Risk Assessment Pt2 K.E. Kelly University of Utah
Risk Assessment Pt2K.E. Kelly
University of Utah
Reminders/Updates— I will post the solu.on to HW#1 on Tuesday evening. -‐ Presenta.on topics and schedules are up. Please review the schedule. I have done my best to address your schedule conflicts. I also just had a speaker reschedule. Now, the first presenta.ons are next week:
-‐ 9/20 VW Emissions Scandal, Troy Petrie, Jason Henderson -‐ 9/22 Winter-‐.me ozone in Utah's Uinta basin, Emir
Rahislic -‐9/22 Electric versus gasoline vehicles, Kyle Branch -‐ 9/22 Biofuels, McKenna Buck, Mike Morgan -‐ We can discuss when your outlines are due
Reminders/Notes
-‐ I removed the Williams presenta.on from the class website as the speaker’s request. It is now in Canvas (Williams99.pdf).
-‐ Example fact sheet on hydraulic fracturingThanks to Tony Long
-‐ Steven Cano -‐ remote learning is looking for a project #1 parter
Example 1a - Breathing TolueneA refinery worker works in a shop that has a constant input of toluene from the parts cleaning tanks of 5.2 mg/min. What is the worker’s intake rate. (Stock - Flow Problem). We are going to look at risk, but first we need to determine the concentration in the room.
Equilibrium concentration
Toluene releasefrom tanks
room, Vol = 10m3 & air change rate = 2 per hr
Flow out, ventilation
Example 1 - Need concentration
Example 1 - Need concentration
5.2$mg/min
10$m3
Room
Example 1 - Need concentration
5.2$mg/min
10$m3
Room
Air$exchange$rate$of$2$per$hour
10#m3 10#m3
Example 1 - Need concentration
5.2$mg/min
10$m3
Room
Air$exchange$rate$of$2$per$hour
10#m3 10#m3="20"m3/hr
Example 1 - Need concentration
5.2$mg/min
10$m3
Room
Air$exchange$rate$of$2$per$hour
10#m3 10#m3="20"m3/hr
Ctoluene = 5.2 mgmin ∗ 60minhr ∗ hr
204m3 = 15.6 mg4m3
Example 1b - Toluene Intake
• Concentration (CA) of toluene in the room 15.6 mg/m3
• Average adult body weight (BW) = 70 kg
• Inhalation rate (IR) = 0.53 m3/hr
• Exposure frequency (EF) = 260 days/yr
• Exposure duration (ED) = 30 years
• Averaging time (ΔT) = 10,950 days = 30 years * 365 days/yr
• Absorption factor is assumed to be 1 and isn’t shown in equation.
Example 1 - Intake
!"#$%&' ()%) − +$, = ./01234' ∗ !6 ∗ 78 ∗ 79
:;' ∗ ∆=
!"#$%&' ()*)+,-. =
01.34546∗8.19'
46:; ∗<=
:;>?@∗<38
>?@@A?;∗98'.B-CD
E8'*)'∗931'>?@F@; '∗98'.B-CD'="2.02 ()
*)+,-.
Example 2 - Ingestion of Contaminants in Drinking Water
An adult drinks water containing 0.05 mg/l benzene and 0.5 mg/l toluene for 30 years. Estimate the intake rate of each.
Benzene is a carcinogen, and toluene is a non-carcinogen.
Note benzene and toluene solubility in water are approximately 1.8 g/l and 0.5 g/l, respectively.
Calculate the intake rate.
Cw = concentration in the water (mg/l)
IR = ingestion rate (2 l/day)
EF = exposure frequency (days/yr)
ED = exposure duration (yr)
BW= body weight (70 kg)
ΔT = averaging time
For non-carcinogens ΔT = 365 days/year * exposure duration
For carcinogens ΔT = lifetime (70 years) * 365 days per year
Example 2 - Ingestion of Contaminants in Drinking Water
Example 2
0.5 mg/l toluene (non-carcinogen)
0.05 mg/l benzene (carcinogen)
!"#$%&' ()%) − +$, = ./' ∗ !1 ∗ 23 ∗ 24
56' ∗ ∆8
!"#$%&' ()%) − +$, =
0.05()1 ∗ 2' 1+$, ∗ 365
+$,,&$6 ∗ 30',&$67
70'%)' ∗ 365' +$,7,6 '∗ 70',&$67'= 6.12':'10;< ()
%) − +$,
!"#$%&' ()%) − +$, =
0.5()1 ∗ 2' 1+$, ∗ 24
ℎ6+$, ∗ 365
+$,,&$6 ∗ 30',&$69
70'%)' ∗ 365' +$,9,6 '∗ 30',&$69'= 0.014 ()
%) − +$,
Risk Characterization
Risk = Toxicity * Exposure
Slightly different calculations for cancer vs. non-cancer effects
Risk Characterization: Non-CarcinogensCompare estimated dose with the reference dose (RfD)
HQ = Intake/RfD
Intake - to convert RfC to a dose:Inhalation dose (mg/kg-day) = RfC (mg/m
3) * 20 m
3/day /
70 kg
If HQ < 1, typically not a concern. If HQ>1, need further study.
You can sum several simultaneous exposures to the same target organ/endpoint
Hazard Index (HI) = HQ1 + HQ2 + HQ3+…
1.13
Risk Characterization: Non-Carcinogens Cumulative Effects
ChemicalEstimated
dose (mg/kg-day)
Reference dose
(mg/kg-day)HQ Target
Toluene 2.02 0.2 10.1 kidney
o-cresol 0.05 0.05decreased
body weight neurotoxicity
xylene 0.025 0.2decreased
body weight mortality
Total
RfD and target targets from: EPA IRIS
/
1.13
Risk Characterization: Non-Carcinogens Cumulative Effects
ChemicalEstimated
dose (mg/kg-day)
Reference dose
(mg/kg-day)HQ Target
Toluene 2.02 0.2 10.1 kidney
o-cresol 0.05 0.05decreased
body weight neurotoxicity
xylene 0.025 0.2decreased
body weight mortality
Total
RfD and target targets from: EPA IRIS
/
//
1.13
Risk Characterization: Non-Carcinogens Cumulative Effects
ChemicalEstimated
dose (mg/kg-day)
Reference dose
(mg/kg-day)HQ Target
Toluene 2.02 0.2 10.1 kidney
o-cresol 0.05 0.05decreased
body weight neurotoxicity
xylene 0.025 0.2decreased
body weight mortality
Total
RfD and target targets from: EPA IRIS
/
//
1.13
Risk Characterization: Non-Carcinogens Cumulative Effects
ChemicalEstimated
dose (mg/kg-day)
Reference dose
(mg/kg-day)HQ Target
Toluene 2.02 0.2 10.1 kidney
o-cresol 0.05 0.05decreased
body weight neurotoxicity
xylene 0.025 0.2decreased
body weight mortality
Total
RfD and target targets from: EPA IRIS
/
//
1.13
Risk Characterization: Non-Carcinogens Cumulative Effects
ChemicalEstimated
dose (mg/kg-day)
Reference dose
(mg/kg-day)HQ Target
Toluene 2.02 0.2 10.1 kidney
o-cresol 0.05 0.05decreased
body weight neurotoxicity
xylene 0.025 0.2decreased
body weight mortality
Total
RfD and target targets from: EPA IRIS
Decreased weight HI = 1.13 >1 possibly unacceptable exposure Kidney HI = 10.1 > 1 possibly unacceptable
/
//
1.13
Risk Characterization: Non-Carcinogens Cumulative Effects
ChemicalEstimated
dose (mg/kg-day)
Reference dose
(mg/kg-day)HQ Target
Toluene 2.02 0.2 10.1 kidney
o-cresol 0.05 0.05decreased
body weight neurotoxicity
xylene 0.025 0.2decreased
body weight mortality
Total
RfD and target targets from: EPA IRIS
Decreased weight HI = 1.13 >1 possibly unacceptable exposure Kidney HI = 10.1 > 1 possibly unacceptable
Added o-cresol & xylene as an example - did not calculate dose
/
//
How does a dose of a carcinogen effect humans?
Cancer slope factors (CSF) estimate the risk of cancer associated with exposure to a carcinogenic or potentially carcinogenic substance. It is an upper bound, approximating a 95% confidence limit, on the increased cancer risk from a lifetime exposure to an agent.
http://en.wikipedia.org/wiki/Cancer_slope_factor
How does a dose of a carcinogen effect humans?
Cancer slope factors (CSF) estimate the risk of cancer associated with exposure to a carcinogenic or potentially carcinogenic substance. It is an upper bound, approximating a 95% confidence limit, on the increased cancer risk from a lifetime exposure to an agent.
http://en.wikipedia.org/wiki/Cancer_slope_factor
CSFs are developed using models that include data from animal studies at higher concentrations and epidemiological data on human effects.
Incremental probability of the occurrence of cancer over a lifetime as a result of exposure to the agent.
Incremental Excess Lifetime Cancer Risk (IELCR) = Cancer Slope Factor * Lifetime Average Daily Dose
Cumulative Total Risk = IELCR1 + IELCR2 + IELCR3 + ….
Risk Characterization: Carcinogens
Risk Characterization: Carcinogens Cumulative Effects
Chemical
Estimated dose
(mg/kg-day)
Slope factor
(mg/kg-day)-1
IELCR Target
Benzene 6.12 x 10-4 0.029 1.8 x 10-5 Kidney
MED 7 Liver
MEDD 0.7 Liver
Total Kidney
RfD and target targets from: EPA IRIS with some modifications for the example MED: methyl ethyl death; MEDD: methyl ethyl double death
*
1.8 x 10-5
Risk Characterization: Carcinogens Cumulative Effects
Chemical
Estimated dose
(mg/kg-day)
Slope factor
(mg/kg-day)-1
IELCR Target
Benzene 6.12 x 10-4 0.029 1.8 x 10-5 Kidney
MED 7 Liver
MEDD 0.7 Liver
Total Kidney
RfD and target targets from: EPA IRIS with some modifications for the example MED: methyl ethyl death; MEDD: methyl ethyl double death
*
*
*
1.8 x 10-5
Risk Characterization: Carcinogens Cumulative Effects
Chemical
Estimated dose
(mg/kg-day)
Slope factor
(mg/kg-day)-1
IELCR Target
Benzene 6.12 x 10-4 0.029 1.8 x 10-5 Kidney
MED 7 Liver
MEDD 0.7 Liver
Total Kidney
RfD and target targets from: EPA IRIS with some modifications for the example MED: methyl ethyl death; MEDD: methyl ethyl double death
*
*
*
1.8 x 10-5
Risk Characterization: Carcinogens Cumulative Effects
Chemical
Estimated dose
(mg/kg-day)
Slope factor
(mg/kg-day)-1
IELCR Target
Benzene 6.12 x 10-4 0.029 1.8 x 10-5 Kidney
MED 7 Liver
MEDD 0.7 Liver
Total Kidney
RfD and target targets from: EPA IRIS with some modifications for the example MED: methyl ethyl death; MEDD: methyl ethyl double death
*
*
*
1.8 x 10-5
Risk Characterization: Carcinogens Cumulative Effects
Chemical
Estimated dose
(mg/kg-day)
Slope factor
(mg/kg-day)-1
IELCR Target
Benzene 6.12 x 10-4 0.029 1.8 x 10-5 Kidney
MED 7 Liver
MEDD 0.7 Liver
Total Kidney
RfD and target targets from: EPA IRIS with some modifications for the example
Kidney IELCR = 1.7 x 10-5 > 10-6 = possibly unacceptable exposure Liver IECLR = 1.4 x 10-5 > 10-6 = possibly unacceptable exposure The risk of unacceptable exposure can vary between 1: 10,000 and 1: 1 million. For this example, I use 1 in 1 million.
MED: methyl ethyl death; MEDD: methyl ethyl double death
*
*
*
1.8 x 10-5
Risk Assessment and PolicyUnderpinning many health and environmental regulations:
Clean Air Act (hazardous air pollution regulations)
Clean Water Act (governs water discharge regulations)
OSHA regulations (PELs)
Resource Conservation and Recovery Act (Superfund)
Safe Drinking Water Act (drinking water standards)
Toxic Substances Control Act (PCBs, asbestos, and lead-based paint rules)
Risk Assessment and PolicyUnderpinning many health and environmental regulations:
Clean Air Act (hazardous air pollution regulations)
Clean Water Act (governs water discharge regulations)
OSHA regulations (PELs)
Resource Conservation and Recovery Act (Superfund)
Safe Drinking Water Act (drinking water standards)
Toxic Substances Control Act (PCBs, asbestos, and lead-based paint rules)
Not all environmental regulations use the same types of standards
Risk Assessment and PolicyUnderpinning many health and environmental regulations:
Clean Air Act (hazardous air pollution regulations)
Clean Water Act (governs water discharge regulations)
OSHA regulations (PELs)
Resource Conservation and Recovery Act (Superfund)
Safe Drinking Water Act (drinking water standards)
Toxic Substances Control Act (PCBs, asbestos, and lead-based paint rules)
Not all environmental regulations use the same types of standards
CAA “protect public health with an adequate margin of safety”
Risk Assessment and PolicyUnderpinning many health and environmental regulations:
Clean Air Act (hazardous air pollution regulations)
Clean Water Act (governs water discharge regulations)
OSHA regulations (PELs)
Resource Conservation and Recovery Act (Superfund)
Safe Drinking Water Act (drinking water standards)
Toxic Substances Control Act (PCBs, asbestos, and lead-based paint rules)
Not all environmental regulations use the same types of standards
CAA “protect public health with an adequate margin of safety”
Pesticides can be licensed if they do not cause “any unreasonable risks to man or the environment taking into account the economic, social and environmental costs and benefits of the use of any pesticide”
HW2
You now should have all of the information you need for HW2.
Costs & Benefits of the CAA 1990 - 2020
Cases prevented (2020)
Adult mortality – particles 230,000
Infant mortality – particles 280
Mortality – ozone 7100
Chronic bronchitis 75,000
Acute myocardial infarction 200,000
Asthma exacerbation 2,400,000
Emergency room visits 120,000
Lost school days 5,400,000
Lost work days 17,000,000
From: EPA 2011
Costs & Benefits of the CAA 1990 - 2020
Cases prevented (2020)
Adult mortality – particles 230,000
Infant mortality – particles 280
Mortality – ozone 7100
Chronic bronchitis 75,000
Acute myocardial infarction 200,000
Asthma exacerbation 2,400,000
Emergency room visits 120,000
Lost school days 5,400,000
Lost work days 17,000,000
From: EPA 2011
Costs & Benefits of the CAA 1990 - 2020
Cases prevented (2020)
Adult mortality – particles 230,000
Infant mortality – particles 280
Mortality – ozone 7100
Chronic bronchitis 75,000
Acute myocardial infarction 200,000
Asthma exacerbation 2,400,000
Emergency room visits 120,000
Lost school days 5,400,000
Lost work days 17,000,000
Costs: equipment and operations Benefits: avoided deaths and disease (avoided health-care costs). Estimates for the value of a life are challenging:
lost wages $7 - $9 million
From: EPA 2011
Communicate with stakeholders about levels of health and environmental risk, including: the significance of health and environmental risks decisions, actions, or policies to control the risks.
In general, we think of risk = toxicity * exposure), but the public may have a different view:
Alternatively: Risk = Hazard and Outrage
Or: Risk = Hazard and Values/Emotions
Risk Communication
From WHO Report on Risk Communication by Sue Lang, Lorna Fewtrell and Jamie Bartram http://www.who.int/water_sanitation_health/dwq/iwachap14.pdf
Challenge: Dealing with Diverse Stakeholders
Engineers and Toxicologists - 1 in 1 million risk of dying from cancer
Regulators - this level of emissions will not contribute to significant deterioration of air quality
Public - Is this safe for my children to play on the playground located within a mile of the refinery?
Challenge: risk is qualitative
Risk estimates are based on models with inherent uncertainty and a variety of assumptions.
Particularly challenging for rare and potentially high-impact events.
Risk assessment depends on judgement, from scoping the analysis, selecting endpoints, to estimating exposure.
Challenge: risk is qualitative
Risk estimates are based on models with inherent uncertainty and a variety of assumptions.
Particularly challenging for rare and potentially high-impact events.
Risk assessment depends on judgement, from scoping the analysis, selecting endpoints, to estimating exposure.
Everyone (even an engineer) is wrong sometimes.
Communication StrategiesCredibility. Engage early and build trust, limit outrage factor.
Context. Your context should confirm your message. Try to engage media as an ally.
Content. Your message must be meaningful and relevant to your audience.
Clarity. Use analogies that are clear. The broader your audience, the simpler your message.
Consistency. Focus on repetition with variation.
Channels. Different audiences require different target media. Let audience know where to get additional information.
Accessibility. Don’t make it difficult to participate/access information. Offer the ability to meet in person if possible.
Avoid overstatements
Communication StrategiesCredibility. Engage early and build trust, limit outrage factor.
Context. Your context should confirm your message. Try to engage media as an ally.
Content. Your message must be meaningful and relevant to your audience.
Clarity. Use analogies that are clear. The broader your audience, the simpler your message.
Consistency. Focus on repetition with variation.
Channels. Different audiences require different target media. Let audience know where to get additional information.
Accessibility. Don’t make it difficult to participate/access information. Offer the ability to meet in person if possible.
Avoid overstatements
People selectively listen to your message.
Communication StrategiesCredibility. Engage early and build trust, limit outrage factor.
Context. Your context should confirm your message. Try to engage media as an ally.
Content. Your message must be meaningful and relevant to your audience.
Clarity. Use analogies that are clear. The broader your audience, the simpler your message.
Consistency. Focus on repetition with variation.
Channels. Different audiences require different target media. Let audience know where to get additional information.
Accessibility. Don’t make it difficult to participate/access information. Offer the ability to meet in person if possible.
Avoid overstatements
People selectively listen to your message.
Remaining silent can be a very risky strategy.
Choice of WordsNegative connotation
or confusing Positive connotation
PhD pharmotoxicologist qualified, expert
government third party
abbreviations, jargon 8th grade reading level
FCC, Title V permit
conservative estimate
Choice of WordsNegative connotation
or confusing Positive connotation
PhD pharmotoxicologist qualified, expert
government third party
abbreviations, jargon 8th grade reading level
FCC, Title V permit
conservative estimate
Refinery process, air regulation
Choice of WordsNegative connotation
or confusing Positive connotation
PhD pharmotoxicologist qualified, expert
government third party
abbreviations, jargon 8th grade reading level
FCC, Title V permit
conservative estimate
Refinery process, air regulationLess than xyz,
independent, objective, unbiased
Using Graphics
Do a preflight with stakeholders/sample audience.
Label all axes and objects. Start the axes with zero if possible.
Provide text explanations.
Using Graphics
Do a preflight with stakeholders/sample audience.
Label all axes and objects. Start the axes with zero if possible.
Provide text explanations.
Meet in person when possible
Choosing your Messenger
Source More trustworthy
Health professional 1
Consumer organizations 2
Independent scientists 3
Government 4
Industry 5
From WHO Report on Risk Communication by Sue Lang, Lorna Fewtrell and Jamie Bartram http://www.who.int/water_sanitation_health/dwq/iwachap14.pdf
Risk of Becoming a News Story
From WHO Report on Risk Communication by Sue Lang, Lorna Fewtrell and Jamie Bartram http://www.who.int/water_sanitation_health/dwq/iwachap14.pdf
Likelihood of becoming a major news story increases if the following are prominent:
Questions of blame
Alleged secrets and/or attempted cover ups
Human interest angle, i.e., heroes, villains, victims
Links to high-profile issues or personalities
Conflict
Does the story foreshadow further problems
Potential for widespread hazard
Strong visual impact (picture of injured, black cloud of smoke)
Links to sex or a crime
Stericycle $2.3 million fine and move its facility to move to Tooele
Supplementary Slides
Typical stakeholdersGovernment (federal, state, city and county organizations)
Subject matter experts (scientists engineers)
Environmental groups
Unions and groups concerned with worker health
Community organizations
Business and professional organizations (manufacturers association, chamber of commerce, etc.)
Goals of Engaging StakeholdersBuild:
Trust
Understanding
Credibility
Satisfaction
Anticipate concerns, be prepared for an event.
Don’t wait until you have a crisis on your hands
From WHO Report on Risk Communication by Sue Lang, Lorna Fewtrell and Jamie Bartram http://www.who.int/water_sanitation_health/dwq/iwachap14.pdf
Section 812 of the Clean Air Act
Requires EPA to assess the costs and benefits associated with the Clean Air Act, including:
estimating the hazards associated with air pollutants regulated under the CAA
using dose-response curves to estimate health effects
using exposure estimates to determine the health impacts
characterize uncertainties
perform a cost-benefit analysis
Risk Assessment and Policy
Permissible Exposure Limit (PEL)
OSHA regulation for workplace exposure
PELs are designed to protect workers against the health effects of exposure to hazardous substances. PELs are regulatory limits on the amount or concentration of a substance in the air. They may also contain a skin designation. OSHA PELs are based on an 8-hour time weighted average exposure.
https://www.osha.gov/dsg/topics/pel/
Permissible exposure limits (PELs) are addressed in specific standards for the general industry, shipyard employment, and the construction industry.
Threshold Limit ValuesAIGH - is a level to which it is believed a worker can be exposed day after day for a working lifetime without adverse health effects
Often seen on MSDS, gives an indication of toxicity.
TLV is an estimate based on the known toxicity in humans or animals of a given chemical substance
Changes over time
Recommended
MSDSsMaterial safety data sheets provide workers and emergency personnel with
procedures for handling substance in a safe manner (i.e., use, disposal, PPE)
Chemical, physical, and toxicological properties (bp, mp, toxicity, reactivity, health effects, etc.)
OSHA requires that MSDSs are available to employees for potentially harmful substances handled in the workplace.
MSDSs must also be available to local fire departments and emergency planning officials.
Sandman on FracturingPluses, minuses and tradeoffs
Can you think of any pluses, minuses, or concerns?
Strategy for industry
selling valid pluses;
rebutting invalid minuses; and
acknowledging valid minuses.