5.1.4 What is RISK?
Risk = probability of harm X probability of exposure
Assessing Risks
Relative risk and perceptions
1. De-emphasize risk of activities we enjoy
2. Understanding "chance in 100" type assessments
3. Personal experience plays a role in perceived risk
4. Ability to control our own fate is over estimated
5. News media accounts of risk are not always "real"
6. Familiarity (or lack thereof) affects perception of risk
Accepting Risks
Reaction to emotion is more persuasive than statistics: more people
willing to accept an activity (automobile driving) that is much more dangerous than nuclear energy and other high emotion, but
low risk encounters
Establishing Public Policy
-Scientific results may not provide enough information for establishing public health risks (saccharin, aspartame)
-Standard setting needs to consider:
1.Combined effects from different sources
2.Sensitivities
3.Chronic and acute exposures
-Difficult to find line between repair mechanisms maintaining healthy status and risk of bodily damage
-Policy decisions need to consider ecological impacts (EPA)
According Relative Risks to human welfare
Relatively High-Risk Problems
-Habitat alteration and destruction
-Species extinction and loss of biological diversity
-Stratospheric ozone depletion
-Global climate change
Relatively Medium-Risk Problems
- Herbicides/pesticides
-Toxics and pollutants in surface waters
-Acid deposition
-Airborne toxics
Relatively Low-Risk Problems
-Oil spills
-Groundwater pollution
-Radionuclides
-Thermal pollution
Source: Data from Environmental Protection Agency
Summary
1) Health a state of physical, mental, social well-being, not just absence of disease
2) Most important health threats: pathogenic organisms (especially emergent and resistant microorganisms)
3) Stress, diet, and lifestyle: important health factors
4) Dose of toxic exposure can be difficult to equate with health risk
5) Distribution of materials in environment depend on may factors: physical, chemical, transport in and out of organisms
6) Forced to use estimators of actual risk; leads to many questions regarding health
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