Aquatic Herbicides & Amphibians Applying Phenology to Toxicity Testing

43 Pages·2016·3.53 MB·English

Assessing the Hazards/Risks
Herbicides Pose to Fish and Wildlife
Christian Grue
School of Aquatic & Fishery Sciences
University of Washington
Amy Yahnke
Shorelands and Environmental Assistance Program
WA Department of Ecology
CMER, 25 October, Olympia, WA
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
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
Personal Context
Urban Stream Pesticide Cocktail
Maximum Concentrations (ppb)
(Voss 1999) (Frans 2004) LC50
2,4-D 1.00 0.69 >100,000
s
Dicamba --- 0.38 28,000
e
d Dichlobenil 1.20 0.31 6,260
i MCPA 0.40 0.38 >10,000
c
i MCPP 0.75 0.52 124,800
b
Prometon 0.27 0.19 20,000
r
e
Atrazine 0.02 --- 24,000
H
Simazine 5.00 0.42 >100,000
Triclopyr 1.30 0.74 >100,000
Carbaryl 0.05 0.06 1,950
Diazinon 0.45 0.58 90
Pentachlorophenol 0.20 0.12 115
4-nitrophenol --- 0.46 3,800
Concentrations exceed those associated with agriculture
“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
Legacy of Agent Orange
Active Ingredients vs End Products
2 billion lbs AI annually
Adjuvants
+
and
Carriers
4.1 billion lbs
“inert” ingredients annually
Active Ingredients — Formulations — Tank Mixes
A Percent of Insecticide Products by Number of AIs B Percent of Herbicide Products by Number of AIs
100 100
90 90
80 Insecticides 80 Herbicides
s s
tc 70 tc 70
u u
d 80% single AI d 65% single AI
o 60 o 60
rP rP
f o 50 f o 50
t en 40 t en 40
c c
re 30 re 30
P P
20 20
10 10
0 0
1 2 3 4 1 2 3 4
Number of Active Ingredients Number of Active Ingredients
C Number of Label-Recommended Tank Mix Combinations D Percentage of Label-Recommended Tank Mix
(Binary or Greater) Combinations with Three or More Active Ingredients
30 60
tceed 25 Herbicides t ceed 50 Herbicides
p p
l Issen 20 85% 2+ TM l Issen 40 >50% TM
b b
l aLa 15 combos l aLa 30 3+ AI
toT toT
f o 10 f o 20
t n t n
e e
rce 5 rce 10
P P
0 0
0 1 to 5 6 to 10 11 to 15 16 to 20 21 to 25 26 to 30 > 30 3 4 5
Number of Tank Mix Combinations Number of Active Ingredients
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 vulnerable
o Life history
• Example: Toxicity of aquatic herbicides to
amphibians