Environmental Health XV. Risk Assessment
Shu-Chi Chang, Ph.D., P.E., P.A.Assistant Professor1 and Division Chief2
1Department of Environmental Engineering2Division of Occupational Safety and Health,
Center for Environmental Protection and Occupational Safety and Health
National Chung Hsing University
Friday, June 22, 2007
Outline
Introduction Applications Qualitative risk assessment Quantitative risk assessment Accident situations Risk management
Introduction
Definition of risk Personal Environmental health
Risk assessment What can go wrong How likely What consequence
Risk management Uncertainties
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
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.
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
Accident situations
Risks associated with accidents Four steps
Accident scenario development and screening
Consequence assessment Uncertainty and sensitivity
assessment Regulatory-compliance assessment
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
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.