puerto Creek (~ 4
Map showing 33 sites in upper section of Del Puerto Creek (~ 4.5 km) with dark sections of pie chart representing the % depositional area

19. Mean Total Pyrethroid Concentrations By Section For Del Puerto Creek (ng/g)
Depositional
Non-Depositional

20. Summary Points - Del Puerto Creek
4% was depositional area
Depositional areas were more dominant downstream
Total pyrethroids were much higher in depositional areas vs. non-depositional areas and concentrations were much lower upstream

21. Map showing 33 sites in lower section of Arcade Creek (~ 8 km) with dark sections of pie chart representing the % depositional area

22. Map showing 33 sites in middle section of Arcade Creek (~ 8 km) with dark sections of pie chart representing the % depositional area

23. Map showing 33 sites in upper section of Arcade Creek (~ 8 km) with dark sections of pie chart representing the % depositional area

24. Total Pyrethroid Concentration by Section for Arcade Creek Sites (ng/g)
Lower Section
Middle Section
Upper Section
Arcade Creek Sites

25. Summary Points- Arcade Creek
15% was depositional area
Depositional areas were more dominant downstream
Total pyrethroids were much higher in downstream areas

26. chart representing the % depositional area
Map showing 33 sites in lower section of Pleasant Grove Creek (~ 14 km) with dark sections of pie
chart representing the % depositional area

27. chart representing the % depositional area
Map showing 33 sites in middle section of Pleasant Grove Creek (~ 14 km) with dark sections of pie
chart representing the % depositional area

28. chart representing the % depositional area
Map showing 33 sites in upper section of Pleasant Grove Creek (~ 14 km) with dark sections of pie
chart representing the % depositional area

29. Total Pyrethroids (ng/g) by Section from PGC Bioassessment Sites
PGC Sites

30. Summary Points Pleasant Grove Creek
12 % was depositional area
Total pyrethroids were much lower in the downstream section compared to the middle and upstream sections

31. FINAL CONCLUSIONS
The spatial extent of depositional areas (<16%) was low for all three types of streams and generally more dominant downstream
Pyrethroid concentrations were greater in downstream areas except for Pleasant Grove Creek
The “representativeness” of depositional areas should be addressed for the entire stream as stated in SWAMP protocols
Spatial scale of depositional areas should be considered for 303 d listing of hydrophobic chemicals

32. Summary of CA Sediment Mapping Studies
Stream
Year
# Transects
% Dep. Area
Pyrethroids
Measured
BMIs Assessed
Arcade Cr
2009 99 15 N
Del Puerto Cr.
2010 4 Y
Salinas Streams
2011 96 24
Pleasant Gr. Cr. 12
2012 5