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Lenwood W. Hall, Jr. Ronald D. Anderson William D. Killen University of Maryland

Summary of Case Studies Designed to Determine the Influence of Multiple Stressors on Benthic Communities in Urban California Streams. Lenwood W. Hall, Jr. Ronald D. Anderson William D. Killen University of Maryland Wye Research and Education Center Queenstown, Maryland And

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Lenwood W. Hall, Jr. Ronald D. Anderson William D. Killen University of Maryland

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  1. Summary of Case Studies Designed to Determine the Influence of Multiple Stressors on Benthic Communities in Urban California Streams Lenwood W. Hall, Jr. Ronald D. Anderson William D. Killen University of Maryland Wye Research and Education Center Queenstown, Maryland And Raymond W. Alden III Northern Illinois University

  2. Background • Pyrethroids are insecticides used in urban areas for structural pest control, landscape maintenance and residential home and garden use • Pyrethroids have been reported by UC Berkeley investigators to potentially contribute to sediment toxicity in urban CA streams such Pleasant Grove Cr., Kirker Cr., Arcade Cr. and Salinas Streams based on laboratory toxicity tests with Hyalella • Pyrethroids are not the only possible stressor in urban streams because impaired habitat, metals and other contaminants may also be stressors

  3. Objectives • Characterize benthic communities and physical habitat annually in Pleasant Grove Cr. (2006-2008), Kirker Cr. (2006-2007), Arcade Cr. (2009-2011) and Salinas streams (2009-2011) • Concurrently measure water quality, sediment parameters, pyrethroids, and metals • Assess the relationship between benthic metrics and the various stressors based on multiple years of data

  4. California Study Areas

  5. Kirker Cr. Pleasant Grove Cr. Arcade Cr. Salinas Streams

  6. Methods • Temperature, pH, salinity, specific conductivity, DO and turbidity were measured at each site • Grain size (Plumb, 1981) and TOC (USEPA, 2004) were measured at each site • Sediment composited from 3 to 5 deposition areas (top 2-3 cm) were used for chemical and texture analysis • 75 m reach based on bioassessment protocols was the defined sample site

  7. Physical Habitat Metrics(Harrington and Born, 2000) • Epifaunal Substrate/Available Cover • Embeddedness • Velocity/Depth/Diversity • Sediment Deposition • Channel Flow Status • Channel Alteration • Frequency of Riffles/Bends • Bank Stability • Vegetative Protection • Riparian Vegetative Zone Width

  8. Epifaunal Substrate/Available Cover Embeddedness

  9. Benthic Macroinvertebrate (BMI) Sampling

  10. Methods - Continued • The following pyrethroids were measured : Bifenthrin Cypermethrin Cyfluthrin Deltamethrin Esfenvalerate Fenpropathrin Lambda – cyhalothrin Permethrin

  11. Methods - Continued • The following bulk metals were measured using EPA method 6020m: As, Cd, Cr, Cu, Pb, Ni, and Zn. • Hg was measured using EPA method 245.7 • SEM was conducted on all metals except As • AVS was also evaluated to develop SEM/AVS ratios (ratios > 1 are bioavailable and may be toxic)

  12. Total Metals Sediment Threshold Effect Levels (TELs)

  13. Methods - Continued • Univariate and stepwise multiple regression techniques were used to determine relationships between 14 benthic metrics and habitat metrics, pyrethroids, and metals

  14. Mean Total Physical Habitat Scores for Urban CA Streams for 2006-2011 (Maximum Score = 200)

  15. Salinas Main Canal at the 2994 m Transect

  16. Salinas Stream Dirty Diaper

  17. Number of BMI Taxa for Urban CA Streams (2006-2011)

  18. Five Most Dominant Benthic Taxa Pleasant Grove Cr. Kirker Cr.

  19. Five Dominant BMI Taxa Collected in Pleasant Grove Creek (2006-2008) Unid. immature Tubificidae 11.3% Micropsectra sp. 7.5% Physa sp. 7.4% Paratanytarsus sp. 6.6% Hyalella sp. 5.9%

  20. Five Most Dominant Benthic Taxa Arcade Cr. Salinas Cr.

  21. Total Number of Metal TEL Exceedances for Urban CA Streams (2006-2011; two metals with highest #s)

  22. Total Pyrethroid TUs based on Hyalella for Urban CA Streams (2006-2011)

  23. Results of stepwise multiple linear regression models of benthic metrics versus TUs for pyrethroids, habitat metrics andmetals to TEL ratios for Pleasant Grove Cr. 2006, 2007, and 2008.

  24. Results of stepwise multiple linear regression models of benthic metrics versus TUs for pyrethroids, habitat metrics andmetals to TEL ratios for Kirker Cr. in 2006 and 2007.

  25. Results of stepwise multiple linear regression models of benthic metrics versus TUs for pyrethroids, habitat metrics andmetals to TEL ratios for Arcade Creek in 2009, 2010 and 2011.

  26. Results of stepwise multiple linear regression models of benthic metrics versus TUs for pyrethroids, habitat metrics andmetals to TEL ratios for Salinas Streams in 2009, 2010 and 2011.

  27. Conclusions • Tolerant benthic taxa were dominant in all 4 CA streams but degraded communities were more apparent in Salinas streams • Habitat conditions were poor in all 4 CA streams but extremely poor in the Salinas streams • Potentially toxic concentrations of metals were frequently reported in all 4 CA streams • Sum of pyrethroid TUs based on using Hyalella suggested toxicity in 18 to 100% of the sites by year for the 4 streams

  28. Conclusions • Analysis of the 3 year data sets for Pleasant Grove Cr. showed significant relationships with benthic metrics and both habitat metrics and metals but not pyrethroids. • Analysis of the 2 year data sets for Kirker Cr. showed that habitat and metals have stronger statistical relationships with benthic metrics than pyrethroids

  29. Conclusions • Analysis of the 3 year data sets for Arcade Cr. showed more significant relationships with benthic metrics and habitat metrics than with metals or pyrethroids • Analysis of the 3 year data sets for Salinas streams showed that habitat and not metals or pyrethroids was the only stressor to show a significant relationship with benthic metrics

  30. Summary of Bioassessment Multiple Stressor Case Studies Showing Number of Significant Habitat, Metals and Pyrethroid Relationships to BMI Metrics

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