Alaska State Summary Report from 2000 DOE Report to Congress on Long Term Stewardship
Did I Miss My Exit? Long Term Stewardship for Vapor Intrusion · 2017. 10. 26. · VI and Long Term...
Transcript of Did I Miss My Exit? Long Term Stewardship for Vapor Intrusion · 2017. 10. 26. · VI and Long Term...
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Did I Miss My Exit? Long Term Stewardship for Vapor IntrusionAaron P. Friedrich, MS, LPG
October 23, 2017
Indiana Chamber of Commerce2017 Environmental Conference
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Agenda
Objectives
The Basics of Vapor Intrusion (VI)
The Process of “Screening In/Out” – Entering the Highway
VI Assessment Activities – On the Highway
Challenges Related to VI Assessments – Road Construction
VI Mitigation & Long Term Stewardship – Cruise Control/Highway Exit(s)
Conclusions
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Objectives
Understand the basic science of VI and how property contamination may trigger a VI assessmentUnderstand certain aspects of the long term stewardship (LTS) life cycle and how to navigate institutional controls (ICs)Understand certain challenges related to VI & LTS on the path to closure
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Superior Signal Company, LLC
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The Basics of Vapor Intrusion
4US EPA Vapor Intrusion Technical Guide, June 2015
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Evolution of Vapor Intrusion Guidance
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1990’s 2002 2002-2010
• State Guidance development,
• Research and technical papers
2010-2013
• 1991 – J&E Model• State VI Guidance
(MA - 1993)• Superfund VI
Guidance• Hill Air Force Base
(UT)• Redfield, CO
Current
• EPA Draft Guidance (2002)
• CERCLA 5-year review,
• ITRC PVI• Final USEPA VI and
PVI guidance
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States with Regulatory Guidance1
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1 While we believe the information presented in this slide to be accurate as of September 2016, the information is not intended as advice. You should always formally discuss vapor intrusion issues with the appropriate state regulatory agency before taking action on matters associated with the vapor intrusion pathway at your sites.
States with stand alone VI guidance (draft or final)
States with guidance as part of another program (limited guidance)
States likely to rely on USEPA guidance
WA
MT
ID
OR
CA
NY
UT
CO
WY
AZNM
TX
OK
KS
NE
SD
MN
IA
MO
AR
LA
MS
TN
AL GA
FL
SC
NC
VA
WV
INIL
WI
MI
PA
NY
ME
MA
AK
KY
WA
MT
ID
OR
CA
NY
UT
CO
WY
AZNM
TX
OK
KS
NE
SD
ND
MN
IA
MO
AR
LA
MS
TN
AL GA
FL
SC
NC
VA
WV
OHINIL
WI
MI
PA
NY
VT
ME
NH
MA
RI
CT
NJ
MD
DE
AK
HI
KY
TX
FL
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Screen In/Out Assessment
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So…you know your site is contaminated….
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Preliminary Screen In/Out Assessment
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1 2 3 4
Determine if volatile chemicals
present or potentially present in
subsurface
Evaluate if prompt action needed
Develop preliminary
CSM
Evaluate readily
available data
Exit only if CLEAR evidence
that VOCs or people not
present
So…you know your site is contaminated….
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Screening In - Identifying a Completed Pathway
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1. A subsurface source of vapor-forming chemicals is present underneath or near the building;
2. Vapors form and have a route along which to migrate toward the building;
3. The building is susceptible to soil gas entry, (openings and driving ‘forces’ exist to draw vapors from the subsurface into the building;
4. One or more vapor-forming chemicals in the subsurface is present in the indoor environment; and
5. The building is occupied when the vapor forming chemical is present indoors.
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Screening In - VI Inclusion Zones
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100 feet default (laterally or vertically) - Indiana
Distance for evaluating VI should be based on site-specific factors including:
• Presence of conduits or permeable bedding
• Preferential hydrogeologic pathways
• Extensive surface covers
• Uncertainties in delineation boundaries
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Screen In/Out - IDEM’s Petroleum VOC Screening
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Flow Chart from IDEM’s Remediation Closure Guide, 2012
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Screen In/Out - IDEM’s Chlorinated VOC Screening
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Flow Chart from IDEM’s Remediation Closure Guide, 2012
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Preliminary VI Assessment Approach
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Develop CSM
Develop CSM
Identify sampling strategy
Identify sampling strategy
Collect MLECollect MLEEvaluate MLE
Evaluate MLE
Determine risks
Determine risks
Consider: • Location of
source relative to building
• Source strength• Receptors
• Proceed in a step-wise fashion
• Most often start with soil gas and/or indoor air
• Others: radon, passive, pressure differential data
• Evaluate data considering CSM
• Compare to screening levels
• Understand and expect variability
• Geology, hydrogeology• Media and chemicals of concern• Building conditions• Preferential pathways
• Evaluate human health under current or future conditions
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Detailed Analysis
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Planning & Scoping
Characterize the VI
Pathway
Sample Methods & Principles
Risk-based Screening
• Develop CSM• Determine objectives• Identify higher priority
buildings• Prepare Work Plan• Establish DQOs
• Sample collection methods
• Reduced analyte lists• Sample numbers and
frequency
• Nature & extent of sources
• Migration in vadose zone
• Building conditions (entry pathways, indoor air)
• VISLs• AFs• Modeling
A lot of variables and conditions that need to be investigated and identified
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VI Data Evaluation
Multiple Lines of
Evidence
Subsurface sources
Vapor migration and attenuation
Building conditions
Interior assessment
Background sources
Modeling
Evaluating Lines of
Evidence
Consider with CSM
Collect more data if results
inconsistent
Determine if VI Pathway Complete
Install engineering controls
Remediate subsurface
sources
No further action (pathway
incomplete)
Collect more information
Calculate Risks (if pathway complete
Consider both current and future
uses
Use full risk range with 10-6 as point
of departure
Account for background contributions
Consider short-term exposures
Each component is part of the risk-based decision processes that factor into LTS
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VI and Long Term Stewardship
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Current Focus and Emphasis on Long Term Stewardship
EPA’s National Policy on Use and Roles of ICs is to develop an IC Plan:
• Institutional Controls: A Guide to Planning, Implementing, Maintaining, and Enforcing Institutional Controls at Contaminated Sites, EPA-540-R-09-001 (Dec. 2012) [referred to as the “IC Guidance”]
• Institutional Control: A Guide to Preparing Institutional Control Implementation and Assurance Plans at Contaminated Sites, EPA-540-R-09-002 (Dec. 2012) [referred to as “ICIAP Guidance” or “IC Plan”]
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ITRC Long Term Contaminant Management (2016)
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ICs are executed to prevent certain exposures but are not considered remediation
ITRC Long Term Contaminant Management Using Institutional Controls, December 2016
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ITRC Long Term Contaminant Management (2016)
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Planning – identification of objectives; identification of parties’ roles and responsibilities; costs and funding sources; impacts on an IC’s long-term effectiveness.
Implementation – drafting, negotiation, execution, and recording. The clear identification of, and commitments to roles, responsibilities and resource needs
Monitoring and Performance Evaluation – actions and procedures to help assure that IC integrity, compliance with IC requirements, and site risk mitigation
Enforcement – actions in response to a breach. Actions can range from informal communications seeking voluntary compliance to more formal, legal action.
Modification/Termination – legal or administrative steps taken to alter or remove an IC due to a change in site characteristics, or because cleanup objectives or other IC conditions have been met.
Poses many challenges!
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LTS Challenges
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Flux in media-based screening levels
Short term exposures (e.g. TCE)
Record keeping and documentation
Management of ongoing risks (ICs and VRSI)
Change of ownership
Change in land use
Maintain controls } ICs
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Conflicting Screening Levels
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EPA asserts authority to assess/mitigate VI in non-residential settings (Section 7.4.3)
“PELs (and TLVs), however, are not intended to protect sensitive workers, may not incorporate the most recent toxicological data, and may differ from EPA derivations of toxicity values with respect to weight-of-evidence considerations and use of uncertainty factors. For these and other reasons, EPA does not recommend using OSHA’s PELs (or TLVs) for purposes of assessing human health risk posed to workers by the vapor intrusion pathway or supporting final “no-further-action” determinations for vapor intrusion arising in nonresidential buildings. Rather, EPA’s recommendations for assessing human health risk posed by vapor intrusion are set forth herein in Sections 7.4.1 and 7.4.2. “ (US EPA, 2015)
OSHA Developments
• Oct 2013 – Since OSHA's adoption of most PELs more than 40 years ago, new scientific data, industrial experience and developments in technology clearly indicate that these mandatory limits are not sufficiently protective of workers' health.
IDEM Guidance (old vs. new) vs. US EPA VISL
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VI Challenge – TCE Guidance vs. Policy
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Exposure Accelerated (ug/m3)
Action Rapid (ug/m3) Action
Resident 2 Mitigation implemented
quickly & effectiveness
confirmed promptly.
6 Mitigation implemented immediately & effectiveness confirmed before additional
exposure. Temporary relocation may be indicated.
Commercial (8 hr)
8 24
USEPA Region 9 (a)
(a) Accelerated values supported by Region 10, but averaged over 21 days and actions not specified
USEPA HQ August 27, 2014 Memo• 2 ug/m3 (RfC) identified as protective of fetal heart malformations
• Early action may be necessary at sites to protect human health
• A single exposure may be sufficient to produce an adverse effect; however, RfC for a single exposure not developed by USEPA
• No specific number for action, type of action, or timeframe for action
• IRIS provides the best toxicity information for making early action decisions
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Concern about Short Term VOC Levels
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No practical guidance to implement
• Exposure has already occurred at the time of sampling
Johnson et al. (2003) not supported by science
• Drinking water study
• Inhalation studies have not shown FHM. Results of FHM limited to this testing facility
• Concerns over dissection method
• Limited dose-response trend
Potentially significant implications:
• US EPA Guidance on 5-YR Superfund Reviews (includes tox)
• US EPA Proposed HRS Rule for VI Pathway
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IDEM Vapor Remedy Selection & Implementation (VRSI)
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February 2014
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LTS and IDEM’s VRSI - Mitigation
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Data supports the need to mitigate the pathway, so….
Active MitigationSSD
Air Purifiers
Passive MitigationBarriers
Schedule for Verification Sampling
OM&M CETCO
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IDEM VRSI – Post Mitigation Sampling
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Long Term Monitoring
IDEM’s VRSI, February 2014
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IDEM VRSI – When Does the LTS Life Cycle End?
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After you:
Reduce soil, groundwater, soil gas concentrations < health protective SLs or
Eliminate the source and potential mechanisms that may be contributing to the pathway (e.g. Preferential pathways)
Ultimately, system termination dependent on SS/IA sampling AND what ICs (if any) are necessary
Answer: Maybe Never!
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VI LTS Uncertainties - Planning & Implementation
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The longer the time period and the more onerous the OM&M, the higher the costs
Concerns related to property transfer, change of ownership, or potential change in land use
Ensuring protectiveness through financial assurance
Key: When developing ICs related to VI – Develop the future by learning from the past…
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IDEM’s IC Registry
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IDEM’s IC Registry
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IDEM’s IC Registry
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Conclusions
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VI is complex but the management of its risks is becoming easier through advanced science, stakeholder transparency, and regulatory guidance
Adhering to the 5 key components of LTS are crucial to managing long term risks related to VI
There are many effective ways to implement LTS for VI but every receptor must be treated differently
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Questions?
Aaron Friedrich, M.S., L.P.G.
8425 Woodfield Crossing BlvdIndianapolis, Indiana 46240