risk assessment pt2kkelly/es_website/ra_presentationpt2.pdfrisk characterization: carcinogens...

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


5.2$mg/min

10$m3

Room


5.2$mg/min

10$m3

Room

Air$exchange$rate$of$2$per$hour

10#m3 10#m3


5.2$mg/min

10$m3

Room


10#m3 10#m3="20"m3/hr


5.2$mg/min

10$m3

Room


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


ChemicalEstimated

dose (mg/kg-day)

Reference dose







Total


/

//

1.13


ChemicalEstimated

dose (mg/kg-day)

Reference dose







Total


Decreased weight HI = 1.13 >1 possibly unacceptable exposure Kidney HI = 10.1 > 1 possibly unacceptable

/

//

1.13


ChemicalEstimated

dose (mg/kg-day)

Reference dose







Total


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


Chemical

Estimated dose

(mg/kg-day)

Slope factor

(mg/kg-day)-1

IELCR Target


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


Chemical

Estimated dose

(mg/kg-day)

Slope factor

(mg/kg-day)-1

IELCR Target


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)








Not all environmental regulations use the same types of standards









CAA “protect public health with an adequate margin of safety”









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

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









People selectively listen to your message.









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






FCC, Title V permit


Refinery process, air regulation






FCC, Title V permit


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


Risk of Becoming a News Story


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


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.

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