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Assessing the Hazards/Risks
Herbicides Pose to Fish and Wildlife
Christian GrueSchool of Aquatic & Fishery Sciences
University of Washington
Amy YahnkeShorelands and Environmental Assistance Program
WA Department of Ecology
CMER, 25 October, Olympia, WA
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Presentation Outline• Considerations in assessing hazards/risks:
o Importance of context in extrapolating laboratory
toxicity data to the field
• Example of integrating ecological and
operational contexts into toxicity testing
o Assessing the hazards aquatic herbicides pose to
amphibians
• Final thoughts
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Why Is Context Important?
Key to Hazard and Risk Assessment
• Environmental exposure
• Environmental, ecological, operational contexts
• Extrapolation of laboratory toxicity data to the
field
• Improving design of laboratory toxicity tests
Hazard = Toxicity + Environmental Exposure
Risk = Probability of hazard being realized
These contexts are also critical to evaluating indirect effects
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(Voss 1999) (Frans 2004) LC50
2,4-D 1.00 0.69 >100,000Dicamba --- 0.38 28,000Dichlobenil 1.20 0.31 6,260 MCPA 0.40 0.38 >10,000 MCPP 0.75 0.52 124,800Prometon 0.27 0.19 20,000Atrazine 0.02 --- 24,000Simazine 5.00 0.42 >100,000Triclopyr 1.30 0.74 >100,000Carbaryl 0.05 0.06 1,950 Diazinon 0.45 0.58 90Pentachlorophenol 0.20 0.12 1154-nitrophenol --- 0.46 3,800
Urban Stream Pesticide Cocktail
Maximum Concentrations (ppb)
Herb
icid
es
Concentrations exceed those associated with agriculture
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“Thruthiness”
“Safety of
Forest
Herbicides”
“It used to be, everyone was entitled to their own opinion, but not their own
facts. But that’s not the case anymore.
Facts matter not at all. Perception is everything. Its certainty.”Stephen Colbert, 26 January 2006
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Legacy of Agent Orange
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Active Ingredients vs End Products
+Adjuvants
and
Carriers
2 billion lbs AI annually
4.1 billion lbs
“inert” ingredients annually
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Percent of Insecticide Products by Number of AIs
0
10
20
30
40
50
60
70
80
90
100
1 2 3 4
Number of Active Ingredients
Perc
en
t o
f P
rodu
cts
Percent of Herbicide Products by Number of AIs
0
10
20
30
40
50
60
70
80
90
100
1 2 3 4
Number of Active Ingredients
Perc
en
t o
f P
rodu
cts
Number of Label-Recommended Tank Mix Combinations
(Binary or Greater)
0
5
10
15
20
25
30
0 1 to 5 6 to 10 11 to 15 16 to 20 21 to 25 26 to 30 > 30
Number of Tank Mix Combinations
Pe
rce
nt o
f To
tal L
ab
els
In
sp
ecte
d
0
10
20
30
40
50
60
3 4 5
Pe
rcen
t of Tota
l L
ab
els
Insp
ecte
d
Number of Active Ingredients
Percentage of Label-Recommended Tank Mix
Combinations with Three or More Active Ingredients DC
BA
Active Ingredients — Formulations — Tank Mixes
Insecticides
80% single AI
Herbicides
65% single AI
Herbicides
85% 2+ TM
combos
Herbicides
>50% TM
3+ AI
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Which Context is Key?
Key to Hazard/Risk Assessment is:
• Environmental exposure
o Operational practices
• What, where, when?
o Species and life stages present
• Which are most vulnerableo Life history
• Example: Toxicity of aquatic herbicides to
amphibians
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Overview• Motivation for this work
o What’s the problem?
• Pieces of work
1. Amphibian phenology and habitat use
2. Effects of triclopyr on metamorphic northern red-legged
frogs (Rana aurora)
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What’s the problem?
Frogs Tadpoles(40 CFR § 138)
Amphibian data are not required in herbicide toxicity testing
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What’s the problem?
Existing amphibian data are not relevant to PNW species
≠
Sparling et al. 2010
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What’s the problem?
Existing amphibian data are not relevant to PNW
life stages
January/February
March/April
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Different sensitivities to pesticides exist
<(Bridges 2000)
<(Harris 2000)
What’s the problem?
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What’s the problem?
No one studies aquatic formulations
≠
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What’s the problem?
We don’t have a complete picture of native amphibian
ecology
www.frog-life-cycle.com/
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What’s the problem?
We know when and where eggs are laid
Joshua Wallace, FieldHerpForum
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What’s the problem?
But when and where do they pop those legs out?
?
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What’s the problem?
Who is at risk of exposure to aquatic weed management?
www.frog-life-cycle.com/
?
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What to do about the problem?
Two Aquatic Weeds Management Fund Grants - Dept. of Ecology
Not a frog.
Not the right frog.
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Pieces of Work1. Amphibian phenology and habitat use
2. Effects of triclopyr on metamorphic northern
red-legged frogs
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Phenology & Habitat
0
10
20
30
40
50
# y
ou
ng
-of-
yea
r ob
served
Northern Red-legged FrogOregon Spotted Frog
Young-of-year Oregon spotted frogs are present in late
summer
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Northern red-legged frog metamorphs are present in late
summer
0
10
20
30
6/2
9/2
010
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/20
10
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/20
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/20
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/20
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010
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010
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/20
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/20
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/20
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/20
10
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010
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010
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/20
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/20
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/20
10
9/7
/20
10
9/9
/20
10
# m
etam
orp
hs
ob
served
Northern Red-legged Frog
Oregon Spotted Frog
Phenology & Habitat
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Triclopyr & Northern Red-legged Frogs
ecologyadventure2.edublogs.org/plant/purple-loosestrife/
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Tank mix- labeled rates in 2cm water depth:
+
\ 47.1 ppm
41.3 ppm
+
12.9 ppm
Triclopyr Tank Mix Methods
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\Control (clean water)
X 15
96 h static renewal
47.1 ppm
Triclopyr Tank Mix Methods
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Control (clean water)
X 15
60-d growout
\Tank mix
(clean water)
Triclopyr Tank Mix Methods
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Endpoints:
1. 2. 3.
4. 5. 6.
www.mintees.com/tees/3953-liver-going-the-extra-bile/
Triclopyr Tank Mix Methods
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• No treatment-related mortalities• No gross anomalies in gonad structure• No treatment-related anomalies in over-all health
Triclopyr Tank Mix Results
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Evidence of stress during exposure.
Behavior
# Observations Legs sprawled (n)
Moving (n)
Control 2 (2) 7 (6)
Tankmix 22 (12) 12 (8)
K-S p 0.013 1.000
Triclopyr Tank Mix Results
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0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
CONTROL TANK MIX
Pro
po
rtio
n o
f ti
me
on
sq
uar
es
Black
No evidence of color preference
Behavior
P > 0.75Xc
2 = 0.10
Triclopyr Tank Mix Results
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10
11
12
13
control tank mix
Day
s
t-test P = 0.031
Triclopyr Tank Mix Results
Time to complete metamorphosis
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0
0.5
1
1.5
2
2.5
3
0 4
Bo
dy
Co
nd
itio
n
Days
control
Tank mix
t-test on Δ P = 0.113
Triclopyr Tank Mix Results
More evidence of stress during exposure?
Body condition at 96-h
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Eventually the controls caught up
Body condition over time
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 4 12 42 66
Bo
dy
Co
nd
itio
n
Days
Control
Tank mix
Metamorphosis complete
30-d post-metamorphosis
Triclopyr Tank Mix Results
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Everyone started eating at the same time
First time
eating crickets
after metamorphosis
Triclopyr Tank Mix Results
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0
20
40
60
80
100
120
140
160
0 1 2 3 4 5 6 7 8 9 1011121314151617181920212223242526272829303132333435363738394041424344454647484950515253
Mea
n c
um
ula
tiv
e cr
ick
ets
eate
n
Days since metamorphosis
CONTROL
TANK MIX
Feeding behavior LMM day 53, P = 0.199
Triclopyr Tank Mix Results
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0
0.01
0.02
0.03
0.04
0.05
Liv
er C
on
dit
ion
Control Tank mix
t-test P = 0.942
Triclopyr Tank Mix Results
No difference in liver condition
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Triclopyr Tank Mix Results
No difference in liver histology
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• Minimal effects observed
• Stress during exposure – what is real exposure in field?
• Data recording minimal observed effects from
herbicide tank mixes are important in conservation
work
o Provides support for managers working with protected or
invasive species
o Informs policy and fills data gaps
Triclopyr Tank Mix Conclusions
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Final Thoughts• Presence of pesticides in surface waters does not
necessarily translate to hazard
• Incorporating ecological processes into toxicity
testing can improve our ability to inform policy and
the public
• “Effects” sell! … but “no effects” can be just as
important in supporting habitat management
decision-making
• There are risks associated with “no action”
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Final Thoughts• We, as users of herbicides, must do our part to
minimize non-target effects
• IPM = Adaptive Management
o Uncertainty drives the process, but does not paralyze it
• Unfortunately, AM is the exception and not the rule
Associated journal papers are available in the Archives of Environmental
Contamination and Toxicology (King) and Environmental Toxicology and
Chemistry (King, Yahnke)