Vapor Intrusion at EPA Regulatory Update & Current Activitiesg y p

ASTSWMOASTSWMO Remediation & Reuse Symposium:

Portland ORPortland, ORMay 13, 2010Presented by:

Henry Schuver, DrPHUSEPA Offi f R C ti & RUSEPA – Office of Resource Conservation & Recovery

See: http://iavi.rti.org & www.envirogroup.com/vaporintrusion

Recent Report from EPA’s Office of Inspector General

• In December 2009 EPA’s Office of the Inspector General released an• In December 2009, EPA s Office of the Inspector General released an evaluation report: Lack of Final Guidance on Vapor Intrusion Impedes Efforts to Address Indoor Air Risks

• The Inspector General made four recommendations: p1) Identify and publicly report the portions of OSWER’s November 2002 draft vapor intrusion guidance that remain valid and the portions that should be updated [EPA response - August 2010]2) Issue final vapor intrusion guidance(s) [EPA response – Nov. 2012]3) Train EPA and State staff and managers and other parties on the newly updated, revised, and finalized guidance document(s) [EPA response initiate by May 2013][EPA response - initiate by May 2013]4) Finalize toxicity values for TCE and PCE in the IRIS database [EPA response - TCE December 2010, PCE July 2010]

Office of Solid Waste and Emergency Response

Inspector General Recommend that our final vapor intrusion guidance(s) that incorporates information on:

• Updated toxicity values.• A recommendation(s) to use multiple lines of evidence in evaluating and

making decisions about risk from vapor intrusion.g p• How risk from petroleum hydrocarbons should be addressed • How the guidance applies to Superfund Five-Year reviews. • When or whether preemptive mitigation is appropriate.e o et e p ee pt e t gat o s app op ate• Operations and Maintenance, the termination of the systems, and when

Institutional Controls and deed restrictions are appropriate.

Office of Solid Waste and Emergency Response

Approach for Developing Final VI Guidance

• Launch Vapor Intrusion website (April 2010)• Launch Vapor Intrusion website (April 2010) http://www.epa.gov/oswer/vaporintrusion/– Portal for information about our VI efforts– Resources for environmental professionals and the publicResources for environmental professionals and the public

• Identify aspects of the 2002 draft that will be updated (summer 2010)• Seek public input through a range of venues (beginning summer 2010 –2011)• Conduct cross agency and interagency reviewConduct cross agency and interagency review • To the extent possible, we will release interim guidance and supporting

documents in advance of the final guidance document (fall 2012)

Office of Solid Waste and Emergency Response

Some Preliminary Comments on VI i B fi ld i 1in Brownfield settings - 1

• Persons involved in real property development p p y pare NOT protected for VI by having a 'clean bill of health' from:– EPA’s All Appropriate Inquiries (AAI) rule, and/or – ASTM’s E1527 Phase I Standard, and/or even– ASTM’s E2600 (recently finalized) VaporASTM s E2600 (recently finalized) Vapor

Encroachment Guide

• Use of E2600 is purely discretionary & even if E2600 was used persons conducting a AAI and/or E1527 have no clear obligation to consider and include the E2600 results in their reports

• A durable regulatory solution to this such as modifying theA durable regulatory solution to this, such as modifying the AAI rule to include VI, would be a long regulatory battle

Some Preliminary Comments on VI i B fi ld i 2in Brownfield settings - 2

• Technically Difficult (Expensive & Slow) to AssessTechnically Difficult (Expensive & Slow) to Assess– Existing buildings– Pre-construction (even worse)

• Relatively easy (Inexpensive & Quick) to prevent VI in d l t iredevelopment scenarios:

• EPA’s Brownfields Primer on VI • EPA’s Engineering Issues paper on VI Mitigationg g p p g

– It is time for a “preemptive” policy for all Brownfield settings?» More on this at the end of this presentation» More on this at the end of this presentation

Office of Inspector General (OIG) R d i #1 R i 2002Recommendation #1: Review 2002• Identify and publicly report:Identify and publicly report:

– portions of OSWER’s November 2002 draft pvapor intrusion guidance that

– remain valid

and the portions that• and the portions that

– should be updatedshould be updated.

Overview of Some Changes in our Understanding: 2002 – 2010

• Variability y

– Subsurface Effects

Building Effects– Building Effects

– Atmospheric Effects

– Uncertainty (the “unknown regressor”)

• Complexity

• Predictability (of indoor air)

• Single vs. Multiple - Lines of Evidence

Note on Specific 2002 TextNote on Specific 2002 Text

• A good deal of the specific text in the draft 2002A good deal of the specific text in the draft 2002 document “remains valid” but also:

» many areas can be identified as portions that:

– “should be updated” – e.g., through replacementg g p

– And others that are

– “less-than-ideally suited / complete” – e.g., could be modified to improve and/or make more complete

A Draft Review of 2002 Draft Guidance: Evaluating the Vapor Intrusion to

Indoor Air PathwayIndoor Air Pathway from Groundwater and Soils

Some Preliminary CommentsUsing:

EPA-TIO Internet Seminar (Training) Slides f F b 11 & 12 2003from Feb. 11 & 12, 2003

The Following Slides Highlight:The Following Slides Highlight:• Areas we are considering:g

– “should be updated” – e.g., through replacement

» &

“less-than-ideally suited / complete”– less-than-ideally suited / complete – e.g., could be modified to improve &/or make complete

» Highlighted with dashed red underline-strikethrough

Text boxes will outline the bases for changes

2002 VI Guidance 3 Tiers of Screening3 Tiers of Screening

OSWER’s draft-Vapor Intrusion Guidance (Part III-C)

• 1 - Primary – (Q1, Q2, Q3) These terms will

lik l b difi d t(Q1, Q2, Q3)

• 2 - Secondary

likely be modified to be more accurately descriptivey

– (Q4 & Q5)

• 3 - Site-Specific Pathway Assessment – (Q6)(Q6)

Tier 1- Primary ScreeningOSWER’s draft-Subsurface Vapor Intrusion Guidance

• “quickly identify … any potential exists”

• Q1 Chemicals with Volatility & Toxicity?• Q1 Chemicals with Volatility & Toxicity?• Q2 Are Buildings Near?• Q3 Immediate Action Warranted?• Q3 Immediate Action Warranted?

• If not “incomplete” proceed to• If … not … incomplete … proceed to Secondary Screening Volatility criteria

may be amended, and many Toxicity #s are outdated

Table 1 (for Q1)

VVapor pressure may also be considered, e.g., for NAPL/soil sources

1 A chemical is considered sufficiently toxic if the vapor concentration of the pure component (see Appendix D) poses an incremental lifetimecancer risk greater than 10 -6 or a non-cancer hazard index greater than 1.2 A chemical is considered sufficiently volatile if its Henry’s Law Constant is 1 x 10-5A chemical is considered sufficiently volatile if its Henry s Law Constant is 1 x 10atm-m3/mol or greater (US EPA, 1991).3 Users should check off compounds that meet the criteria for toxicity and volatility and are known or reasonably suspected to be present.

Tier 2- Secondary ScreeningOSWER’s draft-Subsurface Vapor Intrusion Guidance

– “we recommend … using all available lines of evidence”

• Q4 Generic Media-specific Conc.

• Q5 Semi-Site-Specific Models

We likely want to do more than ‘recommend’ this time

Secondary Screening – Question 4M di S ifi T t C t tiMedia-Specific Target Concentrations

• Evaluation of available indoor air data.– Risk-based indoor air target screening levels.

• Generic screening of available groundwater data• Generic screening of available groundwater data.– Groundwater target screening levels.– Conservative empirical attenuation factor (1/1000).

• Generic screening of available soil gas data.– Shallow soil gas (<= 5 ft below foundation level) and

deep soil gas (> 5 ft below foundation level) screening levelsdeep soil gas (> 5 ft below foundation level) screening levels. – Conservative shallow and deep soil gas empirical attenuation factors

(1/10 & 1/100).2010 database shows ~ 50% of soil gas has less attenuation than this value

1.0E+00

1.0E+01

1.0E-02

1.0E-01

Gas

AF

Max

95th%

50th%

5th%

1.0E-04

1.0E-03Soil

G 5th%

Min

1.0E-06

1.0E-05

CHCs in  Bacground 

StatisticResidences Screen2010

gIndoor Air Screen2010

Min 5.0E‐06 1.3E‐04

5% 9.4E‐05 6.0E‐045% 9.4E 05 6.0E 0425% 2.1E‐03 2.2E‐0350% 1.6E‐02 1.8E‐0275% 8.4E‐02 1.2E‐0195% 3.6E‐01 8.5E‐01Max 3.5E+00 3.5E+00

17

N 176 74N (IA > RL) 176 74N (IA < RL) 0 0No. of Si tes 13 10

Q4 Observed AttenuationQ4 Observed Attenuation

Allowed a single line ofAllowed a single line of evidence (SLE) screen-out with default attenuation factors for:factors for:

Groundwater Only “recommended” also using soil gasalso using soil gas

Soil Gas But only if a soil source

Secondary Screening – Question 5

– Semi-site specific screening using Concerns over

Uses Models for Single Line of Evidence (SLE) ‘screen outs’

Semi site specific screening using limited site data.

• Soil type

Concerns over the precision of model-based SLE

• Depth to source

Att ti f t b d

SLE predictions of indoor air concentrations – Attenuation factors based on

Johnson-Ettinger Model.• Not applicable to all sites

using these two inputs, for “secondary” • Not applicable to all sites

• Attenuation factors vary with soil type and depth to vapor source

screen outs)

Variability in 2010 database; case experience >2002; radon models/lessons

Secondary Screening – Question 5Att ti F tAttenuation Factors

Figure 3b- DRAFTVapor Attenuation Factors - Ground Water to Indoor Air Pathway

Model as SLE & 2010 database doesVapor Attenuation Factors - Ground Water to Indoor Air Pathway

Basement Foundations

1.0E-02

database does not appear to support the use of these model-

1.0E-03

nuat

ion

Fact

or

7.0E-045.0E-043.0E-042 0E 04

of these modelbased predictions (IA)as a SLE for

1.0E-04

Vapo

r Atte

2.0E-04

groundwater and these two site-specific

1.0E-05

Depth to Contamination from Foundation (m)

Sand Sandy Loam Loamy Sand Loam

0 5 10 15 20 25 30 parameters

e.g., ~ 25% has less attenuation y y

than the circled value (5.0E-4)

Secondary Screening – Question 5Att ti F tAttenuation Factors

Figure 3a- DRAFT Model as SLEgVapor Attenuation Factors - Soil Vapor to Indoor Air Pathway

Basement Foundations

1.0E-02

Model as SLE exit, & 2010 database shows >75%

1.0E-03

n Fa

ctor

2.0E-03

7.0E-04

4.0E-04

of soil gas data has less attenuation

1.0E-04

apor

Atte

nuat

ion

2.0E-04 than this min. circled value (2.0E-03);

1.0E-05

Depth to Contamination from Foundation (m)

Va

0 5 10 15 20 25 30

and the model curves only predict even

Sand Sandy Loam Loamy Sand Loammore attenuation

1.0E+00

1.0E+01

1.0E-02

1.0E-01

Gas

AF

Max

95th%

50th%

5th%

1.0E-04

1.0E-03Soil

G 5th%

Min

1.0E-06

1.0E-05

CHCs in  Bacground 

StatisticResidences Screen2010

gIndoor Air Screen2010

Min 5.0E‐06 1.3E‐04

5% 9.4E‐05 6.0E‐045% 9.4E 05 6.0E 0425% 2.1E‐03 2.2E‐0350% 1.6E‐02 1.8E‐0275% 8.4E‐02 1.2E‐0195% 3.6E‐01 8.5E‐01Max 3.5E+00 3.5E+00

AEHSSpring 2010H. Dawson US EPA 22

N 176 74N (IA > RL) 176 74N (IA < RL) 0 0No. of Si tes 13 10

1.E+04

Alpha ~ 2E-3

1.E+02

1.E+03

ion

(ug/

m3) EPA Data (IA > RL)

Alpha = 1.0

Alpha = 1E-1

1.E+00

1.E+01

r Con

cent

rati

Alpha = 1E-2

Alpha = 1E-3

1 E 03

1.E-02

1.E-01

Indo

or A

ir

Alpha = 1E-4

Alpha = 1E-5

1.E-031.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08

Soil Gas (ug/m3)

AEHSSpring 2010H. Dawson US EPA 23

1.E+06

1.E+04

1.E+05

1.E+03

b (u

g/m

3)

1.E+01

1.E+02

Subs

lab

1.E+00

AEHSSpring 2010H. Dawson US EPA

1.E-011.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06

Soil Gas (ug/m3) 24

1.0E+00

1.0E+01

1.0E-02

1.0E-01

1.0E 00

n Fa

ctor

Max

95th%

50th%

1.0E-04

1.0E-03

Atte

nuat

io 50th%

5th%

Min

1.0E-06

1.0E-05

1.0E-07

Statistic Groundwater Soil Gas Subslab CrawlspaceMin 8.6E‐07 1.3E‐04 1.6E‐04 1.0E‐01

5% 7 6E‐06 6 0E‐04 4 7E‐04 1 7E‐015% 7.6E 06 6.0E 04 4.7E‐04 1.7E 01

25% 3.5E‐05 2.2E‐03 1.7E‐03 3.2E‐01

50% 1.1E‐04 1.8E‐02 4.3E‐03 4.4E‐01

75% 2.5E‐04 1.2E‐01 9.2E‐03 8.3E‐01

95% 1.5E‐03 8.5E‐01 1.7E‐01 9.2E‐01

Max 4.3E‐02 3.5E+00 9.4E‐01 1.0E+00

AEHSSpring 2010H. Dawson US EPA 25

N 607 74 260 35N (IA > RL) 607 74 260 35N (IA < RL) 0 0 0 0No. of Sites 21 10 11 4

Tier 3: Site-Specific Pathway AssessmentAssessment

Primary Defining Characteristics of Q6

• Site-specific mathematical modeling, for:EI approach Outdated

– EI determinations

Selecting buildings for interior samples

EI approach Outdated –Only used to prioritize VI exposures before 2005

– Selecting buildings for interior samples

• Interior samplingInterior sampling– Sub-slab– Indoor airIndoor air

Q6Q6 Interior Samples Flow Chart from Guidance

Model-only based SLE screen t i i t f i t iouts inappropriate even for interim,

e.g., Environmental Indicator (EI) determinations

(esp. after failing earlier screens)

Note Screen out with a single line of evidence using Indoor Air would be health protective (i.e., indoor air concentrations < concern)

Although, if air is contaminated (i.e., screen-in) and the source of vapors is not VI (mitigation would not change indoor air conc.)

Indoor Air SamplesIndoor Air Samples

Note, highest in spring & fall

Rightslink Copyright Clearance License No. 2114510809616

spring & fall

Steck 2005Residential Radon Risk Assessment: How well

Indoor Air Samples

Residential Radon Risk Assessment: How well is it working in a high radon region?

Data ‘really’ < i< screening level

Data ‘looks’ <

(2 + 4 day = Short Term)

Data ‘looks’ <screening level, but it is NOT(2 + 4 day = Short Term)

FIGURE 1EPA’s Perspective on Risks from Residential Radon ExposureRADON Risks“Indoor radon … the most serious environmental carcinogen which the EPA must address for the general public” Puskin 1989

Health-based studies (2005) required 1 yr

general public Puskin 1989

Pop. Risk* ~0.020000(4pCi/L)

long samples

20,000 Lung Cancers/yrBut: Complacency & Costs

Jalbert, 2004

* adult cancer adult cancer

Zones

From Frumkin, H. et al. The same VI pathway

Zones Based on indoor air & geology

Copyright ©2001 American Cancer Society

,CA Cancer J Clin 2001;51:337-344.

p y

Real ‘background’ for chemical VI

With chemical VI you get BOTH

Appendix A: Data QualityAppendix A: Data Quality We will likely raise these points earlier and t th i A A

• Screen outs – “definitive data” or “multiple lines” • OSWER “expects” approved Qual Assur (QAPP)

stronger than in App. A

• OSWER expects approved Qual. Assur. (QAPP)• Conceptual Site Model (CSM) is key• Data Quality Objectives (DQO) rule (Table 1)Data Quality Objectives (DQO) rule (Table 1)

– State Problem– Identify: Decision, Inputs, Boundaries, Decision Rules, Tolerable Error

Limits– Optimize data collection

• VOC Analytical Methods (15), web-links, PQL, costsVOC M th d A l t Li t( )• VOC Methods Analyte List(s)

Appendix B: Conceptual Site Si ifi tlModel Significantly supplemented by the Conceptual Model Scenarios (CMS)

• Three Dimensional ‘Picture’– Sources (potential pathways connecting?)

Scenarios (CMS) document

– Receptors (Current & Future)• Dynamic (modify with new information)

Additi l id ti Ni l O tli d• Additional considerations – Nicely Outlined• Guidance (& pathway documentation):

Soil Screening Guidance: Users Guide Attch A– Soil Screening Guidance: Users Guide – Attch. A. – Risk Ass. Guid. Super. Vol. 1 – Planning Table 1.– Site Conceptual Exposure Model Builder (SCEM) web– Additional References – UST, Brownfields, Eco,

Cumulative,

Appendix F: Empirical Attenuation Factors (by Dr. Dawson)

Largely being replaced by 2010 VI Database document

• 15 sites – 274 chemical residence combos• Residence w/o confounding indoor sources

• Groundwater to Indoor Air – AF observed

• Soil Gas-to-Indoor Air – AF observed

• BTEX vs Chlorinated Hydro Carbon AF• BTEX vs. Chlorinated Hydro-Carbon – AF differences

• Reliability Assessment – Dr. H. Dawson’s presentation

Appendix H: Community Involvement (by Colo. DPH&E)

Likely to be updated / supplemented by more recent experiences

• 5 Key Principles

Likely to be updated / supplemented by more recent experiences

• Proactive, Listen, Take the time, Change plans, Explain

– Get to know communityMailing list (for all interested parties)– Mailing list (for all interested parties)

– Inform stakeholders (w/ appropriate experts)– Develop and Implement Participation Planp p p

– Written permission for sampling, speak with no responders

– Conduct samplingC– Communicate results

• Occupied Dwelling Ques. – 43 Ques. Survey

Appendix I: “Background” (i.e., Non-subsurface sources) (by NJDEP)Significantly updated by 2010 Background Indoor Air document

• IAQ “difficult to interpret” w/o “careful consideration”• High variability among homes – some “users”• Inspection prior to sampling (cleaner, paint, glue, etc.)• Ratios of C-O-C conc. can help distinguish source

P i d I d Ai & S il l i• Paired Indoor Air & Soil-gas sample comparisons• Gradients of conc. within homes (up, down, across ?)

Indoor conc > s bs rface concentration ? ( / AF?)• Indoor conc. > subsurface concentration ? (w/ AF?) • CERCLA Role of Background – background risk real• Colorado Post remediation data shows background• Colorado – Post remediation data shows background• MADEP – Literature values + judgment

• see MADEP Vapor Guidance on web

Great introduction toGreat introduction to Vapor Intrusion

Major Points:

-Early consideration of VI is always better

-Pre-construction cost savings

- VI need not prevent re-developmentp

http://www.brownfieldstsc.orgSee New Publications

(EPA 542 R 08 001 2008)(EPA 542-R-08-001, 2008)

EPA’s Brownfields VI PrimerEPA s Brownfields VI Primer

• Builds on the scientific conceptsBuilds on the scientific concepts developed in the Conceptual Model Scenarios (CMS) document:( )

– where the building’s presence can changethe distribution of subsurface gasesthe distribution of subsurface gases

– where attempts to predict VI into future or p pto-be-modified buildings raises significantassessment and prediction challenges

Brownfields VI Primer contBrownfields VI Primer cont.

• Brownfields redevelopers managep genvironmental risk, – including that due to vapor intrusion:

A d h ld id d i i i i– And should consider designing engineering controls to mitigate for the potential of VI before new buildings are constructed

• Multiple Benefits:– Address the uncertainty in both site characterization and

the toxicity of contaminantsOften more cost effective to mitigate potential VI in– Often more cost-effective to mitigate potential VI in advance of construction than to conduct the extensive sampling necessary (to fully assess future bldg risks)

– Typically more cost-effective to incorporate VI mitigation measures during the design/build phase than to retrofit

An Engineering g gForum & ORD Collaboration

(Nov. 2008)

Addresses approaches &approaches & technologies to mitigate VI problems for RPMs, OSCs, and other site managers

Includes QA &Includes QA & Performance Verification

Available at: http://www.epa.gov/nrmrl/pubs/600r08115/600r08115.pdf

Pressure Differential Monitoring to Verify Disruptionto Verify Disruption

of the Vapor Intrusion Pathway

An Alternative to Vapor Sampling for Brownfields Redevelopment

William Service

NC Department of Environment and Natural Resources p

Division of Waste Management

Developer Offers Mitigation in Lieu f S liof Sampling

• Contaminated soil removalContaminated soil removal• Passive sub-slab ventilation in new construction

– Can be made active by installation of blowers on ventCan be made active by installation of blowers on vent stacks

• Installation of a membrane vapor barrier • Venting system and barrier underlie the entire

building footprint• Developer considers indoor vapor sampling to

verify system performance a “deal breaker”

Compromise is DevelopedCompromise is Developed

• NC DENR requires verification of systemNC DENR requires verification of system performance and interruption of VI pathwayp y

• Use pressure differential monitoring to verify interruption of the VI pathwayy p p y

• Developer asserts that building pressurization will create adequate p qpressure differential with the passive system