vapor intrusion at epa - astswmo – association of … · 2015-04-28 · vapor intrusion at epa...
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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
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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
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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
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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
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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
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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
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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.
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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
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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
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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
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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
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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)
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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
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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.
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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
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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
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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
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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
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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
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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)
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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
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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
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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
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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
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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
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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
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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.)
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Indoor Air SamplesIndoor Air Samples
Note, highest in spring & fall
Rightslink Copyright Clearance License No. 2114510809616
spring & fall
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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)
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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
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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)
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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,
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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
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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
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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
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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)
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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
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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
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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
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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
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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”
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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