Vapor Intrusion Assessments Program considerations and comments on U.S. EPA s Technical Guides Tom Yoder Product Manager

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1 Vapor Intrusion Assessments Program considerations and comments on U.S. EPA s Technical Guides Tom Yoder Product Manager October 5,

2 The migration of volatile chemicals from the subsurface into overlying buildings. 2

3 Vapor Intrusion Chemicals of Concern The two most common classes of chemicals of concern for indoor air vapor intrusion include chlorinated solvents (CHCs) and petroleum hydrocarbons (PHCs). Other volatile chemicals of concern, may also contribute to indoor air vapor intrusion. ~ PHCs typically degrade biologically in groundwater as well as in unsaturated soil zones. This aerobic biodegradation can be substantial and limit the potential for petroleum vapor intrusion (PVI). ~ In contrast, biodegradation of CHCs is anaerobic, which is generally slower than aerobic biodegradation of PHCs. This limited biodegradability is to some degree responsible for the greater observed prevalence of chlorinated solvent vapor intrusion (CVI) when compared with PVI.

4 Petroleum Vapor Intrusion (PVI) In the presence of oxygen, Petroleum hydrocarbons biodegrade more readily than chlorinated solvents. / EPA Technical Guide For Addressing Petroleum Vapor Intrusion At Leaking Underground Storage Tank Sites June, 2015

5 Vapor Intrusion Timeline EPA OSWER finalizes Vapor Intrusion Guidance 2015 EPA OUST and ITRC work to publish Petroleum Vapor Intrusion Guidance 2014 OSWER revises and works to finalize 2002 Draft Vapor Intrusion Guidance 2013 ASTM D Standard Practice for Active Soil Gas Sampling in the Vadose Zone for VI ASTM E Standard Guide for Vapor Encroachment Screening in Real Estate NY Publishes Guidance, Re-opens 1400 NFR Sites OSWER replaces 2001 RCRA Guidance Redfield Rifle Site and CDOT Site 1998 J&E model published Core environmental regulations enacted RCRA, TSCA, CERCLA, HSWA, SARA ITRC Publishes Vapor Intrusion Guidance States begin addressing Vapor Intrusion: MA, CT, CA Some States Publish VI Guidance 2008 EPA Publishes Attenuation Factor Database Other States and organizations issue draft or final guidance. Florida draft, interim Petroleum VI (PVI) EPA s Final Guidance on VI and PVI is published. 5 Modified from: M. Traister, O Brien & Gere

6 Final EPA VI Guidance OSWER Publication OSWER TECHNICAL GUIDE FOR ASSESSING AND MITIGATING THE VAPOR INTRUSION PATHWAY FROM SUBSURFACE VAPOR SOURCES TO INDOOR AIR U.S. Environmental Protection Agency Office of Solid Waste and Emergency Response June 2015 FINALLY OUST Publication EPA 510-R Technical Guide For Addressing Petroleum Vapor Intrusion At Leaking Underground Storage Tank Sites U.S. Environmental Protection Agency Office of Underground Storage Tanks June

7 ASTM E Real Estate Transactions Standard Guide for Vapor Encroachment Screening (VES) on Property Involved in Real Estate Transactions A voluntary guide for due diligence investigations of commercial properties ~ Screening process that requires information similar to information generally collected as part of a Phase I ESA. ~ Does not replace state or EPA rules or guidance. ~ Defines a procedure for identifying whether a VEC exists, likely exists, cannot be ruled out, or can be ruled out. ASTM E , Standard Guide for Vapor Encroachment Screening on Property Involved in Real Estate Transactions, ASTM International, West Conshohocken, PA, 2010,

8 ASTM E Tier 1 versus Tier 2 Two levels of screening: ~ Tier 1: focuses on the research of records from a known or suspected contaminated site in an area of concern (prior investigations, government records, etc.) ~ Tier 2: focuses on actual known spills or plumes from any contaminated sites in an area of concern and their proximity (critical distance) to the property Could involve sampling to identify if vapors have encroached on the property ASTM E , Standard Guide for Vapor Encroachment Screening on Property Involved in Real Estate Transactions, ASTM International, West Conshohocken, PA, 2010,

9 Page 15, Table 1-2 Note important updates to Indoor Air Testing 9

10 Key Recommendation Highlights Limit analyses to chemicals of concern Section 6.4 Assess the VI pathway using multiple lines of evidence Sections 6.3, 7.1 & 7.2 Generally support the decision to collect indoor air data Section & Consider collecting multiple rounds of indoor air samples Section 7.4 Document objectives and methods in a VI work plan Section

The Conceptual Site Model (CSM) A CSM integrates all lines of site-specific evidence into a three dimensional conceptualization of site conditions A picture and narrative of the site and it s

11 The Conceptual Site Model (CSM) A CSM integrates all lines of site-specific evidence into a three dimensional conceptualization of site conditions A picture and narrative of the site and it s contamination How it got there Is it migrating or degrading It s distribution across the site Who might be exposed and at what levels Section The CSM will help guide the DQOs Considerations: Site conditions and historical data Screening levels being applied Sampling protocols being used Compounds of concern Anticipated concentrations Rick Ehrhart, RCRA Corrective Action, EPA Region 6, ehrhart.richard@epa.gov Involve the lab early and accept comment s on the achievability of DQOs.

Sources of Variability http://www.itrcweb.org/gd_vi.

Barometric pressure Surface cover Preferential pathways Soil moisture &

12 Sources of Variability ITRC 2007 Sources of Potential Variability in Measured Data Barometric pressure Surface cover Preferential pathways Soil moisture & permeability Building depressurization Seasonal effects: Advection Biodegradation Background air 12

13 Multiple Lines of Evidence

Vapor Intrusion Concurrent Sampling Wind Effect Stack

Indoor sources: carpet, dry cleaned goods, air

Vapors In/Out Breathing Zone HVAC Vapor Transport:

gradient Preferential Pathways Vapors in Vapors out!

14 Vapor Intrusion Concurrent Sampling Wind Effect Stack Effect Barometric Pressure Changes Ambient Background Indoor sources: carpet, dry cleaned goods, air fresheners, glues, paint, solvents, paints, smoke, heating oil, K2. Other sources: Vapor Intrusion, Ambient Air Intrusion Vapors In/Out Breathing Zone HVAC Vapor Transport: Concentration gradient -Pressure gradient Temperature gradient Preferential Pathways Vapors in Vapors out! Geologic heterogeneity Soil Moisture content Sub-Slab Vadose Zone Water Table Contaminated Groundwater

15 EPA Indoor Air Screening Levels

16 Indoor Air Sampling Pros Actual indoor air concentration, no modeling, no attenuation factors Relatively quick, no drilling or heavy equipment Less spatial variability than soil gas Cons Working with the Homeowner requires time and effort Access agreements, factsheets, meetings Requires removal of potential interior or lifestyle sources Contribution from unknown indoor sources and ambient air Section A potential shortcoming of indoor air is background Per EPA: Collect indoor samples and compare with controls Sub slab, ambient, lines of sight and building specific evidence Modified from: Rick Ehrhart, RCRA Corrective Action, EPA Region 6

Background Contamination Common Household Contaminants Consumer Activities Household Products Building Materials Outdoor Air Source: NJDEP Section 6.3.

17 Background Contamination Common Household Contaminants Consumer Activities Household Products Building Materials Outdoor Air Source: NJDEP Section Identify & Evaluate Contributions from Indoor & Ambient Sources Acetone Benzene Bromomethane 2-Butanone (MEK) Chlorobenzene Chloroethane Chloroform Cyclohexane 1,4-Dichlorobenzene Dichlorodifluoromethane 1,1-Dichloroethane 1,3-Dichloropropene Ethylbenzene Formaldehyde n-heptane n- Hexane Methylene chloride Methyl isobutyl ketone Methyl tert butyl ether Styrene 1,1,2,2- Tetrachloroethane Tetrachloroethene (PCE) Toluene 1,1,1-Trichloroethane Trichloroethene (TCE) Xylenes, total

18 Sub Slab Sampling Pros Can be used to resolve indoor sources vs. a VI source Can be used to assess if the VI migration route is complete Can be used to assess the potential for VI risk Cons Method is intrusive Requires access agreement and entry into buildings. Substantial spatial variability under the slab Per EPA: Collect multiple samples per building to address spatial variability and multiple rounds to address temporal variability. Section There may be substantial spatial variability in subslab soil gas

Soil Gas Sampling Pros Near source, it may provide an estimate of source vapor concentration Can be performed without entering the structure Cons Significant lateral and vertical spatial variability

19 Soil Gas Sampling Pros Near source, it may provide an estimate of source vapor concentration Can be performed without entering the structure Cons Significant lateral and vertical spatial variability May not be representative of vapor concentrations under buildings Section individual exterior soil gas samples cannot generally be expected to accurately estimate subslab or indoor air concentrations Per EPA: Several rounds of sampling are generally recommended, particularly Modified from: Rick Ehrhart, RCRA Corrective Action, EPA Region 6

In Field Leak Detection Leak check procedure /Tracer Gases: Use a portable monitoring device to analyze prior to sampling If high concentrations (> 10%) are observed, the probe seal should be

20 In Field Leak Detection Leak check procedure /Tracer Gases: Use a portable monitoring device to analyze prior to sampling If high concentrations (> 10%) are observed, the probe seal should be enhanced to reduce the infiltration of ambient air Companies such as: Section a reliable seal of the annulus between the probe and the probe housing and leak testing for the seal are generally recommended

21 Field Leak Check Testing Quantitative proof of sample integrity in the field Concurrent in Indoor Air Sample (elevated) Helium cylinder Probe Installation Enclosure Pump for purging Sub-Slab sample Canister Sub-Slab Probe Field Helium Meter

22 Shut-in Leak Test 1. Remove brass plug 2. Loosen FC fitting 3. Attached FC to Can 4. Finger tighten 5. ¼ turn with wrench 6. Attach brass plug to FC 7. Tighten with wrench 8. Open and close valve 9. Observe gauge reading 22

23 Field Quality Control Samples Field Duplicates Require the use of a T-fitting or Co-locator

24 Media Selection Determined by reporting limit requirements Summa Canisters: Soil Gas: 1L generally acceptable Ambient & Indoor Air: 6L only Flow Controllers Preset by the laboratory for 5 minto 24hrs Tedlar Bags: For gases and high levels of detection

25 Sampling Equipment 6 liter canister with 200 ml flow meter 6 liter canister with 24hr flow controller 200 ml flow meter with filter and gauge Flow controller with filter and gauge

Media Certification and Management Canisters are segregated for cleaning Low level (ambient & indoor) Source level (soil gas) Canister Cleaning Evacuated, heated,

26 Media Certification and Management Canisters are segregated for cleaning Low level (ambient & indoor) Source level (soil gas) Canister Cleaning Evacuated, heated, pressurized w/ zero air or nitrogen Certification Batch or individual Leak free overnight leak check test required Flow Controller Certification: Cleaned & Performance checked

27 Canister Certification Timing Certification 48 hr min Leak Check Overnight Inventory Ship out 24 to 72 hrs Certify Field Sampling Clean Lab Analysis Return to lab - 24 hrs to 4 weeks Clean 24hrs 5 days Analysis 24 hrs to 2 weeks

Nylaflow Tips: Minimize length Store properly Initial Vacuum confirm sufficient

28 Tubing & Gauges, Impact to Data? Field Sampling Media Tubing options: Stainless steel < Teflon FEP < Polyethylene < Nylaflow Tips: Minimize length Store properly Initial Vacuum confirm sufficient vacuum is in the canister. Range will be Hg Final Vacuum confirm sufficient sample was collected. Range should generally be 10-0 Hg

preservation required Can be shipped by air with a few caveats ~ Do not overfill Hold time

29 Shipping, Preservation and Holding Times Canisters No preservation required Can be shipped by air with a few caveats Hold time specified in TO-15 is 30 days Tedlar bags No preservation required Can be shipped by air with a few caveats ~ Do not overfill Hold time is 72hrs Section Fourteen days is the most commonly cited hold time for air samples in canisters

Involve Your Laboratory in the Planning Process Compounds of concern & anticipated concentrations Detection limits Type(s) of sampling equipment ~ 1 liter vs 6 liter ~ Batch vs Individual

30 Involve Your Laboratory in the Planning Process Compounds of concern & anticipated concentrations Detection limits Type(s) of sampling equipment ~ 1 liter vs 6 liter ~ Batch vs Individual certification ~ Tubing ~ Flow controllers and settings ~ T-fitting ~ Extra fittings Number of samples Sample types Report type Involve the lab early. Request comments on the conceptual site model (CSM) and achievability of data quality objectives

31 Summary Do not take samples unless you have some idea of what the data is going to tell you - Conceptual Site Model Define your data quality objectives up front, this will determine the appropriate containers, collection procedures and analyses Over communicate with your testing laboratory. Teamwork up front will ensure less discussion when you receive your data Data quality is a function of the whole process: the project set up, the field sampling protocols, and the analytical protocols

32 Thank You for Attending Questions?

33 Vapor Intrusion Contacts TestAmerica Burlington, VT Don Dawicki (direct dial) Ambient Air Product Manager ~ Tom Yoder in Knoxville, TN ~ ~ (direct dial) ~ tom.yoder@testamericainc.com TestAmerica Knoxville, TN TestAmerica Phoenix, AZ Jamie McKinney (direct dial) ~ ~ ~ TO-17 and passive sampling Kylie Emily jamie.mckinney@testamericainc.com ~ kylie.emily@testamericainc.com TestAmerica Sacramento, CA Taryn McKnight (direct dial) taryn.mcknight@testamericainc.com

Ask The Expert Webinar Series Vapor Intrusion Assessments Part Two: Improving Data Quality Using Today s Best Practices for Sample Analysis

Ask The Expert Webinar Series Vapor Intrusion Assessments Part Two: Improving Data Quality Using Today s Best Practices for Sample Analysis Taryn McKnight Client Relations Manager The migration of volatile