What's Risk Assessment?

Risk Assessment / Risk Communication
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Frumkin H [Ed.] (2010) Environmental Health: From Global to Local, 2nd Ed. Chapter
29 "Risk Assessment" (by Scott Bartell) pp.1037-62, Chapter 31 "Risk
Communication" (by Vincent T. Covello) pp. 1099-1140.
Risk Assessment●
Hazard identification + dose-response assessment + exposure assessment + risk
characterization●
Dose-response <- animal experiment + statistical model●
De minimis risk: risk management concept●
Interdisciplinary new techniques: CVM, CRA, etc.
Risk Communication●
Two-way exchange of information about environmental, health, and safety threats●Core public health function to inform the public, achieve behavioral change,
provide warnings of disasters and emergencies●
Applicable to emergency situation●
Practiced by governmental agencies, NGO, private sector●
Based on an understanding of the determinants of risk perception
Reference web pages and books for risk communication●
http://fshn.ifas.ufl.edu/seafood/sst/27thAnn/SP05.pdf●
http://www.ecdc.europa.eu/en/publications/publications/risk-communicationliterary-review-jan-2013.pdf●
岩田健太郎 (2014) 『「感染症パニック」を防げ！ リスク・コミュニケーション入門』
光文社新書， ISBX978-4-334-03828-1●●

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Process●●●

Example: chloroform (as a by-product of water chlorination tosterilize) ingestion at average concentration of 1 to 90 µg/L in
USA drinking water systems. Water chlorination is very
effective to eliminate cholera and other waterborne diseases.
Exposure to chloroform may increase cancer.
In 1970s, the impossibility of "zero-risk" has been realized.
-> determination of acceptable limits for concentrations ofpollutants in air, water, soil, biota and in emissions.
In 1983, NRC report "Risk Assessment in the Federal
Government" (a.k.a. Red Book) divided it into 4 elements●
hazard identification●
dose-response assessment●
exposure assessment●
risk characterization
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The process of identifying and evaluating adverse events that
could occur in defined scenarios●
Scenarios must be defined, including many events●
Major assessors: (1) What can happen? (2) How likely is it tohappen? (3) What are the consequences if it does happen?
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In environmental health settings: risk assessors focus on"health impacts" <- exposure to a particular agent / working in,living in, or visiting a particular environment– For instance, assessment of drinking water with chemicalor microbial contaminants, or of eating fish contaminatedwith mercury or PCBs●
Environmental health risk assessment: quantitative framework
for evaluating and combining evidence from toxicology,
epidemiology and other disciplines -> decision making
Risk assessment does not generate new evidence, but synthesize
existing scientific information to address specific regulatory or
policy issues.

Hazard identification●●

Identifying and selecting environmental agents and health effects forassessment●
causal inference for particular health outcomes<- strength of toxicological/epidemiological evidences●
single agent / single health effect -> straightforward●
broad inquiry for multiple agents / multiple health effects ->selection of key agents / most important health effects– In 1970s, widespread concern with the potential contribution ofenvironmental pollution rising cancer rates -> assessments
focused on cancer– High level chloroform in drinking water can cause cancer in lab.
animals (EPA, 2001). The slight increases of bladder, rectal,colon cancer were observed in humans who drink chlorinateddrinking water <- many epidemiological studies, but unclear
whether it was caused by chloroform or not.
– fish with low level chemical contaminants is another example
IARC (International Agency for Research on Cancer) published morethan 90 monographs and classified agents into several weight ofevidence categories (Group 1, Group 2A, Group 2B, Group 3, Group 4)
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Example of Dose-Response
Assessment

Dose-Response Assessment●●

Attempts to describe the quantitative relationshipbetween exposure and disease●
Direct evidence -> mathematical dose-response modelis unnecessary: Rare case●
Usually no direct evidence -> relying on mathematicalmodels●Mathematical models may also be used to adjust effectestimates for differences in species, gender, race, ...
(confounders)
The most famous dose-response model for cancer"Linearized Multistage Model": Assuming every moleculeof exposure adds more risk to cancer●"Threshold model" assumes that nobody exposed at alevel below a critical threshold dose will develop
cancer as the result of exposure

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Exposure Assessment●●●

Estimation/measurement of the following aspects of human
exposures to the agent of concern (NRC, 1994)●
magnitude●
duration●timingOften quite difficult, especially in the case of time-varying
behavior such as the frequency and amounts of water
consumption, origins of soil and dust unintentionally to ingest
or to inhale
Full profile of each individual's exposures over time is ideal,
but usually unavailable. Usually using time-averaged exposure
rates, especially media contact rates●
Chloroform in drinking water (> 90µg/L): drinking water
ingestion + skin absorption and inhalation in bathing, ...
●EPA assume that an adult drinks 2L water: if the one's bodyweight is 70kg, the exposure is 2 x 90 / 70 = 2.6 µg/kg/day.
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Carcinogenic effects of chloroform on male rats●
Haas1994 <- data.frame(dose = c(0, 19, 38, 81, 160),
tested = c(301, 313, 148, 48, 50),kidneytumor = c(4, 4, 4, 3, 7),
proportion = c(0.013, 0.013, 0.027, 0.063, 0.140))●
plot(proportion ~ dose, data=Haas1994, type="b")●fit <- glm(cbind(kidneytumor, testedkidneytumor)~dose, data=Haas1994, family=binomial)●# Logistic regression●
summary(fit)●exp(coef(fit)[2])
Then we can get the estimate of odds ratio as 1.016,
whereas the Haas (1994) estimated 0.00011 (/mg/kg/day)cancer risk added for lifetime based on 2 stage model.

Risk Characterization: The Final Step
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Combining the information from the other 3 steps toestimate the level of response for the identified healtheffects at the specific level of exposure
Terms to estimate●
relative risk: P(d)/P(0)●additional risk (absolute risk): P(d)-P(0)●attributable risk (excess risk): (P(d)-P(0))/(1-P(0))
Chloroform: 0.0026 mg/kg/day x 0.00011 (/mg/kg/day) = 3
in 100 million.
The Red Book emphasize the uncertainties with this step.
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Qualitative uncertainties: carcinogenicity of low
exposure●
Quantitative uncertainties: the shape of dose-responsemodel. Including the control (zero dose) data makes
the estimate interpolated, not extrapolated

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What's Risk Communication?

(cf.) Risk Management
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Chloroform in drinking water causes 3 in 100 million kidneycancer.
●38% in women and 46% in men were killed by cancer in USA●"3 in 100 million" is a drop in the bucket, so that nobody
would care such a drop
What should a risk manager do?
●"de minimis risk" concept●risk-benefit analysis●
cost-benefit analysis– contingency valuation method (CVM) or comparative risk
assessment (CRA) should also be applied●
decision analysis or alternative analysis●
paying attention to the "precautionary principle""Grey Book" (2008) ~ "Science and decisions: Advancing risk
assessment" by U.S. EPA's landmark report.

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One of the core practices for public health professionals.
Definition: "Inform, educate and empower people about
health issues" (CDC, 2008) as a special category of healthcommunication, included in 10 essential public healthservices.
Two way exchange of information about environment,
health, and safety threats (incl. hazardous waste, watercontamination, air pollution, radiation, ...).
Four major types by objectives (Covello, 2010)●
Information and education●
Behavioral change and protective action●
Disaster warning and emergency notification●
Joint problem solving and conflict resolution
Two types by situation (Sandman, 2003; 岩田 , 2014)●
Crisis communication: High-outrage, high-hazard●
Non-crisis communication: Other situation

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7 essential rules for effective risk communication(slightly modified from Covello, 2010)
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Accept and involve the receiver of information as a legitimate
partner: People have rights to participate in decisions
Plan and tailor risk communication strategies: Differential
goals, audiences, channels require different strategies
Listen to your audience: Whether people have more interests in
psychological aspects or technical aspects? Identification ofaudience's true concern is essential
Be honest, frank, and open: Trust and credibility are among themost valuable assets of a risk communicator
Coordinate and collaborative with other credible sources: Withreferrals to credible, neutral sources of information,communications are enhanced.
Plan for media influence: The media plays a major role intransmitting information. Know how the media delivers.
Speak clearly, with compassion: Technical terms/jargon will bea barrier. Abstract/unfeeling/emotional words must be avoided.
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Outcome of Effective Risk
Communication●●●

Informed decision making
Establishing public confidence in the ability of individuals
and organization to deal with an environmental, health, orsafety risk
Provides people with timely, accurate, clear, objective,
consistent, and complete risk information
Creates an informed public:●
Involved, interested, reasonable, thoughtful, solution
oriented, cooperative and collaborative●
Appropriately concerned about the risk●
More likely to engage in appropriate behaviors

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Risk Communication Models (1)●Challenges to effective risk
communication●●

Risk Perception Model (cont'd) and Other Models

Risk perception model●
Paradox in risk perception: difference between the risk to kill or harm
people and the risk to alert them
– No correlation between the ranking of hazards by the statistics on
expected annual mortality and the ranking of the same hazards by
how upsetting they are to people.
– (eg.) Ebola virus made no death in Japan in 2014, but the people
were afraid of it due to TV/newspaper info.
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The paradox is explained by the factors affecting how risks areperceived → Important risk perception factors are:– Trust- Effects on children– Voluntariness- Effects on future generations– Controllability- Victim identity– Familiarity- Dread (~ fear)– Fairness- Media attention– Benefits- Accident history– Catastrophic potential- Reversibility– Understanding- Personal stake– Uncertainty- Ethical or moral nature– Delayed effects- Human vs natural origin
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Media selectivity / Media bias●
Newsworthiness●
Division of labor●
Generalist journalists●
Resources●
Objectivity and balance●
Career advancement●
Watchdogs●
Source dependency●
Competition●
Deadliness●Information compression
Factors to create misperception / misunderstanding●
Availability, conformity, overconfidence in one's ability to
avoid harm, confirmatory bias, uncertainty, reluctance
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Sandman (1989), Slovic (2000), Fischhoff (1995) and others revealed thatpeople often assess risk more in terms of these perceived risk factors
than in terms of actual potential for harm or hazard●
For the public, Risk = Hazard + Outrage●
Outrage often takes on strong emotional overtones, in turn, makes
people perceive exaggerated risk than actual●(eg.) Considering NIMBY controversy, an unfair risk is often perceived
as more risky. Why other prefectures denied to accept solid wastes
from Fukushima?
The mental noise model: Considering how people process information
under the serious stress. Stress causes mental noise, then information
processing is damaged.
The negative dominance model: Considering the processing of negativeand positive information in high-concern and emotionally charged
situations. Negative words often dominates.
The trust determination model: Considering importance of trust in
effective risk communications. Determinants of trusts are: (1) Listening,caring, empathy, compassion (50%), (2) Competence, expertise,knowledge (15-20%), (3) Honesty, openness, transparency (15-20%), (4)Other factors (15-20%).
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Strategies for effective risk communication
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Preparing a comprehensive risk and crisis communication plan
Message mapping: contributes to clarity on what is to becommunicated●(template example)
Stakeholder:
Question or concern:
Key Message 1
Key Message 2
Key Message 3
Supporting
Supporting
Supporting
information 1-1
information 2-1
information 3-1
Supporting
Supporting
Supporting
information 1-2
information 2-2
information 3-2...
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Crucial final step: Systematic message testing using
standardized procedures
Using and communicating high-quality information
Fostering comprehensive, balanced media reporting
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