Risk assessment
Seven Cardinal Rules of Risk Communication
1. Involve stakeholders 2. Develop a communication plan 3. Listen to your audience 4. Be honest, open 5. Credibility 6. Plan for media influence 7. Speak clearly and with compassion
What are the 4 Components of Risk Assessment
1. Hazard identification 2. Dose‐response assessment 3. Exposure assessment 4. Risk characterization
What is Health Risk Assessment?
"Risk assessment is a process in which information is analyzed to determine if an environmental hazard might cause harm to exposed persons and ecosystems" -Health risk assessment is a scientific tool designed to answer whether current or future chemical exposures will pose health risk to a certain population.
dose-response assessment
- What level of exposure will lead to what level of effect? (cancer) - "Safe level", or level of exposure without adverse effect. (non‐cancer) • Usually data from animal model was used: No Observed Adverse Effect Level (NOAEL), or Lowest Observed Adverse Effect Level (LOAEL)
What are three good interventions for the source?
- eliminate source -limit emmissins - capture emmissions
What are three good interventions for the receptor
-limit the amount of contact -limit time near source -clean breathing aif
How can we Trust determination factors
1) Active listening skills • Paraphrasing • Active feedback • Control of non‐verbal cues 2) Non‐verbal communication • Provides up to 50‐75 percent of message content •Noticed intensely by audience •Interpreted negatively •Overrides verbal communication
Two classifications for toxic effects( Hazard identification data sources)
1) Carcinogenic - Exposure has potential to result in cancer - Toxicity values described by a "oral slope factor" • Carbon tetrachloride: 0.07 per mg/kg‐day • Arsenic: 1.5 per mg/kg‐day 2)Non‐carcinogenic (Systemic) - Anything else - Exposure above a threshold level could result in adverse effect - Toxicity values described by a "reference dose" (RfD) • Arsenic: 3 x 10‐4 mg/kg‐day
4. Trust determination theory(Four factors)
1) Caring and empathy - Audience needs to know that the messenger cares and understands 2)Openness and honesty - Tell them what you do know and do not know 3)Competence and expertise - Establish your qualifications 4)Dedication and commitment - Follow up and always keep promises
How can we Build trust and credibility
1) Caring and empathy - State why this issue is important to you on a personal level - Acknowledge importance of the issue for all stakeholders - Relate how the issue also affects your life and sense of community 2)Openness and honesty - Tell them what you do know and do not use hedging information that could be revealed later - Admit it if you do not know the answer to their question - Always respond as if there is no such thing as a bad or unimportant question 3)Competence and expertise - State your academic preparation and practical experience with the specific subject matter - Do not lord your expertise over stakeholders, use it to help them understand at their level 4)Dedication and commitment - Arrive early and stay late for meetings - Reveal level of resources directed toward the issue - Let them know you will stay on task until the issue is resolved - Offer follow‐up, keep the promise and stay on schedule
• _____________________utilize health risk assessment to determine which chemical exposure is______________attention. • Learning the basics of health risk assessment helps you understand and communicate health risk from environmental exposures. - Drinking water standard - Oil spill - fish advisory • These are the results of health risk assessment and management
1) Government agencies like EPA 2)significant or requires
Practical 3 concepts of risk communication
1) Perception = Reality •Needs to address hazards, probability, consequence 2)Communication = Skill • What to say; • Who to say it to; • Why to say it; • Where to say it; • When to say it; and • How to say it. 3)Goal = Trust + Credibility
Dose Response Relationships Two general Dose‐response models:
1) Threshold model: there is a dose below which no effect will occur. Used for systemic toxicity. - Based on the assumption that cell or body can recover by itself under certain dose 2) Non‐threshold: used for carcinogenic agents and assumes that an effect occurs at any dose, even if not readily observable - Assumes that every molecule of exposure adds more risk of cancer
Six goals for risk Assessment
1) To educate the public about risks, risk analysis, and risk management 2)To inform the public about specific risks and actions taken to alleviate them 3)To encourage personal risk reduction measures 4)To improve understanding of public values and concerns 5)To increase mutual trust and credibility between the authorities and the public 6) To resolve conflicts and controversies
Risk management philosophies
1)Concept of de minimis risk - the idea that some risks are so small that they are acceptable or insignificant from a societal perspective. 2)Risk ‐ Benefit Analysis - risks result from activities that are otherwise beneficial. 3)Cost ‐ Benefit Analysis - Abatement costs are compared to willingness‐ to ‐pay or estimated dollar value of those illnesses or deaths avoided by abating the risk. 4) Decision Analysis or Alternatives Analysis - best decisions are made after considering all the relevant potential consequences of a variety of options 5)The Precautionary Principle - Risks should be avoided even when risks are unlikely or uncertain
what is the process of an risk assessment
1)Data collection Collection and lab analysis of environmental samples from the site. Risk assessors identify "chemicals of potential concern." 2)Exposure Assessment Calculates ways people might be exposed to the chemicals identified and at what levels. Risk assessors calculate the "Reasonable Maximum Exposure" (RME) 3) Toxicity Determine the toxicity, or harmfulness, of each chemical of potential concern. Often rely on previous scientific studies of the cancer and non‐cancer effects of the substances 4) Risk characterization Risk assessors combine the results of the first three steps and come up with their estimate of the risks posed by the site.
__________________is the process of identifying and selecting environmental agent(s) and health effect(s) for assessment. • This process includes ____________________for particular health outcomes, based on the strength of the toxicological and epidemiological evidence for _______________. • Involves gathering and evaluating data
1)Hazard identification 2)causal inference 3)causation
Hazard identification data sources
1)Human data - Epidemiological data (observations) - Case report - Human volunteer studies 2)Animal data 3)Others - In vitro studies - Structure activity relationship • Physiologically‐based pharmacokinetic (PBPK) modeling
Now knows the risk, and?
1)If the risk is too high? 2)How safe is safe enough? - What is considered acceptable risk? 3)Risk management goal? - To reduce risk? - To balance risk and its benefits? - To reduce risk at reasonable cost? - others
Superfund cleanup process
1)Preliminary Assessment/Site Inspection: Evaluate the potential for a release of hazardous substances from a site. Provides the data needed for Hazard Ranking System(HRS) scoring. 2)Remedial Investigation/Feasibility Study Determines the nature and extent of contamination. Assesses the treatability of site contamination and evaluates the potential performance and cost of treatment technologies. 3)Remedial Design/Remedial Action Technical specifications for cleanup remedies and technologies are designed, and followed by actual construction or implementation phase of cleanup.
"___________is a process in which information is analyzed to determine if an environmental hazard might cause harm to ______________persons and ecosystems" -Health _________is a scientific tool designed to answer whether current or future _______________will pose health risk to a certain population.
1)Risk assessment 2)exposed 3)risk assessment 4)chemical exposures
Q: Why does it take so long? What are you doing about it? __________________ The public would like to see action, and to know that the problem is being fixed. • _____________: Unfortunately, there are no simple solutions for cleaning up hazardous waste sites. It is a complicated and time consuming process .... • _________ I have five other sites that I'm working on and I'm working hard on all of them.
1)Underlying Public Need 2)Proper response: 3)Poor Response:
why can I ask my questions now? _________________The public is saying they would like their concerns and questions addressed now instead of later • ________________ I know you all have a lot of questions that you want answered. Would it be alright if we proceed with the 10 minute presentation, which I believe will answer many of your questions .... • _______________Please let me finish my talk!
1)Underlying Public Need 2)Proper response: 3)Poor Response:
In Exposure Assessment, we try to find out
1)Who is Exposed? - Adult, Child, Special Populations 2)How Are They Exposed? - 3 common routes: Ingestion, Inhalation, Skin Contact 3)What is the Concentration of Chemical to Which They are Exposed? - ppm in Water or Soil 4)How Often, How Much Are They Exposed? - Days per year, Number of years - Volume of air breathed, food consumption
Risk assessment and Epidemiology • Most epidemiologic studies evaluate whether ______________ may be responsible for documented health problems in a specific group of people. • In contrast, health risk assessments are used to estimate ________________________ chemical exposures will pose health risks to a broad population. • Different objectives, but both are important
1)past chemical exposures 2)whether current or future
Six steps model for risk communication
1. Caring and empathy statement 2. Key message 3. Supporting facts 4. Organizational commitment statement 5. Future action statement 6. Restatement of key message
Risk Communication Principles • These four theories represent the communication challenges that must be appropriately addressed for communication success
1. Risk perception theory 2. Mental noise theory 3. Negative dominance theory 4. Trust determination theory
Cancer linearized multistage model
An upper‐bound estimate of risk per increment of dose that can be used to estimate risk probabilities for different exposure levels
Risk characterization
Asses the risk for the chemical to cause cancer or other illnesses in the general population
how do you determine if an environmental hazard might cause harm to the exposed population?
By:Estimating health risk ‐ the basics
Average daily doses (ADDs)
C: concentration (average) IR: ingestion or inhalation rate (average) ED: exposure duration Divided by: BW: body weight AT: average time, time period over which the dose is averaged
An example Risk assessment and Epidemiology
Chloroform ingestion • Chloroform is a by‐product of chlorinating drinking water • Exposure to chloroform and other disinfection by ‐ products may increase cancer rates in humans • What are the risks of consuming typical levels of chloroform in drinking water? - RfD: 0.01 (mg/kg/day)
Hazard Identification
Does the agent cause adverse effects?
Dose‐response assessment
Estimate how much of the chemical it would take to cause varying degrees of health effects that would lead to illness.
• EPA assesses multiple possible MCL or treatment technique alternatives in terms of costs (for example, the cost of installing new treatment equipment). • EPA also assesses benefits resulting from the various regulatory alternatives. Some of the benefits can be quantified (for example, cost of illness avoided), but some are unquantifiable (for example, cost savings associated with the removal of other contaminants, gaining economies of scale by merging with other water systems).
Example: Drinking Water Standard by EPA
Why Calculate Dose?
First: • For most chemicals, there is a threshold below which health effects are unlikely to occur - However for some cancer‐causing chemicals, a threshold is not assumed to exist Next: • Toxicity data can then be compared with dose to determine if health effect likely to occur
• Oral slope factor (OSF) - is an estimate of the increased cancer risk from oral exposure to a dose of 1 mg/kg‐day for a lifetime. The OSF can be multiplied by an estimate of lifetime exposure (in mg/kg‐day) to estimate the lifetime cancer risk. • Or called cancer potency factor (CPF) • Unit: (mg/kg/day)‐1 • With known exposure scenario, then we can estimate health risk Formula: Risk = dose × SF
For cancer effect
Lifetime average daily doses (LADDs)
For effects such as cancer, where the biological response is usually described in terms of lifetime probabilities, even though exposure does not occur over the entire lifetime, doses are often presented as lifetime average daily doses (LADDs)
Average daily doses (ADDs)
For many non‐cancer effects, risk assessments consider the period of time over which the exposure occurred, and often, if there are no excursions in exposure that would lead to acute effects, average exposures or doses over the period of exposure are sufficient for the assessment - Often express as Average daily doses (ADDs)
• Then use that NOAEL (or LOAEL) to derive dose that considered safe for human - Reference Dose - Need to apply safety factors based on quality of data used • Reference Dose (RfD) - Is an estimate of a daily exposure to the human population that is likely to be without an appreciable risk of adverse effects during a lifetime - Used by EPA. Other similar terms: Acceptable Daily Intakes (FDA), Minimal Risk Levels (US ATSDR)
For non‐cancer effect
Two EPA's Integrated Risk Information System (IRIS):
IRIS assessment includes the first two steps of the risk assessment process: 1)Hazard Identification, which identifies credible health hazards associated with exposure to a chemical, and 2)Dose‐Response Assessment, which characterizes the quantitative relationship between chemical exposure and each credible health hazard. These quantitative relationships are then used to derive toxicity values.
Ten Factors Influencing Risk Perception
People's perceptions of the magnitude of risk are influenced by factors other than numerical data. 1)Risks perceived to be voluntary are more accepted than risks perceived to be imposed. 2)Risks perceived to be under an individual's control are more accepted than risks perceived to be controlled by others. 3) Risks perceived to be have clear benefits are more accepted than risks perceived to have little or no benefit. 4) Risks perceived to be fairly distributed are more accepted than risks perceived to be unfairly distributed. 6)Risks perceived to be natural are more accepted than risks perceived to be manmade. 7)Risks perceived to be statistical are more accepted than risks perceived to be catastrophic. 8) Risks perceived to be generated by a trusted source are more accepted than risks perceived to be generated by an untrusted source. 9) Risks perceived to be familiar are more accepted than risks perceived to be exotic. 10)Risks perceived to affect adults are more accepted than risks perceived to affect children.
Hazard Identification
Review key research to identify any pothecial health problems that a chemical can cause.
what is an example of an risk assessment ?
Risk Assessment can be used to answer this type of question • Farmers applying atrazine as a pesticide to fields. They expose to approximately 0.3 mg of the compound each day while working with the chemical. Does the farmers' exposure to atrazine pose a hazard to their health? • Protocol of re‐openings of commercial and recreational fisheries after oil spill
• A science‐based approach for communicating effectively in: - High concern and low trust situations - Sensitive or controversial situations
Risk Communication
• Congress established the_________Program in 1980 to locate, investigate, and clean up the worst sites nationwide • EPA administers the Superfund program in cooperation with individual states and tribal governments
Superfund
Risk assessment and management in Superfund site cleanup
Superfund is the Federal government's program to clean up the nation's uncontrolled hazardous waste sites • Under the Superfund program, abandoned, accidentally spilled, or illegally dumped hazardous waste that pose a current or future threat to human health or the environment are cleaned up
Dose Response
The relationship between the degree of exposure (dose) and the magnitude of the effect (response).
Hazard Identification (HI)
To determine •Whether a particular agent may increase the incidence of specific adverse health outcomes, • and whether such outcomes are likely in humans
Exposure assessment
To determine the amount of duration, and pattern of exposure to the chemical
Exposure assessment
What are the types and levels of exposure?
Risk characterization
What is the estimated probability or incidence of adverse effects ? How robust is the edividence? How certain is the evaluation?
Dose‐response assessment
What is the relationship between dose and response ?
Develop Key Messages
• 5‐20 words in length • No technical words, jargon, or long words • Backed with at least two supporting facts • Restated exactly the same way
How do we calculate Dose?
• Dose is expressed as: mass of toxicant / body weight / time , mg toxicant / Kg body weight / day , (mg/kg/day) Includes: -Amount of toxicant -Weight of person -Time (exposure duration)
Superfund Sites
• EPA estimates 36,000 seriously contaminated sites in the U.S. - By 2004, 1,671 sites had been placed on the National Priority List (NPL) for cleanup with Superfund financing. • Superfund is a revolving pool designed to: - Provide immediate response to emergency situations posing imminent hazards. - Clean‐up abandoned or inactive sites.
Risk characterization example:
• Example: the attributable risk of kidney cancer in a frequent consumer of drinking water containing 90 μg/L of chloroform might be about 0.0026 mg/kg/day X 0.00011 (mg/kg/day)‐1 = 3 X 10‐8, or about 3 in 100 million. • To support risk manager on decision making - By providing scientific evidence and rationale about risk - in plain language • To provide basis for making risk management decision - Demonstrate how risk varies, to help decision maker evaluate different options
exposure assessment
• Exposure estimate is often not easy - Difficulties in measuring complex, time - varying behavior • Ideal exposure assessment would produce a full profile of each individual's exposures - In practice most exposure assessments are limited to estimating summary values, such as time ‐ averaged exposure rates • Many exposure assessments rely on default assumptions about media contact rate
Why Health Risk Assessment?
• Government agencies like EPA utilize health risk assessment to determine which chemical exposure is significant or requires attention. • Learning the basics of health risk assessment helps you understand and communicate health risk from environmental exposures. - Drinking water standard - Oil spill - fish advisory • These are the results of health risk assessment and management
Four major types of risk communication
• Information and education; • Behavioral change and protective action • Disaster warning and emergency notification • Joint problem solving and conflict resolution.
What can we do within a public meeting
• Listen and be responsive to people's feelings - know the underlying public needs
Positive association could be causality, if:
• No identifiable bias • Possibility of positive confounding has been considered • Association unlikely due to chance alone • Association is strong • Exhibit dose‐response relationship
2. Mental noise theory
• People who are upset have difficulty hearing and processing information • Mental noise can reduce ability to process communication by as much as 80 percent • Reasons for mental noise -Denial of issue ‐ Trauma from issue -Competing agenda ‐ Emotional arousal Implications of mental noise theory: • To transcend mental noise barriers, the messenger and the message must keep information simple and concise. • Implications of mental noise factors - Limited number of messages - Time limitations of communication - Repetition of message
3. Negative dominance theory
• People who are upset tend to think negatively • People place greater value on losses than on gains • Repetition of a negative reinforces and reaffirms the negative • Avoid using unnecessary negatives such as NO, NOT, CAN'T, DON'T, NEVER, NOTHING, NONE • Use positive or solution ‐ oriented messages
Risk characterization
• Risk characterization generally involves the integration of the data and analysis of the first three components of the risk assessment process (hazard identification, dose‐response assessment, and exposure assessment) to determine the likelihood that humans will experience any of the various forms of toxicity associated with a substance. • What is the estimated probability or incidence of adverse effects? • How robust is the evidence?
1. Risk perception theory
• Risk perception factors - Perception equals reality - What is perceived as real, is real in its consequences - Subjective - High emotional content • Risk communicators must make a distinction between objective risk (actual risk) and subjective risk (perceived risk) - Consider factors that influence risk perception
statutory authority
• SDWA Section 1412(b)(4)(B) specifies that each National primary drinking water regulation (NPDWR) will specify an MCL as close to the MCLG as is feasible, with two exceptions added in the 1996 amendments. - if the treatment to meet the feasible MCL would increase the risk from other contaminants or the technology would interfere with the treatment of other contaminants - benefits at the feasible level would not justify the costs
Examples of how risk assessment and management were practiced
• Seafood consumption advisory developed by FDA after Deep Water Horizon oil spill • Fish consumption advisory for area with mercury contamination • Arsenic drinking water standard set by EPA • Cleanup of superfund site
Evaluating data/study
• Strengths and weaknesses of each study must be considered: - Potential bias: selection bias, information bias • Exposure data • Case and health outcome definition - Size of study population - Statistical power of the analysis to detect adverse health effects • When the result is statistically significant, - Correlation = causality ?
Risk management
• The judgment and analysis that combine the scientific results of a risk assessment with economic, political, legal and social factor to produce a decision about environmental action - Impact of risk management decision • Jobs, new products, industries could be created, protected or threatened
Why is risk communication important?
• The public will need consistent information from a single, credible source • In an emergency, there could be widespread panic and fear. • If people don't know what is going on, they are more likely to panic and less likely to follow instructions for safety and security.
How is Risk Assessment Used?
• To set drinking water standards for public water supplies - X mg/L of certain chemical in water • Licensing and regulation of pesticides • Identification and clean‐up of hazardous waste sites • Emissions standards for hazardous air pollutants
In an emergency, the public will want to know?
• What happened? • What is the threat? • Who is affected? • How widespread is the threat? • What can be done to prevent illness or injury? • What can the government do for us?
Example: EPA Statutory authority
• When proposing an Maximum Contaminant Level (MCL), EPA must publish, and seek public comment on, the health risk reduction and cost analyses (HRRCA) of each alternative maximum contaminant level considered - Includes the quantifiable and nonquantifiable benefits from reductions in health risk
