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Environmental Health XV. Risk Assessment

Environmental Health XV. Risk Assessment

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Environmental Health XV. Risk Assessment

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  1. Environmental Health XV. Risk Assessment Shu-Chi Chang, Ph.D., P.E., P.A. Assistant Professor1 and Division Chief2 1Department of Environmental Engineering 2Division 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

  6. 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

  14. 1 in 1,000,000 risk of death

  15. 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.