1. Chapter 15.3 Risk Assessment 2002 WHO report: “Focusing on risks to health is the key to preventing disease and injury.” risk assessment—process of evaluating the risks associated with a particular hazard before taking some action in a situation in which the hazard is present risk can be expressed as days of lost life expectancy may also be expressed as probability of dying from a specific hazard

2. environmental risk assessment by the EPA risk assessment began at the EPA in the mid-1970s as a way of addressing the cancer risks associated with pesticides and toxic chemicals currently has four steps: hazard assessment dose-response assessment exposure assessment risk characterization

3. hazard assessment process of examining evidence linking a potential hazard to its harmful effects for automobile accidents, link is clear other cases are not as clear; may be time delay between first exposure and final outcome Ex. establishing link between exposure to chemical and cancer

4. animal testing test involving several hundred animals (usually mice) takes about 3 years and costs more than $250,000 if a significant number develop tumors after being fed substance, then the substance is either a possible or probable carcinogen three objections to animal testing rodents and humans may have very different responses to a chemical doses used on animals are often much higher than those humans would be exposed to testing on animals is unethical

5. dose response assessment when animal tests or human studies show a link between exposure to a chemical and an ill effect, the next step is to analyze the relationship between the concentrations of chemicals in the test (dose) and both the incidence and severity of the response unless there is reason to assume otherwise, a linear response is used to determine an acceptable level of exposure

6. exposure assessment involves identifying human groups already exposed to the chemical, learning how their exposure came about, and calculating the doses and length of time of their exposure

7. risk characterization pulls together all the information gathered in the first three steps to determine the risk and any uncertainties risk is commonly expressed as probability of a fatal outcome due to the hazard Clean Air Act directs the EPA to regulate chemicals that have a cancer risk of greater than one in a million for the people who are subject to the highest doses FDA applies same standard to regulate chemicals in food, drugs, and cosmetics final estimate always recognizes degree of uncertainty

8. public health risk assessment DALY risk data must be assessed with a common measure if risk data is to be compared WHO reports use DALY—disability adjusted life year one DALY represents the loss of one healthy year of a person’s life assesses burden of disease in terms of life lost due to premature mortality and timed lived with disability

9. risk management involves: (1) a thorough review of the information available pertaining to the hazard in question and the risk characterization of the hazard (2) a decision as to whether the weight of the evidence justifies a regulatory action a regulatory decision will usually depend on: 1. cost-benefit analysis 2. risk-benefit analysis 3. public preference

10. risk perception intuitive judgments about risks Ex. protests against nuclear power plants people’s perceptions are not always consistent with results coming from scientific analysis of risk perceptions can be based on lack of familiarity with technology public impression of hazards media coverage

11. as always… …the precautionary principle

12. LD50 the amount or dose of a chemical (toxic substance) that kills half the test population (test organisms/specimens)

13. threshold level of toxicity The dose (level) below which no toxic (lethal) effects are observed and/or above which the toxic (lethal) effects are apparent.