Vapor Intrusion Technical Update Richard Ragos3.amazonaws.com/ebcne-web-content/fileadmin/pres/5-May_2013/5-3... · IA Background MassDEP Study Guide & CT DEP ... • Screening Levels

Richard Rago

Vice President Haley & Aldrich

Vapor Intrusion – Technical Update

Haley & Aldrich, Inc.

Vapor Intrusion Regulatory

Updates

22 April 2013

Presented by Richard J. Rago, Vapor Intrusion Practice Leader


Agenda

• Vapor Intrusion Basics

• Vapor Intrusion Pathway Evaluation by Various State Programs

• OSWER Final Guidance For Assessing And Mitigating The

Vapor Intrusion Pathway From Subsurface Sources To Indoor

Air (April 2013 External Review Draft)

• OUST Guidance For Addressing Petroleum Vapor Intrusion At

Leaking Underground Storage Tank Sites (April 2013 External

Review Draft)

• New Indoor Air Background Study in Massachusetts

• Considerations for practitioners


VI Pathway: Main Transport Mechanisms

• Diffusion of vapors from sources in the unsaturated zone

• Diffusion of vapors from sources in shallow ground water

• Advective/convective transport of vapors

• Vapor migration through preferential pathways

Key Point: Understanding soil and groundwater is prerequisite to

developing a VI CSM and developing a sampling strategy


VI CSM

Schuver, 2013


Other CSM considerations that may be

relevant to many sites

(Eklund, 2006)


General Approaches to Assessing

Vapor Intrusion

• EPA and many states use a tiered approach to

evaluate sites:

• Tier 1 – Simple Screen

• Are VOCs present?

• Tier 2 – Simple screen

• Are VOCs above de minimis levels?

• Tier 3 – Site-specific evaluation

Key Point: For the VI pathway to be complete, there must be a source, a

mechanism for transporting contamination, and a potential receptor.


1992.. 1996 1997 1998.. 2000 2001 2002.. 2004 2005 2006 2007 2008 2009

MassDEP

Numerical

Standards

NYS DOH

IA Background

Study

CT DEP

Numerical

Standards

CDPHE

Redfields,

CDOT Sites

MDEQ

Volatilization

Criteria

(RBSLs)

NH DES

Standards

NYSDEC

Endicott, NY

VI Project

OSWER (EPA)

MassDEP

IA Sampling

Guide & Proposed

Revisions

MDEQ

Revisions

MDEQ

TCE memo

and RRD Op

Memo No. 1

NYS DEC

Draft Policy

CA DTSC

VI Guidance

NH DES

Residential

IA Assessment

Guide

CDPHE

IA Analysis

Guide

Michigan Science

Board Evaluation

NYS DOH

IA Sampling

Guide

IDEM

NYSDOH

NHDES

ITRC

MassDEP

Internal SOP

UPVs

ASTM

EPA

Mitigation

Advisory

MDEQ

RRD Op

Memo No. 4

OSWER TCE

Memo

CTDEP

SVS SOP

CA DTSC

VIMA

SG

Advisory

NJDEP

History of VI Guidance Development


1992.. 1996 1997 1998.. 2000 2001 2002.. 2004 2005 2006 2007 2008 2009

MassDEP

Numerical

Standards

NYS DOH

IA Background

Study

CT DEP

Numerical

Standards

CDPHE

Redfields,

CDOT Sites

MDEQ

Volatilization

Criteria

(RBSLs)

NH DES

Standards

NYSDEC

Endicott, NY

VI Project

OSWER (EPA)

MassDEP

IA Sampling

Guide & Proposed

Revisions

MDEQ

Revisions

MDEQ

TCE memo

and RRD Op

Memo No. 1

NYS DEC

Draft Policy

CA DTSC

VI Guidance

NH DES

Residential

IA Assessment

Guide

CDPHE

IA Analysis

Guide

Michigan Science

Board Evaluation

NYS DOH

IA Sampling

Guide

IDEM

NYSDOH

NHDES

ITRC

MassDEP

Internal SOP

UPVs

ASTM

EPA

Mitigation

Advisory

MDEQ

RRD Op

Memo No. 4

OSWER TCE

Memo

CTDEP

SVS SOP

CA DTSC

VIMA

SG

Advisory

NJDEP

History of VI Guidance Development First Established/Discussed

Different Triggers for PHC

Not a lot happening


Recent VI Updates Provide For

Challenging Regulatory Landscape

• 6 guidance documents released or updated in 2010

• 7 guidance documents released or updated in 2011

• ~25 guidance documents released or updated since 2010

• 3 from New Jersey in the past fifteen months

• 4 from EPA in past five months


Only fourteen states remain without VI Guidance

(Many are recent; Alaska and Hawaii have VI Guidance)

States with VI Guidance

States without VI Guidance


Basic Differences Between States

• Trigger Distances

• Petroleum Hydrocarbons: a few <30 ft, some 30-50 ft, many still 100 ft

• CVOCs: a few <100 ft or >100 ft, nearly all 100 ft

• Screening Levels

• GW, Soil, Deep Soil Gas, Shallow Soil Gas/Sub-slab, Indoor Air

• VI Screening Levels (can differ over orders of magnitude)

• Attenuation Factors

• Groundwater (H): often 0.001

• Crawlspaces: often 1

• NJ shallow soil gas: 0.02, some 0.001, some 0.1

Eklund et al, 2013

OSWER VI Guidance


16 April 2013 e-announcement, emphasis

added

• “EPA is affording the public with an opportunity to provide input on its draft final vapor intrusion guidance documents. This afternoon, the Office of Solid Waste and Emergency Response released for public input two draft vapor intrusion guidance documents: a general guidance for all compounds; and one focused on petroleum hydrocarbons released from underground storage tanks. When final, these guidance documents will help ensure vapor intrusion exposure assessment and mitigation actions to protect human health are undertaken in a technically, scientifically and nationally consistent manner. The documents can be accessed at:” http://www.epa.gov/oswer/vaporintrusion.

• Public input must be submitted by May 24, 2013, at: http://www.regulations.gov; docket number: EPA-HQ-RCRA-2002-0033-007.

http://www.epa.gov/oswer/vaporintrusion

http://www.regulations.gov/


OSWER VAPOR INTRUSION GUIDANCE

• OSWER Final Guidance For Assessing And Mitigating

The Vapor Intrusion Pathway From Subsurface Sources

To Indoor Air

• November 2012 Draft Internal EPA Deliberative Document

obtained by InsideEPA.com

• April 2013 External Review Draft

• Not prescriptive like the 2002 guidance

• allows room for interpretation and professional judgment in

reaching conclusions about VI

• Flexible with no Tier I/Tier II/ Tier III screening


Elements of 2013 OSWER Draft

• Definition: “Vapor intrusion is similar to radon intrusion…”

• Statutory authority: “Protection of human health is a critical

mandate underlying several federal statutes, including …”

“On this basis, the EPA has broad authority to assess and,

if warranted, mitigate vapor intrusion in residential and

nonresidential settings…”


2013 OSWER Scope/Applicability

• “EPA recommends consideration of the Final VI Guidance when: Making

“Current Human Exposures Under Control” environmental indicator (EI)

determinations at RCRA corrective action facilities (EPA 1999a, 2002b)10 and

National Priorities List (NPL) sites under CERCLA (EPA 2008b); Undertaking

removal actions, remedial actions, pre-remedial investigations,11 remedial

investigations, and five-year reviews (FYRs)12 under CERCLA; and

Undertaking RCRA facility investigations and corrective actions and site

investigations and cleanups at federal facilities and brownfield sites.”

• “The broad concepts of this guidance generally may be appropriate when

evaluating any of a large number and broad range of vapor-forming

chemicals…”

• “chlorinated hydrocarbons (CHCs), petroleum hydrocarbons, other types of both halogenated

and non-halogenated volatile organic compounds (VOCs), elemental mercury, and radon when

it arises from uranium-or radium-bearing solid wastes in the subsurface.”

• Also includes methane references, if from natural gas transmission lines


General OSWER Approach

Considerations

• Not much of a departure from what skilled VI practitioners are already doing for risk-based pathway screening

• Establish the Conceptual Site Model (CSM) for VI

• Choose applicable Vapor Intrusion Screening Levels (VISL)

• If source medium is NAPL or unsaturated soil, then use soil gas data

• Deep soil gas data are applicable for characterizing VI and are interpreted as being representative of sub-slab conditions

• Can use modeling to support no significant VI pathway with other MLEs; most applicable to cases of future building construction


OSWER Conceptual Site Model Language

• Three conditions must exist for hazardous vapors to reach

the interior of buildings from the subsurface environment

underneath or near a building:

• A source of hazardous vapors must be present in the soil or in

groundwater underneath or near a building

• Vapors must form and have a pathway along which to migrate

toward the building

• Entry routes must exist for the vapors to enter the building and

driving forces must exist to draw the vapors into the building

• If these three conditions are present, the vapor intrusion

pathway is referred to as “complete”


OSWER Contaminants of Potential

Concern

• a chemical is considered to be “vapor-forming” if:

• molecular weight less than 200 grams per mole, vapor pressure greater than 1 milliliter of mercury, or Henry’s law constant greater than 10-5 atmosphere-meter cubed per mole; and;

• vapor concentration of the pure component exceeds 33 times the indoor air target risk level if the vapor source is in soil, or, if in groundwater, the saturated vapor concentration exceeds 1,000 times the target indoor air risk level

• “EPA recommends that these chemicals be routinely evaluated during vapor intrusion assessments conducted in accordance with the Final VI Guidance, when they are present as subsurface contaminants.”

• List includes Biphenyl, Aroclor 1221, Aroclor 1232, Naphthalene, Cyanide (CN- and HCN), Mercury

~Inverse of recommended alphas used

~Acenaphthene, Anthracene, Fluorene, 1-Methylnaphthalene, 2‐Methylnaphthalene, Pyrene, other CNs removed


OSWER Prompt Action Conditions

• Explosive conditions (one-tenth (10%) of the lower explosive limit)

• When measured concentrations exceed sub-chronic or acute toxicity values (e.g., sub-chronic inhalation reference concentrations) or regional removal management levels

• Odors reported by occupants, particularly if described as “chemical,” “solvent,” or “gasoline”

• Physiological effects reported by occupants

• Wet basements in areas where groundwater is known to contain vapor-forming chemicals


OSWER Preliminary Analysis of VI

• Two conditions, at a minimum, must be present for the VI

pathway to pose a potential human health threat

• there must be a source of vapor-forming chemicals in the

subsurface environment

• includes reference to a “primary vapor release such as from

natural gas transmission lines”

• buildings are present (or could be constructed in the future) above

or “near” the subsurface vapor source(s)

• “building” refers to a structure that is regularly occupied and

used by humans

or could be occupied and used in the future


OSWER Conceptual Site Model

Considerations

• “In general, CSMs identify the potentially exposed

populations, potential exposure routes, and potential

adverse health effects (i.e., toxicity) arising from indoor air

exposures. Therefore, the CSM also should identify and

consider sensitive populations, including but not limited to:”

• Elderly

• Women of child-bearing age

• Infants and children

• People suffering from chronic illness

• Disadvantaged populations (i.e., an environmental justice situation)”


OSWER Action Levels and Alphas

• New: “Where the aggregated carcinogenic risk to an individual based upon a reasonable maximum exposure condition for both current and future land use is less than one per ten thousand (i.e., 10-4 or one hundred per million) and the noncancer HI is less than 1, response action is generally not warranted for vapor intrusion.”

• The risk range upper boundary not a “bright line” at 10-4, and arisk estimate that is “around 10-4” may be acceptable if justified. Risk managers may also decide that risk levels less than 10-4 are unacceptable for site-specific reasons and require response actions for VI.

• Alphas:

• Groundwater = 0.001 (0.0005: semi-site-specific value for fine-grained vadose zone soils)

• sub-slab and exterior soil gas = 0.03

• crawl space =1


OSWER Investigation Considerations

• Buildings within 100 feet laterally of subsurface vapor sources

(or 100 feet vertically of underlying vapor sources) should be

considered “near” for VI investigations, assuming preferential

pathways are not present

• A “worst first” (e.g. “step out”) approach is recommended to

investigating buildings

• Allows for groundwater, soil, soil gas sampling (including

“exterior soil gas”), and crawl space air sampling

• EPA recommends exterior soil gas sampling at various depths or

several depth intervals

• Include a “near-source” soil gas sample collected immediately above

each source of contamination to help characterize the vapor source


OSWER Sampling and Risk Management

Framework

• Multiple sampling rounds recommended

• When the VI pathway determined to be incomplete, then

mitigation not generally warranted under current

conditions

• EPA recommends that site managers also evaluate whether

subsurface vapor sources that remain have the potential to pose

unacceptable VI health risks in the future if site conditions were to

change

• Response actions may be warranted to protect human health

wherever and as long as subsurface vapor sources remain that

have the potential to pose unacceptable health risks in the future

due to VI

OUST Petroleum VI Guidance


EPA Petroleum Vapor Intrusion (PVI)

Guidance

• Guidance For Addressing Petroleum Vapor Intrusion At

Leaking Underground Storage Tank Sites

• November 2012 EPA Office of Underground Storage Tanks;

Redline Strikeout Draft document obtained by InsideEPA.com

• April 2013 EPA OUST External Review Draft

• “…PVI guidance focuses on underground storage tanks,

typically located at gas stations and non-marketing

facilities regulated under Subtitle I of the Solid Waste

Disposal Act.”

• Increased flexibility


PVI Document Has Narrow Focus

• PVI associated with three classes of chemicals:

• PHCs found in gasoline, diesel, and jet fuel (e.g., benzene,

trimethylbenzenes)

• Other vapor-forming chemicals found in petroleum (e.g., methyl

tertiary-butyl ether (MTBE) and other fuel additives)

• Methane from anaerobic biodegradation of PHCs and other

constituents of petroleum fuels, especially ethanol


OUST PVI Document: PVI Unlikely

• Indicates that few confirmed occurrences of PVI at

petroleum sites are reported in literature

• Adds references that there are no reported cases of vapor

intrusion from dissolved-phase petroleum hydrocarbon

sources vertically separated from building foundations

• Suggests that most likely scenarios for PVI to occur are

shallow PHC sources directly beneath buildings and

mobile LNAPL or groundwater plumes with high

concentrations of PHCs in direct contact with buildings


PVI Document Lateral Exclusion Distance

• Determine Whether Further Investigation Is Unnecessary:

• EPA references that a vertical separation distance of 5.4 feet from

dissolved sources and 13.5 feet for LNAPL sources adequate to

eliminate the potential for PVI

• Because of the difficulty in accurately measuring precise

distances, EPA recommends vertical separation distances of 6 feet

for dissolved and 15 feet for LNAPL sources


OUST: Further investigation for PVI may

be unnecessary:

• low levels of soil contamination (clean soil; i.e., LNAPL is

not present as mobile or residual material) or groundwater

contamination:

• Groundwater ≤ 30 mg/L TPH (gasoline) or benzene ≤ 5 mg/L or

soil ≤ 250 mg/kg TPH (gasoline) or benzene ≤ 10 mg/kg, and

vertical separation distance between PHC and the lowest point of

a building foundation, basement, or slab is 6 feet or more

• high levels of soil or groundwater contamination (i.e.,

LNAPL is present):

• groundwater > 30 mg/L TPH (gasoline) or benzene > 5 mg/L or

soil > 250 mg/kg TPH (gasoline) or > 10 mg/kg benzene, and the

vertical separation distance between PHC and the lowest point of

a building foundation, basement, or slab is greater than 15 feet


PVI Document: Biodegradation

• At short distances from source, PHCs become negligible

primarily due to aerobic biodegradation; literature reported

that PHCs vapors from dissolved plume were almost

completely degraded within 1 meter above the water table

and that transport of PHC vapors may only be significant if

the source is LNAPL

• For large buildings and/or where there is extensive

impermeable surface covering, soil vapor samples

recommended if concern that conditions may impede flux

of oxygen to subsurface and create an oxygen shadow

• oxygen content should be > 1% throughout thickness of

clean, biologically active soil for aerobic biodegradation

Massachusetts Study of Indoor Air

Background VOCs and APH in

Schools, Offices, and Municipal

Buildings


Benzene Residential TV: 2.3 ug/m3

Median: 1.6 ug/m3 Median: 1.8 ug/m3

Residential background data


New Massachusetts Indoor Air

Background Study

• Focused on Commercial/Municipal Offices and Schools

• Designed with input from MassDEP and EPA

• Conducted by Haley & Aldrich, Alpha Analytical, SKC, and

eurofins/Air Toxics LTD

• Acknowledgements to Andy Rezendes, Linda Coyne, and Heidi

Hayes



Background Study (continued)

• Sampling in winter using Summa canisters with 24-hour

flow controllers

• Analysis via TO-15 (full scan and SIM) and MassDEP CAM APH

• Side by side sampling using SKC Ultra III Passive

Samplers

• Analysis via TO-17

• Initial round of sampling completed

• 10 samples collected in schools

• 10 samples collected in offices



Background Study – preliminary results

• Tetrachloroethylene detected in 100% of office samples and

60% of school samples

• Concentrations ranging from 0.136 ug/m3 to 9.02 ug/m3

• Benzene detected in 100% of office samples and 100% of

school samples


• Trichloroethylene detected in 1 office sample at 0.441

ug/m3

• 1,2-dichloroethane detected in 90% of office samples and

60% of school samples



Possible Implications of Federal Changes

and Updates

• EPA guidance documents may result in greater

inconsistency

• Potentially unreasonable standard of care expectations

• States may follow suit and allow increased or decreased

flexibility

• PRP sites may be grouped with the OSWER or OUST

document (or both)

• States may consider more conservative trigger distances

for PHCs


Closing

• Please review the draft EPA OSWER VI and draft EPA OUST

PVI documents

• http://www.epa.gov/oswer/vaporintrusion/documents/vaporIntrusion-final-

guidance-20130411-reviewdraft.pdf

• http://www.epa.gov/oust/cat/pvi/petroleum-vapor-intrusion-review-draft-

04092013.pdf

• Public input must be submitted by May 24, 2013

• Please provide comments on the documents or request an extension at

http://www.regulations.gov; docket number EPA-HQ-RCRA-2002-0033-007

• http://www.regulations.gov/#!submitComment;D=EPA-HQ-RCRA-2002-0033-

0090

• Please consider your office building for the indoor air

background study

• http://www.haleyaldrich.com/downloads/rago_viupdates.pdf

http://www.epa.gov/oswer/vaporintrusion/documents/vaporIntrusion-final-guidance-20130411-reviewdraft.pdf









http://www.epa.gov/oust/cat/pvi/petroleum-vapor-intrusion-review-draft-04092013.pdf























http://www.haleyaldrich.com/downloads/rago_viupdates.pdf


Thank You!

Richard Rago

Vapor Intrusion Practice Leader


860.290.3115 tel.

617.719.6128 cell [email protected]

mailto:[email protected]

Documents

Vapor Intrusion Technical Update Richard Ragos3.amazonaws.com/ebcne-web-content/fileadmin/pres/5-May_2013/5-3... · IA Background MassDEP Study Guide & CT DEP ... • Screening Levels