Environmental Health XV Risk Assessment ShuChi Chang Ph

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

Outline n n n Introduction Applications Qualitative risk assessment Quantitative risk assessment Accident situations Risk management

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

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

Comparative risks

Comparative risks

Qualitative risk assessment n n Budgetary constraint Qualitative risk assessment n n n 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

ASTDR’s public health assessment n n n 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.

Quantitative risk assessment n n n Hazard identification Dose-response evaluation Exposure assessment n n 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

Components of QRA

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

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

1 in 1, 000 risk of death

1 in 1, 000 risk of death

1 in 1, 000 risk of death

Days of life lost

Expenditures per year of life saved

EPA’s seven rules of risk communication

Key principles of risk assessment

Final exam reminders n n n n 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.