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Summary of Case Studies Designed to Determine the Influence of Multiple Stressors on Benthic Communities in Urban California Streams Lenwood W. Hall, Jr.

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Presentation on theme: "Summary of Case Studies Designed to Determine the Influence of Multiple Stressors on Benthic Communities in Urban California Streams Lenwood W. Hall, Jr."— Presentation transcript:

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 1

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 2

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 3

4 California Study Areas

5 Pleasant Grove Cr. Kirker 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 6

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 7

8 8 Embeddedness Epifaunal Substrate/Available Cover

9 Benthic Macroinvertebrate (BMI) Sampling 9

10

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

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 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

13 MetalTEL (ug/g) As5.9 Cd0.596 Cr37.3 Cu35.7 Pb35 Hg0.174 Ni18 Zn123 Total Metals Sediment Threshold Effect Levels (TELs) 13

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

15 StreamYearMean Score all Sites Pleasant Grove Cr Kirker Cr Arcade Cr Salinas Streams Mean Total Physical Habitat Scores for Urban CA Streams for (Maximum Score = 200) 15

16 Salinas Main Canal at the 2994 m Transect 16

17 Salinas Stream Dirty Diaper 17

18 StreamYear# of Taxa Pleasant Grove Cr Kirker Cr Arcade Cr Salinas Streams Number of BMI Taxa for Urban CA Streams ( ) 18

19 TaxonTotal % Tubificidae unid. Immature 11.3 Micropsectra sp.7.5 Physa sp.7.4 Paratanytarsus sp. 6.6 Hyalella sp Taxon Total % Cyprididae17.5 Physa sp.16.9 Micropsectra sp Tubificidae unid. Imm Tubificidae w/hair 6.9 Five Most Dominant Benthic Taxa Pleasant Grove Cr.Kirker Cr.

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 Taxon Total % Tubificidae unid. Immature 12.6 Nais communis/ variabilis 11.5 Eukiefferiella9.4 Cricotopus6 Rheocricotopus sp TaxonTotal % Tubificidae unid. Immature 20.4 Nais communis/ variabilis 9.8 Pisidium8.8 Dugesia tigrina8.8 Physa6.8 Five Most Dominant Benthic Taxa Arcade Cr.Salinas Cr.

22 StreamYearTotal # TEL Exceedances Pleasant Grove Cr (Zn,Cu) (Zn,Cu) (Zn,Cu) Kirker Cr (As,Ni) (As,Ni) Arcade Cr (Ni,Cr) (Ni,Cr) (Ni,Cr) Salinas Streams200954(Ni,As) (Ni,As) (Ni,As) 2231 Total Number of Metal TEL Exceedances for Urban CA Streams ( ; two metals with highest #s )

23 StreamYear% Sites TUs > 1Range of TUs Pleasant Gr. Cr Kirker Cr Arcade Cr Salinas Streams Total Pyrethroid TUs based on Hyalella for Urban CA Streams ( )

24 Benthic MetricsSignificant 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+ Vel/depth % Collectors/Gatherers- Vel/depth % Grazers+As to TEL % Predators- Channel alteration 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

25 Benthic MetricsSignificant 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 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

26 Benthic MetricsSignificant 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+ Hg to TEL % Collectors/Gatherers- Embeddedness % Grazers+ Total Pyrethroid TUs - Riparian veg zone % Predators+ Pb to TEL 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

27 Benthic MetricsSignificant Variables % Collectors/Gatherers- Sediment Deposition % Grazers+ Sediment Deposition 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

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 28

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 29

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 30

31 31 StreamYears & # of samples HabitatMetalsPyrethroids Pleasant Gr. Cr (n = 63) 1270 Kirker Cr (n = 28) 641 Arcade Cr ( n = 33) 543 Salinas Streams (n = 39) 200 All streams (n = 163) Summary of Bioassessment Multiple Stressor Case Studies Showing Number of Significant Habitat, Metals and Pyrethroid Relationships to BMI Metrics


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