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


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

Mira Images


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

ESCLabs.com

Superior Signal Company, LLC


The Basics of Vapor Intrusion

4US EPA Vapor Intrusion Technical Guide, June 2015


Evolution of Vapor Intrusion Guidance

5

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• EPA Draft Guidance (2002)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


States with Regulatory Guidance1

6

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


Screen In/Out Assessment

7

So…you know your site is contaminated….


Preliminary Screen In/Out Assessment

8

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….


Screening In - Identifying a Completed Pathway

9

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.


Screening In - VI Inclusion Zones

10

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


Screen In/Out - IDEM’s Petroleum VOC Screening

11

Flow Chart from IDEM’s Remediation Closure Guide, 2012


Screen In/Out - IDEM’s Chlorinated VOC Screening

12

Flow Chart from IDEM’s Remediation Closure Guide, 2012


Preliminary VI Assessment Approach

13

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


Detailed Analysis

14

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


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


VI and Long Term Stewardship

16

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”]


ITRC Long Term Contaminant Management (2016)

17

ICs are executed to prevent certain exposures but are not considered remediation

ITRC Long Term Contaminant Management Using Institutional Controls, December 2016


ITRC Long Term Contaminant Management (2016)

18

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!


LTS Challenges

19

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


Conflicting Screening Levels

20

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


VI Challenge – TCE Guidance vs. Policy

21

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


Concern about Short Term VOC Levels

22

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


IDEM Vapor Remedy Selection & Implementation (VRSI)

23

February 2014


LTS and IDEM’s VRSI - Mitigation

24

Data supports the need to mitigate the pathway, so….

Active MitigationSSD

Air Purifiers

Passive MitigationBarriers

Schedule for Verification Sampling

OM&M CETCO


IDEM VRSI – Post Mitigation Sampling

25

Long Term Monitoring

IDEM’s VRSI, February 2014


IDEM VRSI – When Does the LTS Life Cycle End?

26

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!


VI LTS Uncertainties - Planning & Implementation

27

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…

Little atoms


IDEM’s IC Registry



29



30


Conclusions

31

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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32 www.erm.com

Questions?

Aaron Friedrich, M.S., L.P.G.

8425 Woodfield Crossing BlvdIndianapolis, Indiana 46240

[email protected]

Did I Miss My Exit? Long Term Stewardship for Vapor Intrusion · 2017. 10. 26. · VI and Long Term...

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