caddis - risk-based prioritization and diagnosing the risk drivers
DESCRIPTION
CADDIS - Risk-based Prioritization and Diagnosing the Risk Drivers. Susan Cormier, Ph.D. NCEA-Cincinnati and the whole CADDIS team. Cumulative Risks. Cumulative Causes. Assessments of Cumulative Causes, CADDIS, and a Case. Given this effect, what is the probable cause?. - PowerPoint PPT PresentationTRANSCRIPT
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CADDIS - Risk-based Prioritization and Diagnosing the Risk Drivers
Susan Cormier, Ph.D. NCEA-Cincinnatiand the whole CADDIS team
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Assessments of Cumulative Causes, CADDIS,
and a Case
Cumulative Causes
Cumulative Risks
3Given this cause, what is the probable effect?
Risk Given C what will E be?– Given what we know of the mixture or the
individual components of the mixture, what are the probabilities and types of effects that may occur?
Given this effect, what is the probable cause?
Cause Given E what was C?– Given what we know of the effects, what is
the likely exposure scenario or combination of exposures that caused these effects?
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Cumulative Causes
Cumulative Risks
Different Questions Different Analyses
Different Logic
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Cumulative Risks
Cumulative Causes
Different Kinds of Assessments
Different Questions Different Analyses
Different Logic
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The Basic EA Framework
Condition Assessment
Outcome Assessment
Predictive Assessments
Causal Assessments
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The Basic EA Framework
Condition Assessment
Outcome Assessment
Predictive Assessments
Causal Assessments
Problem Detection
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The Basic EA Framework
Condition Assessment
Outcome Assessment
Predictive Assessments
Causal Assessments
Problem Resolution
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The Basic EA Framework
Condition Assessment
Outcome Assessment
Predictive Assessments
Causal Assessments
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Analysis from Effect to Cause
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The Basic EA Framework
Condition Assessment
Outcome Assessment
Predictive Assessments
Causal Assessments
Analysis from Cause to Effect
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The Basic EA Framework
Condition Assessment
Outcome Assessment
Predictive Assessments
Causal Assessments
Analysis from Cause to Effect
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Problem Resolution
Problem Detection
Analysis from Effect to Cause
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Condition Assessment
Problem Detection
Causal Assessment
Environmental Epidemiology
Predictive Assessment
Risk
Outcome Assessment
Environmental Management
Problem Resolution
Problem Resolution
Criteria Setting, Risk Assessment
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Condition Assessment
Biological
Problem Detection
Causal Assessment
Environmental Epidemiology
Predictive AssessmentOutcome Assessment
Environmental Management
Problem Resolution
Problem Resolution
Meet Aquatic Life Standards
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Condition Assessment
Problem Detection
Causal Assessment
Environmental Epidemiology
Predictive Assessment
Management
Risk
Outcome Assessment
Environmental Management
Problem Resolution
SourceCause
Outcome
Endangered Species
Problem Resolution
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Condition Assessment
Problem Detection
Causal Assessment
Environmental Epidemiology
Predictive Assessment
Management
Risk
Outcome Assessment
Environmental Management
Problem Resolution
Outcome
Hurricane Approaching
Problem Resolution
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CADDIS: EPA Website for Ecological Causal Assessment
Condition Assessment
Outcome Assessment
Analysis from Cause to Effect
En
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En
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Problem Resolution
Problem Detection
Analysis from Effect to Cause
Causal Assessments
Predictive Assessments
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Ecoepidemiological assessments reflect cumulative causes and effects
CADDIS is a guide to causal inference for specific cases
larvae adult
Condition Assessment
Outcome Assessment
Predictive Assessments
Causal Assessments
www.epa.gov/caddis
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Home Page
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Step-by Step Guide Introduction
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Candidate CausesAlso useful for
Risk Assessment
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Analyzing DataAlso useful for
Risk Assessment
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Conceptual Models Also useful for
Risk Assessment
Databases
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The Basic EA Framework
Condition Assessment
Outcome Assessment
Predictive Assessments
Causal Assessments
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Stream Organisms
Degraded Stream
Organisms
mayfly caddisflystonefly
blackfly
pouch snail
chironomid
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Case Study - Willimantic River, CT
#
Clean Water Act305b report to Congress
TMDLs target Cu, Pb, Zn
POTW
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Roaring Brook, Willimantic River Watershed
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Below POTW
Willimantic River
Above POTW
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Invertebrate Index Scores as % of reference site RB1
0
20
40
60
80
100
RB1 FB2 FB5 MR1 MR2 MR3 WL1 WL2 WL3 WL4 SR HR TR
Moderately impaired
Define the Biological Impairment
First appearance of downstream impairment
Compared to further upstream
Not impaired
Impaired
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Willimantic River Study Area
• Area of concern
• Upstream impairment identified
POTW
#
MR1 MR3
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The Basic EA Framework
Condition Assessment
Outcome Assessment
Predictive Assessments
Causal Assessments
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• Specific Causation– Causal: Did smoking cause my cancer– Risk: Will my smoking cause cancer
• General Causation– Causal: Does smoking cause cancer– Risk: Can smoking cause cancer
Types of Causation
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• General Causation– Does C cause E– Can C cause E
• Specific Causation– Did C cause E– Will C cause E
Types of Causation
Evidence from the Case
Evidence from
the Elsewhere
Sources of Data for Evidence
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Develop and Evaluate Evidence
• Refutation
• Diagnosis
• Weight of evidence
36Percent Fines
Pro
babi
lity
of
Obs
ervi
ng <
9 E
PT
Tax
a
0 20 40 60 80 100
0.0
0.2
0.4
0.6
0.8
1.0
Exposure Characterization
Cause/Effect Model
Logistic Regression MAIA Probability of <9 EPT for %fines
Risk of effect
Risk
Assessment
37Percent Fines
Pro
babi
lity
of
Obs
ervi
ng <
9 E
PT
Tax
a
0 20 40 60 80 100
0.0
0.2
0.4
0.6
0.8
1.0
Exposure Characterization
Cause/Effect Model
Logistic Regression MAIA Probability of <9 EPT for %finesCausal
Assessment
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Middle River
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Furnace Brook
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List of Candidate Causes
1. toxicity from metals, ammonia (NH3), or a complex mixture
2. high flows removal of organisms during
3. settled particles filling interstitial habitat
4. low dissolved oxygen
5. thermal stress 6. altered food resources favoring filter feeders
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Weight of evidence
• Types of evidence – Adapted from Hill’s Considerations
• Scoring– Source of information
• Observation• Manipulation• General Knowledge
– Quality of evidence• From the case or elsewhere• Specificity, Consistency and other qualities
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Willimantic case study Metals NH3 Flow SiltLow DO
Temp Food Episodic
Mix
Spatial/Temporal Co-Occurrence
+ - + - - - + +
Evidence of Biological Mechanism
+ + - - + + + +
Causal Pathway - + - - + + +
Stressor-Response from the Field
+ - - + +
Manipulation of Exposure + + +
Verified Predictions + + +
Stressor-Response from Other Field Studies
- - +
Stressor-Response from Laboratory
+ + - - +
Consistency of Evidence - - - - - + + + + +
Weighted Body of Evidence
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Invertebrate Index Scores as % of reference site RB1
0
20
40
60
80
100
RB1 FB2 FB5 MR1 MR2 MR3 WL1 WL2 WL3 WL4 SR HR TR
Cause: Toxic mixture
Source: Broken effluent pipe
Moderately impaired
Not impaired
Impaired
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Unknown source
Sustained exposure
Episodic exposure
Ammonia levels greater upstream
Cr Cd & CuAl, Fe, Pb,
Ni, ZnAmmonia Mixture
Cr benchmark exceeded, but form not likely hexavalent Cr
Cu & Cd benchmarks
exceeded, but unimpaired sites also exceeded
Al, Fe, Pb, Ni, Zn did not exceed toxic benchmarks
Ammonia did not exceed toxic levels
After repairing broken pipe, Al, Cd, Cr, Pb, Fe, Zn decreased &
more species observed
Death or reproductive
failure
Loss of invertebrate
species
~ ~~~
~
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Invertebrate Index Scores as % of reference site RB1
0
20
40
60
80
100
RB1 FB2 FB5 MR1 MR2 MR3 WL1 WL2 WL3 WL4 SR HR TR
Moderately impaired
Not impaired
Impaired
Cause: Heat &Altered food resources
Sources: Impoundments
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Predictive Assessment
Risk: Repairing broken effluent pipe and reducing metal release from POTW—no risk assessment, legally required remedies and no associated risks.
Expectation: reduce toxic effects, returning this segment to condition similar to those upstream. Moderate effects from stressors associated unless old mill dams were
removed.
Risk: Removing dams: risk assessments of removal options necessary because unmanaged release of sediment would bury downstream reach and may contain toxic substances
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Predictive AssessmentManagement: • Repair pipe —None, responsible parties complied. • More stringent NPDES permit at POTW—none,
responsible parties complied and monitoring of effluent continues.
• Removal of dams—Due to concerns about cost, social acceptance, and uncertainty of causes, CT DEP chose to study effects of impervious surfaces and dams on biological condition throughout the state. Small dams could provide aesthetically attractive cascades. Consultation with public would be required for optimizing benefits of selective dam removal.
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The Basic EA Framework
Condition Assessment
Outcome Assessment
Predictive Assessments
Causal Assessments
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After fixing the illicit discharge
Willimantic River WL 1
0102030405060708090
100
1999 2000 2001 2002 2003
% o
f Ref
eren
ce S
iteMiddle River MR3
0
20
40
60
80
100
1999 2000 2001 2002 2003
% o
f Ref
eren
ce S
ite
Meets Water Quality Criteria
Meets Water Quality Criteria
Willimantic River WL 1
0102030405060708090
100
1999 2000 2001 2002 2003
% o
f Ref
eren
ce S
iteMiddle River MR3
0
20
40
60
80
100
1999 2000 2001 2002 2003
% o
f Ref
eren
ce S
ite
Meets Water Quality Criteria
Meets Water Quality Criteria
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CADDIS is a guide to causal inference for specific cases
www.epa.gov/caddis
513-569-7995
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SHORT COURSE: Causal Analysis/Stressor Identification
by Susan Cormier
National Center for Environmental Assessment, USEPA, Cincinnati
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