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. ( ), Kirker Cr. ( ), Arcade Cr. ( ) and Salinas streams ( )
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

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

12. 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)

13. Total Metals Sediment Threshold Effect Levels (TELs)
TEL (ug/g) As
5.9 Cd
0.596 Cr
37.3 Cu
35.7 Pb 35 Hg
0.174 Ni 18 Zn
123

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

15. Mean Total Physical Habitat Scores for Urban CA Streams for 2006-2011 (Maximum Score = 200)
Year
Mean Score all Sites
Pleasant Grove Cr.
2006 89
2007 98
2008 91
Kirker Cr. 85 66
Arcade Cr.
2009
107
2010
105
2011
106
Salinas Streams 46 54 56

16. Salinas Main Canal at the 2994 m Transect

17. Salinas Stream Dirty Diaper

18. Number of BMI Taxa for Urban CA Streams (2006-2011)
Year
# of Taxa
Pleasant Grove Cr.
2006
142
2007
145
2008
153
Kirker Cr.
110
114
Arcade Cr.
2009
101
2010 92
2011
Salinas Streams 76 68 71

19. Five Most Dominant Benthic Taxa
Pleasant Grove Cr.
Kirker Cr.
Taxon
Total %
Cyprididae
17.5
Physa sp.
16.9
Micropsectra sp.
10.7
Tubificidae unid. Imm.
10.5
Tubificidae w/hair
6.9
Taxon
Total %
Tubificidae unid.
Immature
11.3
Micropsectra sp.
7.5
Physa sp.
7.4
Paratanytarsus sp.
6.6
Hyalella sp.
5.9

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

21. Five Most Dominant Benthic Taxa
Arcade Cr.
Salinas Cr.
Taxon
Total %
Tubificidae unid.
Immature
12.6
Nais communis/
variabilis
11.5
Eukiefferiella
9.4
Cricotopus 6
Rheocricotopus sp.
5.6
Taxon
Total %
Tubificidae unid.
Immature
20.4
Nais communis/
variabilis
9.8
Pisidium
8.8
Dugesia tigrina
Physa
6.8

22. Total # TEL Exceedances
Total Number of Metal TEL Exceedances for Urban CA Streams ( ; two metals with highest #s)
Stream
Year
Total # TEL Exceedances
Pleasant Grove Cr.
2006
20 (Zn,Cu)
2007
16 (Zn,Cu)
2008
23(Zn,Cu)
Kirker Cr.
36(As,Ni)
34(As,Ni)
Arcade Cr.
2009
22(Ni,Cr)
2010
32(Ni,Cr)
2011
20(Ni,Cr)
Salinas Streams
54(Ni,As)
40(Ni,As)
31(Ni,As)

23. Total Pyrethroid TUs based on Hyalella for Urban CA Streams (2006-2011)
Year
% Sites TUs > 1
Range of TUs
Pleasant Gr. Cr.
2006 43
2007 48
2008 62
Kirker Cr. 36 57
Arcade Cr.
2009 18
2010 45
2011 55
Salinas Streams 85
100

24. Significant Variables
Results of stepwise multiple linear regression models of benthic metrics versus TUs for pyrethroids, habitat metrics and metals to TEL ratios for Pleasant Grove Cr. 2006, 2007, and 2008.
Benthic Metrics
Significant Variables
Taxonomic Richness
+ % Gravel, + Pb to TEL, - Cd to TEL
% Dominant Taxa
-Pb to TEL, +Cd to TEL
Ephemeroptera Taxa
+ Vel/depth, + Riparian buffer
EPT Taxa
+Vel/depth
EPT Index (%)
+ Vel/depth
Shannon Diversity
- Veg Protection
Tolerance Value
- Vel/depth
% Tolerant Taxa
- Vel/depth, +Cd to TEL, - Riparian buffer, + As to TEL
% Collectors/Filterers
% Collectors/Gatherers
% Grazers
+As to TEL
% Predators
- Channel alteration

25. Significant Variables
Results of stepwise multiple linear regression models of benthic metrics versus TUs for pyrethroids, habitat metrics and metals to TEL ratios for Kirker Cr. in 2006 and 2007.
Benthic Metrics
Significant Variables
Taxonomic Richness
+ Freq Riffles/Bends, - Veg Protection
Ephemeroptera Taxa
+ Cr to TEL
Tolerance Value
+ Cypermethrin
% Tolerant Taxa
- Freq riffles/bends
% Collectors/Filterers
- % Fines
% Predators
+Cr to TEL
% Shredders
- Sediment deposition, - Ni to TEL
Adundance (#/sample)
- Pb to TEL, - % Canopy cover

26. Significant Variables % Collectors/Gatherers
Results of stepwise multiple linear regression models of benthic metrics versus TUs for pyrethroids, habitat metrics and metals to TEL ratios for Arcade Creek in 2009, 2010 and 2011.
Benthic Metrics
Significant Variables
Taxonomic Richness
- Total Pyrethroid TUs
% Dominant Taxa
+ Total Pyrethroid TUs
Ephemeroptera Taxa
+Freq Riffles/Bends
EPT Taxa
+Embeddedness
EPT Index (%)
+ Embeddedness
Shannon Diversity
- Zn to TEL
Tolerance Value
+ Hg to TEL
% Tolerant Taxa
% Collectors/Gatherers
- Embeddedness
% Grazers
- Riparian veg zone
% Predators
+ Pb to TEL

27. Significant Variables % Collectors/Gatherers
Results of stepwise multiple linear regression models of benthic metrics versus TUs for pyrethroids, habitat metrics and metals to TEL ratios for Salinas Streams in 2009, 2010 and 2011.
Benthic Metrics
Significant Variables
% Collectors/Gatherers
- Sediment Deposition
% Grazers
+ Sediment Deposition

28. 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

29. 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

30. 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

31. Stream Years & # of samples Habitat Metals Pyrethroids
Summary of Bioassessment Multiple Stressor Case Studies Showing Number of
Significant Habitat, Metals and Pyrethroid Relationships to BMI Metrics
Stream
Years &
# of samples
Habitat
Metals
Pyrethroids
Pleasant Gr. Cr.
(n = 63) 12 7
Kirker Cr.
(n = 28) 6 4 1
Arcade Cr.
( n = 33) 5 3
Salinas Streams
(n = 39) 2
All streams
(n = 163) 25 15