1. RISK ASSESSMENT

2. Major Issues to be considered in designing the Study 1.- Emission Inventory What is the relative significance of the various sources. Which of the sources are more difficult to reduce 2.- Ambient concentrations What type of environmental monitoring strategy is required? 3.- Exposure of the population and ecological receptors. What are the potential exposure pathways? Which segments of the population are likely to be most exposed? 4.- Environmental and Health risks. What information is required?.

3. Dose-response functions for carcinogenic and non-carcinogenic pollutants

4. Human health Dose-response The risk of carcinogenic pollutants is estimated with a factor of potential cancer. The risk of non-carcinogenic pollutants is characterised by a reference dose. These values for non-carcinogenic endpoints are called: Oral Reference Doses (RfDs) Inhalation Reference Concentrations (RfCs) by the USEPA, ( U.S. Environmental Protection Agency ) Acceptable Daily Intakes (ADIs) by the FDA ( Food and Drug Administration) Oral and inhalation Minimal Risk Levels (MRLs) by ATSDR.(Agency for Toxic Substances and Disease Registry )

5. EXPOSURE ASSESSMENT Is the estimation of the concentration/doses to which human populations or environmental compartments are or may be exposed. Characteristics to be taken into account: Magnitude of actual and/or potential receptor exposures to environmental contaminants. Frequency and duration of these exposures Nature and size of the populations potentially at risk Pathways by which the risk group may be exposed

6. Cancerigen Risk = Dose (mg/kg d) * FP (mg/kg/d) -1 Cancerigen Risk Cancerigen Risk = 1x10 -4 (the probability of cancer risk occurring is one in a population of 10000) The maximum acceptable risk of 1.10 -6.

7. RISK ANALYSIS STEPS: 1.- Finalize problem area list and problem area definitions 2.- Gather data 3.- Assess risk for each real problem 4.-Prioritize risk by ranking them 5.- Document risk analysis 6.- Identify areas of uncertainty requiring more research/data gaps 7.- Identify environmental indicators that will help monitor risk in the future

8. RISK MANAGEMENT STEPS: 1.- Select risk factor 2.- Determine risk reduction goals for problems areas 3.- Brainstorm on activities to reduce risk for problem areas 4.- Consider barriers to implementing activities 5.- Develop actions to overcome barriers 6.- Propose action plan activities to reduce or prevent risk, schedule, measures of progress 7.- Document action plants 8.- Establish process for repeating project or updating results

9. INDICATORS Indicators show the changing conditions 1.- defining and describing the magnitude of environmental problems 2.- Providing basis for setting goals 3.- Showing progress (or lack of progress) toward set goals.

10. TYPES OF INDICATORS PRIMARY INDICATORS : Directly report the changing condition of environmental quality SECONDARY INDICATORS: Provide information about a toxicant that affects environmental conditions. May be accompanied with information explaining the link between the toxicant and the magnitude of impact TERTIARY INDICATORS: Measure management activities that address a problem(can give information about the cost of different management strategies)

11. KEY QUESTIONS IN RISK CHARACTERIZATION What are the statistical uncertainties in stimating the extent of health effects? Which population groups should be the primaty targets of protection

12. Risk Assessment. Problem Set Problem 1.- A.- Define the following terms 1.- Potency factor 2.- Reference dose 3.- Dose-Response Relationship 4.- Hazard 5.- Risk B. Provide brief answers to the following questions 1.- What are the four basic elements of risk analysis? 2.- What are the main uncertainties in risk assessment? 3.- List two areas of major uncertainty in predicting environmental concentrations of chemical contaminants. HOMEWORK

13. Problem 2.- Adidas factory (50.000 shoes at year) Dichloromethane exposure1950 workers, 30 mg/m3 Methyl Ethyl ketone exposure 3200 workers, 130 mg/m3 Nike factory, (3.800.000 shoes /year) Tetrachloroethylene exposure 2800 workers, 80 mg/m3 Investigate the listed chemicals: Check the following chemical data base: People are working 12 hours at day and 6 days a week Who is your preferred supplier of running shoes?

14. Problem 3.- The risk to a given population due to exposure to benzene (due to inhalation ) was estimated to be 10 -4. Given an individual mass of 70 kg, an inhalation rate of 20 m 3 /day. Estimate the maximum “acceptable” ambient concentration of benzene in the atmosphere. The cancer potency factor for benzene is 0.029 (mg/kg/d) -1 ).

15. Problem 4.- From one set of dose-response experiments for the chemical Chlorobore it was determined that at a dose of 2x10 -3 mg/kg/day, the lifetime cancer risk (P(d) = 1x10 -4 (i.e., the probability of cancer risk occurring is one in a population of 10000). 1.- Determine the cancer potency factor (the constant b) for the one-hit model given that the background cancer risk is 10 -7. 2.- What should be the maximum permissible dose rate (i.e., mg/kg/day) if the cancer risk is not to exceed 1x10 -6 3.- Given that the major exposure pathway is due to inhalation estimate the concentration for chlorobore in the atmosphere at the maximum acceptable risk of 1.10 -6.

16. The following equation and data may be of use to you in solving this problem: P(d) =1 – e –(a+bd) In which P(d) is the probability of cancer occurring at a dose rate of “d” (mg/Kg/day), b is the cancer potency factor (mg/kg/day)-1), and a is a constant such that P(0) is the background probability of cancer occurrence. Data: Lifetime = 70 years Inhalation Rate = 22 m 3 /day Water consumption rate = 2 liters/day Ingestion of meat = 0.3 kg/day Average mass of a person = 65 kg