Transcript Slide 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
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.
Arcade Cr.
Kirker 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)
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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
Epifaunal Substrate/Available Cover
Embeddedness optimal condition
Epifaunal substrate & available cover optimal condition
Embeddedness poor condition
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Epifaunal substrate & available cover poor condition
Benthic Macroinvertebrate (BMI)
Sampling
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Processing of BMI Data
Collection
of
BMIs
Three
Replicates
of 300
Individuals
Identified
by Site
Identification
to Lowest
Taxonomic
Level
(CDFG)
BMI Metrics
Developed
for Sites
(i.e. taxa
richness,
% 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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Total Metals Sediment Threshold Effect Levels (TELs)
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
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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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Mean Total Physical Habitat Scores for
Urban CA Streams for 2006-2011
(Maximum Score = 200)
Stream
Pleasant Grove Cr.
Year
2006
Mean Score all Sites
89
Kirker Cr.
2007
2008
2006
98
91
85
2007
2009
2010
2011
66
107
105
106
2009
46
2010
2011
54
56
Arcade Cr.
Salinas Streams
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Salinas Main Canal at the 2994 m Transect
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Salinas Stream Dirty Diaper
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Number of BMI Taxa for Urban CA
Streams (2006-2011)
Stream
Year
# of Taxa
Pleasant Grove Cr.
2006
2007
2008
2006
2007
2009
2010
2011
2009
2010
2011
142
145
153
110
114
101
92
110
76
68
71
Kirker Cr.
Arcade Cr.
Salinas Streams
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Five Most Dominant Benthic Taxa
Pleasant Grove Cr.
Taxon
Total %
Tubificidae unid.
Immature
11.3
Kirker Cr.
Taxon
Total %
Cyprididae
17.5
Physa sp.
16.9
Micropsectra
sp.
10.7
10.5
6.9
Micropsectra sp.
7.5
Physa sp.
7.4
Paratanytarsus
sp.
6.6
Tubificidae
unid. Imm.
Hyalella sp.
5.9
Tubificidae
w/hair
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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%
Five Most Dominant Benthic Taxa
Arcade Cr.
Salinas Cr.
Taxon
Total %
Taxon
Total %
Tubificidae
unid.
Immature
Nais
communis/
variabilis
Eukiefferiella
12.6
Tubificidae
unid.
Immature
20.4
11.5
Nais
communis/
variabilis
9.8
9.4
Pisidium
8.8
Cricotopus
6
Dugesia tigrina
8.8
Rheocricotopus
sp.
5.6
Physa
6.8
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Total Number of Metal TEL Exceedances for Urban
CA Streams (2006-2011; two metals with highest #s)
Stream
Year
Pleasant Grove Cr.
2006
2007
2008
2006
2007
2009
2010
2011
2009
2010
2011
Kirker Cr.
Arcade Cr.
Salinas Streams
Total # TEL
Exceedances
20 (Zn,Cu)
16 (Zn,Cu)
23(Zn,Cu)
36(As,Ni)
34(As,Ni)
22(Ni,Cr)
32(Ni,Cr)
20(Ni,Cr)
54(Ni,As)
40(Ni,As)
31(Ni,As)
2231
Total Pyrethroid TUs based on Hyalella for Urban CA
Streams (2006-2011)
Stream
Year
% Sites TUs > 1
Range of TUs
Pleasant Gr. Cr.
2006
43
0.08 - 15.3
2007
2008
48
62
0.07 - 24.3
0.16 - 6.1
2006
2007
2009
36
57
18
0.04 - 2.7
0.05 - 5.5
0.01 - 3.1
2010
2011
45
55
0.28 - 6.6
0.21 - 14.5
2009
2010
85
100
0.40 - 61.9
1.9 - 10.9
2011
100
2331
4.0 - 28.3
Kirker Cr.
Arcade Cr.
Salinas Streams
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
+ Vel/depth
% Collectors/Gatherers
- Vel/depth
% Grazers
+As to TEL
% Predators
- Channel alteration
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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 25
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
+ Hg to TEL
% Collectors/Gatherers
- Embeddedness
% Grazers
+ Total Pyrethroid TUs
- Riparian veg zone
% Predators
+ Pb to TEL
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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
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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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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.
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
31