21. 481 Risk management

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Risk Management
Regulatory action Decision to mitigate risk Move out of the area Change chemicals Better training Better maintenance or change process Intercepting toxic emission Do risk assessment Provide cost-benefit analysis Can be simple or very complex
CE 481 - Risk Assessment/Management
Jeff Kuo, Ph.D., P.E. jkuo@
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Definitions Hazard: material or physical condition with potential to cause harm or loss Risk: potential (probability) for an undesirable consequence to result from activities related to the hazard Risk normally in terms of expected frequency or probability and the severity or impact of the results.
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Risk Assessment - Process
Data H azard Id en tification W hat agents are p oten tially harm ful?
Dose-R esponse
sment
Exposure Assessment
H ow is intake or dose related to ad verse effects?
Risk Assessment
Characterization of the probability of potential adverse effects from human exposures to environmental hazards. Identify failure or accidents that can occur determine the approximate consequence and expected frequencies Qualitative or quantitative
Release model rate of resulting releases what form, concentration? duration Transport (Dispersion) model pathway evaluation Effect model
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Daily Dose (mg/kg-day) Dose = (C)(I)(EF)(ED)(AF) (AT)(BW) C = Concentration, I = Intake Rate
Consequences traffic school fine, insurance life handicapped cancer
Annual Risk 1 x 10-3 2 x 10-4 8 x 10-5 4 x 10-5 4 x 10-5 1 x 10-5 8 x 10-6 2 x 10-9
Types of Risk Health and safety risk (short term) Long-term health risk Environmental risk Operational risk (business-related concerns) non-compliance quality or production problem
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Risk - (Driving on highway -an example)
Risks Accidents Health Tickets Cause bad maintenance weather careless take chances noise kids on-time for class
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Dose-Response Assessment
Response
Slope = Cancer Slope Factor X X X X No Threshold, Linear at Low Doses Dose
Relationship between the level of exposure and the extent of injury Carcinogenic and noncarcinogenic effects Responses vary from death to tumors, skin irritation, respiratory effects, genetic mutation, and fetal development problems
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Risk Assessment
How to do it? Not an easy process Should be viewed as a process, not a one-time activity Hazard Identification Dose-response Assessment Environmental Pathway Evaluation Risk Characterization What to do after Risk Assessment Risk management
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Example – PE Sample Exam (ENV E)
LD50/30 refers to: (a) concentration in drinking water associated with 50% population death of 30-kg test animals (b) dose associated with 50% population death standardized to a 30 mg/(kg-d) dose rate (c) dose (via dermal exposure) associated with 50% population death of rates in 30 days (d) dose expected to cause 50% population death of an exposed population within 30 minutes
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Exposure Assessment (Environmental Pathway Evaluation)
Calculates the dose which an exposed individual receives Delineates the affected population by identifying possible exposure paths Exposure routes ingestion inhalation dermal absorption
Risk Characteristics
W ho w ill be exposed to w hat and for h ow long?
W hat effects are likely on h u m an h ea lth a n d en v iro n m e n t? Risk M anagem ent
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Risk Assessment
Why: effective decision-making tool for identifying and reducing risks. Gain benefits as much as possible, but avoid risk. When to do it? RMPP (risk management & prevention plan) site remediation (clean-up goal? discharge limit) tank removal (set up priority) Select treatment or disposal site policy formulation (THM rule)
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Exposure Duration
Body Weight Averaging Time
Water Ingestion Rate Inhalation Rate
Uncertainty in Risk Assessment
Not exact science The risk assessment process is extremely conservative in nature and utilizes measurements which are uncertain. Insufficient data or information gaps often exist in characterizing the potential risk of an agent, necessitating the need for assumptions or educated guesses.
Variable Soil Ingestion Rate
EF = Exposure Frequency ED = Exposure Duration AF = Absorption Factor AT = Averaging Time BW= body weight
Value
200 mg/day (children 1 through 6 years old) 100 mg/day (age groups greater than 6 years old) Adult - 30 years at one residence (national 90th percentile); Child - 6 years 70 kg adult; 10 kg child noncarcinogens = exposure duration carcinogens, 70 years Adult - 2 L/d; Child (1-6) 1 L/d Adults 0.83 m3/hr; Child 0.46 m3/hr