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. KillenUniversity of Maryland

Wye Research and Education CenterQueenstown, Maryland

And Raymond W. Alden III

Northern Illinois University 1

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

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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

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California Study Areas

Pleasant Grove Cr. Kirker Cr.

Arcade Cr. Salinas Streams

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

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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

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Embeddedness optimal condition

Embeddedness poor condition 8

Epifaunal substrate & available cover optimal condition

Epifaunal substrate & available cover poor condition

Epifaunal substrate & available cover optimal condition

Epifaunal substrate & available cover poor condition

Embeddedness Epifaunal Substrate/Available Cover

Benthic Macroinvertebrate (BMI) Sampling

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Processing of BMI Data

Collection of

BMIs

ThreeReplicates

of 300IndividualsIdentified

by Site

Identificationto LowestTaxonomic

Level(CDFG)

BMI MetricsDevelopedfor Sites(i.e. taxarichness,

% tolerant taxa)

Methods - Continued

• The following pyrethroids were measured :Bifenthrin Cypermethrin Cyfluthrin Deltamethrin Esfenvalerate Fenpropathrin Lambda – cyhalothrin Permethrin

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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)

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Metal TEL (ug/g)

As 5.9

Cd 0.596

Cr 37.3

Cu 35.7

Pb 35

Hg 0.174

Ni 18

Zn 123

Total Metals Sediment Threshold Effect Levels (TELs)

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Methods - Continued

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

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Stream Year Mean Score all SitesPleasant Grove Cr. 2006 89

2007 982008 91

Kirker Cr. 2006 852007 66

Arcade Cr. 2009 1072010 1052011 106

Salinas Streams 2009 462010 542011 56

Mean Total Physical Habitat Scores for Urban CA Streams for 2006-2011

(Maximum Score = 200)

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Salinas Main Canal at the 2994 m Transect

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Salinas Stream Dirty Diaper

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Stream Year # of Taxa

Pleasant Grove Cr. 2006 1422007 1452008 153

Kirker Cr. 2006 1102007 114

Arcade Cr. 2009 1012010 922011 110

Salinas Streams 2009 762010 682011 71

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

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Taxon Total %

Tubificidae unid.Immature

11.3

Micropsectra sp. 7.5

Physa sp. 7.4

Paratanytarsus sp.

6.6

Hyalella sp. 5.9 19

Taxon Total %

Cyprididae 17.5

Physa sp. 16.9

Micropsectra sp.

10.7

Tubificidae unid. Imm.

10.5

Tubificidae w/hair

6.9

Five Most Dominant Benthic Taxa Pleasant Grove

Cr. Kirker Cr.

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%

Taxon Total %

Tubificidae unid.

Immature

12.6

Nais communis/

variabilis

11.5

Eukiefferiella 9.4

Cricotopus 6

Rheocricotopus sp.

5.6 21

Taxon Total %

Tubificidae unid.

Immature

20.4

Nais communis/

variabilis

9.8

Pisidium 8.8

Dugesia tigrina 8.8

Physa 6.8

Five Most Dominant Benthic Taxa

Arcade Cr. Salinas Cr.

Stream Year Total # TEL Exceedances

Pleasant Grove Cr. 2006 20 (Zn,Cu)2007 16 (Zn,Cu)2008 23(Zn,Cu)

Kirker Cr. 2006 36(As,Ni)2007 34(As,Ni)

Arcade Cr. 2009 22(Ni,Cr)2010 32(Ni,Cr)2011 20(Ni,Cr)

Salinas Streams 2009 54(Ni,As)2010 40(Ni,As)2011 31(Ni,As)

2231

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

Stream Year % Sites TUs > 1 Range of TUs

Pleasant Gr. Cr. 2006 43 0.08 - 15.3

2007 48 0.07 - 24.32008 62 0.16 - 6.1

Kirker Cr. 2006 36 0.04 - 2.72007 57 0.05 - 5.5

Arcade Cr. 2009 18 0.01 - 3.12010 45 0.28 - 6.62011 55 0.21 - 14.5

Salinas Streams 2009 85 0.40 - 61.92010 100 1.9 - 10.92011 100 4.0 - 28.32331

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

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 + 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 2008.

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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

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.

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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 + 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 2011.

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Benthic Metrics Significant 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 2011.

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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

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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

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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

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Stream Years & # of samples

Habitat Metals Pyrethroids

Pleasant Gr. Cr.

2006-2008(n = 63)

12 7 0

Kirker Cr. 2006-2007(n = 28)

6 4 1

Arcade Cr. 2009-2011( n = 33)

5 4 3

Salinas Streams

2009-2011(n = 39)

2 0 0

All streams 2006-2011(n = 163)

25 15 4

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