1. Environmental Risk Analysis Chapter 6 © 2004 Thomson Learning/South-Western

2. 2 Concept of Risk Risk – the chance of something bad happening  Dealing with risk involves two tasks: Identifying the degree Responding to it  Policymaker must use a systematic assessment of risk before devising a policy response

3. 3 Concept of Risk Classifying Risk: Voluntary and Involuntary Risk  Voluntary risk – a risk that is deliberately assume at an individual level  Involuntary risk – a risk beyond one’s control and not the result of a willful decision

4. 4 Concept of Risk Defining Environmental Risk  Environmental risk – the probability that damage will occur due to exposure to an environmental hazard  Hazard – the source of the environmental damage  Exposure – the pathways between the source of the damage and the affected population or resource

5. 5 Risk Assessment in Environmental Decision Making Risk assessment – qualitative and quantitative evaluation of the risk posed to health or the ecology by an environmental hazard  Hazard identification – scientific analysis to determine whether a causal relationship exists between a pollutant and any adverse effects

6. 6 Risk Assessment in Environmental Decision Making Figure 6.1 Risk Assessment Process

7. 7 Risk Assessment in Environmental Decision Making  Methods of identifying environmental hazards Case clusters – study based on observation of abnormal patters of health patterns within some population group Animal bioassay – a study based on the comparative results of laboratory experiments on living organisms both before and after exposure to a given hazard Epidemiology – the study of the causes and distribution of disease in human populations based on characteristics such as age, gender, occupation, and economic status

8. 8 Risk Assessment in Environmental Decision Making Dose-Response Analysis – a quantitative relationship between doses of a contaminant and the corresponding reactions  Threshold – the level of exposure to a hazard up to which no response exists  Two types of extrapolations High-to-low dose extrapolation – adjusts for the high exposure levels used in laboratory or other test conditions Laboratory-to-natural extrapolation – infers how the effects observed in the laboratory would differ under conditions existing in nature

9. 9 Risk Assessment in Environmental Decision Making Figure 6.2 Hypothetical Dose-Response Relationships

10. 10 Risk Assessment in Environmental Decision Making Exposure Analysis – characterizes the sources of an environmental hazard, concentration levels at that point, pathways, and any sensitivities  Risk Characterization – description of risk based upon an assessment of a hazard and exposure to that hazard Quantitatively identifies magnitude of the risk and a way to compare one risk to another Qualitatively gives context to the numerical risk value

11. 11 Risk Management in Environmental Decision Making: Responding to Risk Risk Management – the decision-making process of evaluating and choosing from alternative responses to environmental risk  Two major tasks: Determining what level of risk is “acceptable” to society Evaluating and selecting the “best” policy instrument to achieve that risk level

12. 12 Risk Management in Environmental Decision Making: Responding to Risk Tasks of Risk Management  Determining Acceptable Risk “Acceptable” risk – the amount of risk determined to be tolerable for society De minimis risk – a negligible level of risk such that reducing it further would not justify the costs of doing so  Evaluating and Selecting a Policy Instrument

13. 13 Risk Management in Environmental Decision Making: Responding to Risk Risk Management Strategies  Considerations in selection of risk management strategy: The level of risk established The benefits that accrue to society from adopting the policy The associated costs of implementing the policy  Prevalent risk management strategies: Comparative risk analysis Risk-benefit analysis Benefit-cost analysis

14. 14 Risk Management in Environmental Decision Making: Responding to Risk  Comparative risk analysis – an evaluation of relative risk  Risk-benefit analysis – an assessment of risks of a hazard along with the benefits to society of not regulating that hazard  Benefit-cost analysis – a strategy that compares the MSB of a risk reduction policy to the associated MSC