Risk assessment

Question 1

Risk Assessment

Answer 1

A process for estimating the likelihood of
adverse (ecological, human health) impact
resulting from anthropogenic stress

Question 2

Prospective vs Retrospective

Answer 2

-To predict future effects
-To evaluate describe and diagnose past impact

Question 3

Qualitative vs quantitative

Answer 3

 Qualitative descriptions
 Quantitative descriptions assessing
frequency and magnitude of effect and
associated probabilities

Question 4

Ecological RA

Answer 4

Individuals, populations,
communities, ecosystems. Focus on the population, some exceptions.

Question 5

Human Health RA

Answer 5

Individual humans,
with some focus on susceptible sub-
populations

Question 6

RA: Problem formulation (PF)

Answer 6

conceptualization of risk
problem and
development of
assessment plan

Question 7

RA: Analysis (A)

Answer 7

estimate of
exposure and exposure-
response profiles

Question 8

Risk characterization (RC)

Answer 8

summary of the
estimate of likelihood of
adverse effects

Question 9

PF: Assessment endpoints

Answer 9

environmental conditions or processes with
ecological, economic, and/or societal value
 may not be measurable directly
 examples: habitat suitability, vitality of salmon
populations, “fishable-swimable” designated use

Question 10

PF: Measures of effect

Answer 10

 quantifiable indicators of environmental conditions
or processes
 examples: abundance and distribution of nesting
sites, age structure of salmon, fecal bacteria
concentrations in surface waters

Question 11

Conceptual Model (PF)

Answer 11

Helps in PF
Working hypotheses relating exposure to effects (primary and secondary)
 Identifies critical data collection and analysis activities
 Defines remainder of the assessment

Question 12

A: Exposure Profile

Answer 12

product of characterization of exposure
 summarizes spatial and temporal patterns
of co-occurrence of stressor with ecological and human receptors

Question 13

A: Stressor-Response Profile

Answer 13

 product of characterization of effects
 summarizes relationships between exposure and effect

Question 14

Estimating Exposure

Answer 14

Sources, - inventories, direct measures, models
Transport, transformation, and fate -models, direct measurers.
Concentration at site of toxic action

Question 15

Exposure versus Dose

Answer 15

External exposure used as surrogate for dose at site of toxic action
 Chemical residues (which account for bioaccumulation) sometimes provide more direct and integrated indicators of dose at site of toxic action

Question 16

A: Stressor-Response Profile

Answer 16

Developed by empirical
or mechanistic modeling
 Permits estimation of
incremental effects
 Supports dynamic
simulation of risk

Question 17

A: Risk Quantification Methods

Answer 17

Qualitative
 quotient method
 weight-of-evidence

Quantitative
 joint probability
 simulation modeling

Question 18

Risk Characterization

Answer 18

Includes summary of:
 Weight of evidence – modeled and measured
exposure; multiple measures of effect; media-
specific risk
 Uncertainties - variability, measurement
precision and accuracy
 Assumptions
 Data gaps – extrapolations

Question 19

Risk Assessment Paradigm

Answer 19

Estimate of
Environmental
Exposure
Concentration
+
Estimate of
Acceptable
Environmental
Concentration
=
Risk Characterization