Review of June 2010 Supplemental

Human Health Risk Assessment

Onondaga Lake Superfund Site

5/6/2013 1

SCA Buffer Zones and

Surrounding Communities

2002 Baseline HHRA

Risk due to Fish Ingestion Exposure

Reasonable Maximum Exposure (RME) Cancer Risk values ranging from 2.4 to 7.8 per 10,000 (also shown as 2.4 to 7.8 x 10-4) due to PCBs, dioxins/furans and to a lesser degree arsenic.

RME non-cancer Hazard Index – exceeded the EPA target level of 1.0 with values of 18 for adults and 28 for children, primarily due to PCBs and methylmercury.

2002 Baseline HHRA (Continued)

Risks due to Sediment/Soil /Surface Water Exposure

RME cancer risks for most recreational

exposure pathways (e.g. swimming, wading, boating) other than fish ingestion were within EPA’s acceptable target range (1 additional incidence of cancer in a population of 10,000 to 1 in 1,000,000).

All RME non-cancer risks were below the

target level of 1.0. No target levels were exceeded for exposure

to surface water.

2002 Baseline Risk

Assessments for

Onondaga Lake

2010 Supplemental

Evaluation of Sediment

Consolidation Area

Baseline and Supplemental Risk

Assessments

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HHRA Process

Data Evaluation/Hazard Identification What chemicals are present at levels of concern?

Exposure Assessment Who might be exposed?

How often?

How long?

Toxicity Assessment What are the health effects associated with exposure

to the chemicals of potential concern?

Risk Characterization What are the overall risks from exposure?

What are the uncertainties?

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Steps of Hazard Identification

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No

Chemical of

potential concern

for air (27) Chemical of potential concern

for sediment (38)

Definitely

Identified?

Detected

>5%?

No

Yes

Yes

Ch

emical N

ot In

clud

ed

No

Maximum >

risk-based

level?

Is Chemical

Volatile?

Yes

Yes

No

Chemical

has a

Toxicity

Value?

Sediment Consolidation Area:

Exposure Scenarios Evaluated Offsite exposure to chemicals in air from sediments

Onsite direct contact with chemicals in sediments: Hypothetical failure scenario—assumes people contact sediments

(ingestion and skin contact)

Evaluates exposure to chemicals that might

volatilize from sediments/water during

sediment management and dewatering in

the SCA and migrate beyond the SCA

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(inhalation)

Exposure Assumptions Health protective RME assumptions applied

Hypothetical On-Site scenario: Exposure to sediments

released through catastrophic failure of SCA (included

at request of community)

Adult, adolescent, and child exposure

Assumed people would come onto SCA daily and

contact sediments via ingestion and dermal contact

45 days of exposure assumed

Offsite scenario: Exposure to volatile chemicals in air

from processing sediments for disposal at SCA

Assumed exposure 350 days per year, 24 hours per

day for 5 years (length of the remedial action)

Assumed adults, adolescents, and children exposed

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Toxicity Assessment

Considers noncancer health effects and,

if appropriate, cancer endpoints

Toxicity information comes from EPA-

approved, peer-reviewed sources

Integrated Risk Information System

Provisional Peer Reviewed Toxicity Value

Database

Other sources such as ATSDR, CalEPA,

other states

5/6/2013 10

Hypothetical Failure On-Site

Scenario – Sediments

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Data Management Used only data

from cores having

length >= 50% of

dredge cut

Samples fully

beneath dredge

cut excluded

330 sample

locations from

Preliminary Design

Investigation and

RI

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Length-Weighted Average (LWA)

Calculation

Chemical concentrations averaged for

each core segment for the length of

the core up to the anticipated depth of

dredging for that location to develop

LWA.

LWAs combined to derive exposure

point concentrations for onsite direct

contact.

5/6/2013 13

Off-Site Exposure Scenario –

Inhalation

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Inhalation Risk Analysis Approach

Step 1: Identify appropriate chemicals to consider for this exposure scenario

Are considered “volatile”;

Have an inhalation toxicity value; and

Included even if not detected in wind tunnel / bench testing

Step 2: Identify regulatory criteria to be enforced at site boundary:

Lower of either State or EPA risk-based concentrations for worker scenario (cancer-based values adjusted to 5-year time frame)

5/6/2013 15

Inhalation Risk Analysis Approach

(Continued)

Step 3: Identify site boundaries where air

quality criteria will be enforced and closest

residential locations in every direction

Step 4: Based on achievement of air quality

criteria at the work zone perimeter, US EPA

Air Dispersion model, AERMOD, used to

predict potential maximum air concentrations

at receptors (homes).

Step 5: Used predicted maximum air

concentrations as Air Pathway EPCs.

5/6/2013 16

Inhalation Risk Analysis Approach (Continued)

5/6/2013 17

Maximum Predicted Air Impacts (ug/m3) at Work

Perimeter and Residential Receptor Boundaries

5/6/2013 18

Unit Dispersion Model Summary

Year Peak

Fenceline

Concentration

(ug/m3)

Peak Receptor

Concentration

(ug/m3)

Peak to Peak

Ratio

2006 297 70 4.24

2007 314 64 4.91

2008 351 73 4.81

2009 330 81 4.07

Average 4.51

5/6/2013 19

Supplemental HHRA Results

5/6/2013 20

Cancer Risk Estimates: Offsite Air

5/6/2013 21

Adults Adolescent Children Primary Chemicals

4x10-6 4x10-6 4x10-6 Ethylbenzene;

naphthalene

Estimate is well within acceptable risk

range indicating:

No adverse effects would be expected

Key factors in air estimate:

– Use of highest modeled annual average

concentration for each chemical

– Assumes 350 day/24-hr exposure for 5 yrs

– Includes numerous chemicals that were not

detected in wind tunnel testing

Noncancer Risk Estimates:

Offsite Air

Estimates are within acceptable levels

indicating:

No adverse effects would be expected

Key factors:

Use of highest modeled annual average

concentration for each chemical

Assumes 350 day/24-hr exposure for 5 years

Includes numerous chemicals that were not

detected in wind tunnel testing

5/6/2013 22

Cancer Risk Estimates: SCA Direct Contact,

45-day Residential Scenario

5/6/2013 23

Adults Adolescent

(6–16)

Children

(2–6)

Children

(0–2) Primary Chemicals

1x10-6 3x10-6 1x10-5 3x10-5 PAHs, Chromium (as Chromium VI)

Estimates are well within acceptable risk range

indicating:

No adverse effects would be expected

Key factors in direct contact estimate:

– SCA plan includes layers of security, but failure

scenario was evaluated

– Assumes people coming onto Wastebed 13 daily,

resulting in ingestion and dermal contact for 45

days/yr for people of all ages (e.g., children 0-2 yrs)

Noncancer Risk Estimates:

Hypothetical Sediment Exposure

Estimates are within acceptable levels

indicating:

No adverse effects would be expected

Key assumptions:

multiple layers of containment fail allowing

people to come into contact with sediments

people coming onto wastebed daily,

resulting in ingestion/dermal contact for 45

days/yr for people of all ages

Incorporates conservative estimates of

toxicity, chemical form 5/6/2013 24

Principal Uncertainties Likely

Overestimate Risks

All mercury results assumed to be

methylmercury

Chromium assumed to be in hexavalent

form for samples where speciated data

was not available

Two of 37 Cobalt sample locations had

much higher LWA levels than the other

locations and represent < 2% of dredge

volume

5/6/2013 25

Conclusions

Health-protective exposure assumptions applied:

Offsite exposure to contaminants that could

migrate from the site in air during the operation of

the SCA

Onsite exposure to sediments within the SCA in

hypothetical failure scenario

These are both reasonable maximum estimates

5/6/2013 26

Conclusions (Continued)

Resulting risk estimates and hazard indices were

within acceptable levels:

No adverse effects would be expected

SCA will not result in unacceptable risks

SCA will be closely monitored

Supplemental HHRA can be used for risk

management.

5/6/2013 27

Online Documents

http://www.epa.gov/region2/superfund/n

pl/onondagalake/docs.html

Supplemental HHRA

Supplemental HHRA Public Meeting

PowerPoint

Supplemental HHRA FAQs

5/6/2013 28

Questions Brief overview of the HHRA process

Origins of the risk estimates used in the report

What are the non-cancer health risks that were

evaluated?

Is there potentially greater danger to residents in

being exposed to "acceptable" concentrations of

chemicals over a shorter period of time as

opposed to being more evenly spread over the

course of the year?

5/6/2013 29

Questions (Continued) Does the LWA approach used to estimate

contaminant concentrations in sediment samples

(used as basis to include/exclude chemicals from

study) and/or the fact that all samples were not

analyzed for all chemicals create potentially

unaccounted for uncertainty in the study?

Discuss the hazard index > 1 for non-carcinogenic

inhalation exposure

What are your thoughts on the health concerns

being expressed by nearby residents?

5/6/2013 30

Questions (Continued)

What is the projected health effects from

displacing 2.6 tons of mercury from the lake

bottom to WB13?

How long will the stuff be dangerous to humans

and animals?

Will it ever disappear or will it be trapped in the

bag storage?

How are the residues generated in the WTP being

managed?

Discuss the hazard index > 1 for non-carcinogenic

inhalation exposure.

5/6/2013 31