master 2018 vapor forum presentation -...

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When Vapor Intrusion Strikes –Staying Ahead of the Plume

Minnesota Brownfields Educational Forum

March 7, 2018

Welcome to the Vapor Intrusion Forum

Martha Faust – Minnesota BrownfieldsWalt Donnay – Home Safety Solutions

Executive Event Sponsor

Partner Event Sponsor

Joseph Maternowski –

Membership – Renew or Join Today

March is membership renewal month

Discounts on event registrations

Access to members-only events, networking, and tours

Read more about member benefits at mnbrownfields.org

Contact Angela Tangen at atangen@mnbrownfields or 612-710-0160

New in 2018: Brownfields Bootcamp

6-part series covering brownfield redevelopment from start to finish

Knowledge and networking for new professionals and allied fields

Monthly sessions beginning in September 2018:

Brownfield Redevelopment Primer

Site Investigations

Response Action Plans & Materials Management

Risk & Exposure

Financing

Getting the Deal Done

REGION 5 PERSPECTIVE ON VI:WHAT ARE OTHER STATES DOING?

Alyssa Sellwood, P.E.Vapor Intrusion Team Leader

Wisconsin Department of Natural ResourcesRemediation and Redevelopment

101 S. Webster Street, Madison, WI 53707Alyssa.Sel [email protected] | 608.266.3084

Minnesota Brownfields Vapor Intrusion Forum March 7, 2018

Region 5 States We talk to each other Common goal and challenges Many similarities

Vapor Intrusion in Wisconsin’s One cleanup program New VI Guidance Pathway to Closure

MESSAGE

Formed Jan 2016 Quarterly calls Environmental

Regulators Dept. of Health

Purpose Understand framework Discuss challenges Share solutions & policy

REGION 5 VI WORKGROUP

Access IssuesVI Assessments Sampling Approaches TCE Risk Risk Communication

REGION 5VI WORKGROUP TOPICS

Preemptive Mitigation Parking GaragesO&M and StewardshipAudits More….

People Access Risk Communication

Mitigation Performance verification Passive Parking Garages

Tracking properties Long-term care

REGION 5COMMON CHALLENGES

State Yes? Additional Information

Illinois Owner must agree to restrictive covenant

Michigan Uncertainty with effectiveness

Minnesota Performance verification required

Ohio Uncertainty with effectiveness

Wisconsin If a new building, test after construction

REGION 5SIMILARITIES AND DIFFERENCES

Is preemptive mitigation allowed?

State Criteria

Indiana 1 to 3 rounds(Depends on results and if worst case conditions)

Michigan 4 Quarterly Samples(More required for TCE)

Minnesota 2 seasonsOhio 2 seasonsWisconsin 2 to 3 rounds


How much sampling needed?

StateSub-slab

Data ResultSub-slab + Indoor Air

Soil Gas + J&E Model

Illinois

Indiana*

Minnesota

Ohio

Wisconsin


What data determines mitigation?

* Has a matrix for range of conditions. Remedy or indefinite monitoring required if high sub-slab with clean indoor air.


Are parking garages allowed as mitigation?

Yes, but questions remain Does ventilation pull in subslab vapor? What is optimal exchange rate for VI? Is intermittent operation ok? How to verify performance?

State Yes?Typical Requirements for

Sub-slab Depressurization Systems

Illinois Pressure field extension (PFE)

Indiana PFE and indoor air

Michigan PFE (indoor air sometimes)

Minnesota PFE and indoor air

Ohio PFE and indoor air

Wisconsin PFE (indoor air sometimes)


Is performance verification important for mitigation?


Who is responsible for O&M of mitigation?

Most states = responsible partyMichigan DEQ does all orphan sites (a lot!)Wisconsin Responsible party until closure Property owner after closure

WI PERSPECTIVEREMEDIATION & REDEVELOPMENT

One cleanup program: Hazardous cleanup USTs Spill response State-funded cleanups Brownfields

dnr.wi.gov/topic/Brownfields/

Revised January 2018 Good Table of Contents Covers all parts of VI

assessments

WI PERSPECTIVEVAPOR INTRUSION GUIDANCE

dnr.wi.gov/topic/Brownfields/Vapor.html/

Addressing Vapor Intrusion at Remediation & Redevelopment Sites in Wisconsin (RR-800)

WI PERSPECTIVEPROTECTING PEOPLE FROM VI

Can VI be screened out with existing data?

WI PERSPECTIVESCREENING

Chlorinated VOC Screening Criteria

Can vapor investigation be completed now?

Sub-slab is best Building present? Access?

Soil gas has value High confirms risk Low, may not rule out VI

Indoor air informative How urgent of response Is pathway complete today

WI PERSPECTIVESAMPLING

Is site-specific attenuation factor an option?

Allowed in non-residential Radon tracer test Reduces over-engineering Maintain building conditions Maintain land use No additional controls

WI PERSPECTIVESAMPLING

Continuous Radon Monitor

Is remediation of vapor source an option?

Is mitigation needed to address VI potential?

WI PERSPECTIVEVI MITIGATION & REMEDIATION

If new buildings, sample subslab after construction

Take advantage of opportunity during redevelopment

WI PERSPECTIVEMITIGATION OPTIONS

Is performance verification complete?

Is a Maintenance Plan in place?

WI PERSPECTIVELONG-TERM O&M

Have all property owners been notified?

Continuing Obligations

O&M of mitigation or Land use restriction Any affected property Owners are responsible

Tracked in databaseAudited randomly

RR Sites Map

WI PERSPECTIVECLOSURE OF SITES

dnr.wi.gov/topic/Brownfields/wrrd.html

Common Goal = Protection of human healthVI science applied similarly Some differences b/c of regulatory frameworkWI allows closure of sites with VI, but… No preemptive mitigation Rigorous performance verification Planning ahead with property owners Maintenance Plan Formal notification

TAKE HOME MESSAGES

REGION 5 PERSPECTIVE ON VI

Questions?

Vapor Intrusion Updates

Tim Grape MN Brownfields Vapor Intrusion Forum

March 7, 2018

When Vapor Intrusion Strikes - Staying Ahead of the Plume

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MPCA Vapor Intrusion Updates & Clarifications

1. Sub-slab Sampling Methodology Video

2. Partial building investigation/mitigation

3. BMP clarifications

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Sub-slab Sampling Methodology Video

Appendix B – Sampling Methodology https://www.pca.state.mn.us/waste/cleanup-guidance#vapor-intrusion-best-management-practices

State Contract labs providing tubing and valve set-ups for sub-slab testing.

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Sub-slab Sampling Methodology Video

Important components of sub-slab sampling include:

1. Leak testing the sample point (e.g. water dam method)

2. “Shut-In” test – confirming that the sample train connections don’t leak

3. Purging the sample train and sample point without disconnecting the sample train connections

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Partial Building Investigation/Mitigation

October 2017 - Investigation/Mitigation Decision BMP updated with Partial Building Investigation (PBI) and Partial Building Mitigation (PBM) pp 10-11

• Updates based on stakeholder feedback regarding overall approach to evaluating & mitigating larger buildings

• Includes larger residential buildings (multi-unit residential, schools) and commercial / industrial buildings

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Partial Building Investigation (PBI) Approach:

• Larger buildings - start with 30,000 ft2 for VI investigation = 8 sub-slabs

• PBI should focus on area of building near VI Area of Concern (AOC) or recognized environmental conditions (RECs)

• May need to expand VI investigation if VI AOC > 30,000 ft2

• Despite building size, ALL VOC vapor sources and RECs must be investigated for VI

• Evaluate and investigate any preferential pathways from VI AOC areas36


Partial Building Mitigation (PBM) Approach:

• Determine area of building needing mitigation based on sub-slab data from PBI

• All areas where sub-slab exceeds 33XISVs (VI AOC) require mitigation

• Mitigation area may be smaller than 30,000 ft2

• Mitigation may commence after initial round of sub-slab testing; however, 2nd seasonal round to define mitigation (VI AOC) boundary is still necessary

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BMP Clarifications

Most common VI hotline questions are about:

1. Seasonal sampling

2. Vapor investigation/mitigation approach

3. Brownfield assurances/requirements

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BMP Clarification – Seasonal Sampling

Seasonal Sampling – Are You Sure?

Temporal variability in vapor sampling with a seasonal component due to:• Groundwater table fluctuations• Soil moisture content – precipitation (or lack of)• Frost capping• Barometric pressure/wind speed

Not following seasonal sampling would result in:• Destabilization of VI decisions across all programs including Brownfields

• Liability assurances would be compromised as they would not be based on sufficient data

• MN being out of sync with EPA and other States (i.e. Region 5)39


Are the Seasonal Dates Firm?YES!!!

Non-heating season = April 1 – October 31Heating season = November 1 – March 31

WHY???“Seasonal” is not just outside temperature or snow/frost conditions.

It is not practical to monitor all of the sub-surface variables that may affect temporal variability and come up with a “worst-case scenario” for sampling.

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Does seasonal sampling apply to sub-slab and soil-gas? YES

What if the first round is non-detect? YES - 2nd seasonal round to confirm

What if the first round is >33X ISVs? NO – VI AOC is identified or mitigation

What about post mitigation verification testing?

If heating season and passing – then NO, if non-heating – then YES41

BMP Clarification – VI Investigation

What question are we trying to answer?

1. Is a VI AOC present?

• defining the boundaries of a VI AOC

2. Does this building need mitigation?

• is the building even within a VI AOC?

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Why are these questions important?

Knowing the question will assist with:

• How many samples you need

• What type of samples to collect (soil-gas and/or sub-slab)

• Where to collect the samples

• What assurance(s) you may need

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44


When do I use Appendix C?

When trying to determine if mitigation is necessary for a building that is within a VI AOC as determined by:

• shallow impacted groundwater below the building• soil-gas >33XISV w/in 100ft. of building

If I’m collecting a sub-slab within a building, do I automatically use Appx C?• No – not if evaluating a REC within the building (i.e. flame waste trap)• No – not if trying to define a VI AOC with sub-slab data (i.e. new building or lack of

space on site for soil-gas)45

VI BMP Path Forward & Stakeholder Input

46

Residential Mitigation

BMP March 2015

Investigation Mitigation Long Term O&M

Investigation and Mitigation

Decision BMP October 2017

(updated)

Commercial/ Industrial

Mitigation BMP

IN PROGRESS

Long term O&M and Future Property

Owner Notification (2019)

We Are

Here

Commercial / Industrial Mitigation BMP

Stakeholder Advisory Group • MN Brownfields

• Environmental Consultants

• Banking/Lenders

• Grant Funders

• Legal

• Real Estate – Any volunteers?47


First BMP Stakeholder Meeting is scheduled: Mid April, 2018

Public BMP development website posted yesterday featuring:

• Stakeholder group members

• Meeting agendas and discussion items

• Regular meeting notes & updates

• Draft work productshttps://www.pca.state.mn.us/waste/development-commercialindustrial-vapor-intrusion-mitigation-bmps

48


Stakeholder input improves BMP development by providing:

• Technical expertise

• Multiple perspectives

• Your needs and concerns as a program user

49


50BMP development process and timeline


Issues and questions for stakeholder advisory group• Passive Mitigation

• Vapor Barriers

• HVAC for Mitigation

• Indoor Air Filtration

• Underground Parking

• Mitigation Systems vs. Remediation Systems

• Required Verification Testing

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How can you contribute to the BMP process?

1. Contact the MPCA Vapor Specialist Team (VST)

• Email: [email protected]

• Phone: (651) 757-2040

2. Contact any Stakeholder Advisory Group Member https://www.pca.state.mn.us/waste/development-commercialindustrial-vapor-intrusion-mitigation-bmps

VIC Update

Gary KruegerMN Brownfields Vapor Forum

March 7, 2018

No Association Determination Letter

Minn. Stat. 115B.178 – Commissioner May issue determination to Requests that proposed actions will not associate Requestor with Identified Releases of Hazardous Substances

Soil gas only investigations are generally not sufficient. Soil and/or Groundwater sampling also needed, or justify not necessary.

i.e. within known PLP listed vapor plume site.

One sampling event is enough data to document an Identified Release and get a NAD

Minn. Stat. 115B.177 – Off-Site Source Determination is not limited to Groundwater Releases

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Conditions of NAD Letter

Minn. Stat. 115B.178 – Commissioner’s Determination may be subject to Reasonable terms and conditions

Conduct and report 2nd seasonal sampling event

Resolve potential vapor risks for building(s) on the property

Define the vapor impacts on property

Record appropriate institutional control

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Two “New” Vapor Assurance Letters

Completion of vapor mitigation response actions for on-site

buildings

Issued for a specific building(s)

Non-Responsible Parties only

Must have met terms/conditions of NAD

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Completion of vapor assessment

Determination that building(s) mitigation is not necessary

Non-Responsible Parties only

Must have met terms/conditions of NAD

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No changes in requirements for No Action/No Further Action letters

Apply under Technical Assistance on Voluntary Remediation application

portal

Outline request in cover/proposed actions letter

Phase One needed?

Brownfields Program Services Document

58

THANK YOU!

59

Questions

Break Time10:05-10:20

Intrusion Screening Values - ISVs

Bonnie Brooks | Research Scientist

Minnesota Brownfields - March 7, 2018

Protecting and improving the environment and enhancing human health.

ISV TSD and spreadsheet

62

• Intrusion Screening Value Technical Support Document (ISV TSD)

• Derivation of ISVs

• Concepts to consider when using ISVs

• Audience – risk assessors, toxicologist

• Does NOT replace program specific guidance

• ISV Spreadsheet• ISVs applicable to Minnesota

• Replaces 2009 ISV spreadsheet

• Replaces 2017 Interim ISV Short Guidance

• NO changes to interim ISVs, only 2009 ISVs

• NO changes to interim ISV methodology or exposure parameters

• Toxicity values may change

ISV TSD – What ISVs evaluate

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• Chronic (long-term) risks from vapor intrusion

• Exposure route

• Inhalation

• 2 sets associated with a type of building

• Residential ISVs

• Commercial/Industrial ISVs

ISV TSD – How ISVs are derived

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EPA Superfund Methodology

Cancer ISV = 10 μg/m3

Chronic noncancer ISV = 32 μg/m3

Final ISV = 10 μg/m3 based on cancer impacts

Exposure Parameters• Residential• Commercial/

Industrial

Toxicity Values• Cancer• Noncancer

ISV TSD - Expedited ISVs (EISVs)

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• Expedited ISVs (EISVs)• Higher value than ISVs

• Represent increased exposure

• Example – Residential ISVs

ISV Type Cancer Risk Noncancer Risk

ISV1E-05

1 in 100,000 excess cancer cases1

EISV 1E-04

1 in 10,000 excess cancer cases3

ISV and EISV cancer and noncancer risk

ISV – Intrusion Screening ValueEISV – Expedited Intrusion Screening Value

ChemicalISV

µg/m3

EISVµg/m3

Benzene 4.6 46

Xylene 100 310

ISV TSD – 33X ISV & 33X EISV

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• EPA’s default vapor intrusion attenuation factor

• 33X is familiar terminology - NOT how it is calculated

•33X ISV =

•33X EISV =

ISV TSD - Why TCE is treated differently(Trichloroethylene)

67

• ISVs evaluate chronic (long-term) exposure

• TCE + pregnant woman or woman that could become pregnant

• Shorter than chronic risks

• Acute (24 hr.) & short-term (30 days)

• Cardiac malformations to fetus

• Occurring in a shorter timeframe than long-term chronic risks

• Need to be evaluated in a shorter timeframe

ISV spreadsheet summary

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• Worksheets

• Overview

• Toxicity data

• BUC equations

• BUC calculations

• BUC sub-slab & soil gas worksheet

• BUC indoor air worksheet

BUC – Building use category


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• Worksheets

• Overview

• Toxicity data

• BUC equations






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• Worksheets

• Overview

• Toxicity data

• BUC equations -Residential






71

• Worksheets

• Overview

• Toxicity data

• BUC equations –Commercial/Industrial






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• Worksheets

• Overview

• Toxicity data

• BUC equations -Residential






73

• Worksheets

• Overview

• Toxicity data

• BUC equations

• BUC calculations -Residential





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• Worksheets

• Overview

• Toxicity data

• BUC equations





25 samples


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• Worksheets

• Overview

• Toxicity data

• BUC equations





• Cell remains blue with concentration in black font • Concentration = or < 33X ISV

• Cell turns orange with concentration in brown, bolded font• Concentration > 33X ISV

• Cell turns red with concentration in red, bolded font• Concentration > 33X EISV and 33X ISV


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• Worksheets

• Overview

• Toxicity data

• BUC equations





25 samples


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• Worksheets

• Overview

• Toxicity data

• BUC equations





• Cell remains blue with concentration in black font • Concentration = or < ISV

• Cell turns orange with concentration in brown, bolded font• Concentration > ISV

• Cell turns red with concentration in red, bolded font• Concentration > EISV and ISV

Thank you!

Bonnie [email protected]

651-331-6173

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master 2018 vapor forum presentation -...

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