1. Environmental Health XV. Risk Assessment Shu-Chi Chang, Ph.D., P.E., P.A. Assistant Professor 1 and Division Chief 2 1 Department of Environmental Engineering 2 Division of Occupational Safety and Health, Center for Environmental Protection and Occupational Safety and Health National Chung Hsing University Friday, June 22, 2007

2. Outline Introduction Applications Qualitative risk assessment Quantitative risk assessment Accident situations Risk management

3. Introduction Definition of risk Personal Environmental health Risk assessment What can go wrong How likely What consequence Risk management Uncertainties

4. Applications Two basic concepts Cost/benefit analysis Still hard to communicate

5. Comparative risks

7. Qualitative risk assessment Budgetary constraint Qualitative risk assessment Qualitative characterization where health risks are identified but not quantified Qualitative risk estimations where chemicals are ranked or classified by broad categories of risk Semi-quantitative approaches where effect levels were used in combination with uncertainty factors to establish “ safe ” exposure level EPA ’ s five categories of toxic agents ATSDR ’ s public health assessment

8. ASTDR ’ s public health assessment 10 key substances: (1) lead, (2) arsenic, (3) mercury, (4) vinyl chloride, (5) benzene, (6) cadmium, (7) polychlorinated biphenyls, (8) chloroform, (9) benzo(b)fluoranthene, (10) trichloroehtylene. 7 priority health conditions: (1) birth defect and reproductive disorder, (2) cancers, (3) immune function disorders, (4) kidney dysfunction, (5) liver dysfunction, (6) lung and respiratory diseases, and (7) neurotoxic disorders 5 categories of risks: (1) urgent public health hazards, (2) public health hazards, (3) indeterminate public health hazards, (4) no apparent public health hazards, and (5) no public health hazards.

9. Quantitative risk assessment Hazard identification Dose-response evaluation Exposure assessment The chemical and physical characteristics of the toxic agent Identification of the person to be protected Recognition of the difference in the exposure measured and the dose that will actually be received by the exposed individuals Risk characterization

10. Components of QRA

11. Accident situations Risks associated with accidents Four steps Accident scenario development and screening Consequence assessment Uncertainty and sensitivity assessment Regulatory-compliance assessment

12. Risk management Acceptable levels of risk Trigger levels for environmental or occupational controls Superfund site remediation: risk based decision Key decision factors Risk communication Inadequate manner of scientific community Examples: days of life lost, per year of life saved, EPA ’ s rules of risk communication Reporting risk distribution Reflect the uncertainty associated with QSA Examples: key principles

13. 1 in 1,000,000 risk of death

16. Days of life lost

17. Expenditures per year of life saved

18. EPA ’ s seven rules of risk communication

19. Key principles of risk assessment

20. Final exam reminders Cover all the materials taught in this term ~50% from the homework Open-book, 2 hours No discussion but you are allowed to share resources You may leave the classroom after you sign the attendance sheet. Return your final exam to Room 502, Civil and Environmental Building, NCHU before noon, 06/29/2007. Hand in the exam write-up in person to Dr. Shu-Chi Chang Your final score will be posted on the bulletin board before July 2, 2007.