BEYOND THE GUIDANCE. The making of the ITRC PVI Guidance Document. Catherine Regan, ERM Boston Matt Lahvis, Shell Houston

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1 BEYOND THE GUIDANCE The making of the ITRC PVI Guidance Document Catherine Regan, ERM Boston Matt Lahvis, Shell Houston

2 Introduction 2

3 Motivation for Guidance Document VI Pathway is on the national scene, but PVI specifics are mostly ignored $ $ $ $ $ $ $ $ Lack of guidance and training to support confident decision making Site Investigation 3 Vapor Control & Management

4 Motivation for Guidance Document Experience with chlorinated compound vapor intrusion (CVI) heightens concern for PVI Limited resources without effective prioritization process to focus on sites with greatest potential for PVI Financial impacts (e.g., delays in construction or property transactions) Potential adverse health effects of building occupants if vapors at sufficiently high concentrations Source: ITRC PVI Internet Based Training, January

importance of biodegradation in PVI evaluations Applicable to a variety of

5 The Need To create a document that: Provides a strategy for screening, investigating and managing potential PVI sites Explains and incorporates the importance of biodegradation in PVI evaluations Applicable to a variety of petroleum site types (more than just your typical gas station) Scientifically based on the latest research 5

6 Up for the Challenge Interstate Technology and Regulatory Council (ITRC) ( Host Organization - ECOS State regulators All 50 states, PR, DC Federal partners ITRC Industry Affiliates Program Academia Community stakeholders DOE DOD EPA

7 Up for the Challenge Team Composition 47 state regulators 75 consultants 13 federal representatives 35 vendors and industry reps 6 community stakeholders 5 academia Industry Stakeholder Academia States Federal Consultants

8 The Group Process Our Goal: Make a Positive Impact on Target Users Build skills and knowledge Support the transfer of new skills and knowledge to create improved on-the-job performance Empower confident decision-making User Target

Databases Summary of Various Empirical Database Results Sampling

Intrusion Screening at Petroleum Hydrocarbon Sites Microbiology

Policy Review of OUST PVI Draft Guidance Perspectives on PVI from

9 The Group Process What was important? General Principles of PVI Bioattenuation of Hydrocarbons PVI Databases Summary of Various Empirical Database Results Sampling and Analytical Issues Site Exclusion Criteria Investigations Vapor Intrusion Screening at Petroleum Hydrocarbon Sites Microbiology Primer Summary of California Low-Threat Petroleum UST Case Closure Policy Review of OUST PVI Draft Guidance Perspectives on PVI from States and DoD Perspectives on PVI from Community Stakeholder and Tribal Representative ITRC, 2014 ITRC,

10 Important Topics 10 Investigation and BioVapor PVI vs CVI EPA Vertical Analysis Biodegradation and Screening Other Preferential Toolbox Databases Mitigation CSMPathways for PVI

Site screening using vertical screening distance PVI Site

11 What was Created ITRC s PVI Assessment Strategy Figure 1-2. PVI strategy flowchart Community Engagement Strategy includes: Site screening using vertical screening distance PVI Site investigation Vapor Control and Site Management ITRC PVI, 2014: Figure 1-2

12 Consensus Building Need to Know Must Know Focus on the target User Decides what s need to know and what s nice to know Providing opportunity for debate on topics Need to Know Nice to Know McArdle, 1993

Hot Topics Clean or Non-Source Soil ISSUE: application of screening distances assumes clean or non-source soil between source and building foundation criteria: CLEAN OR

13 Hot Topics Clean or Non-Source Soil ISSUE: application of screening distances assumes clean or non-source soil between source and building foundation criteria: CLEAN OR NON- SOURCE SOIL Vadose Zone O 2 soil-gas > 1-5% vol/vol TPH soil < mg/kg PID < ppmv no odors /staining terminology HYDROCARBON SOURCE Saturated Zone Water Table

14 Criterion Oxygen (O 2 ) < 1-5% vol/vol CONCERNS: O 2 soil-gas sampling defeats purpose of site screening applicable O 2 soil-gas concentration (e.g., lower threshold for aerobic biodegradation: O 2 soil gas > 1-5% vol/vol) aerobic threshold No PVI Risk O 2 soil-gas measurements not meaningfully factored into derivation of screening distances RESULT: O 2 soil-gas measurements not necessary for site screening LNAPL presence/absence is key factor provided 1 o and 2 o sources identified O 2 soil-gas measurements can help support PVI CSM during further site assessment RELATIVE DISTANCE ABOVE SOURCE 1 0 AEROBIC RBSL x Biodegradation Interface ANAEROBIC 0 1 RELATIVE SOIL-GAS CONCENTRATION >5%O 2 1-5% O 2

15 LNAPL Indicator Criteria Indicator benzene: > 1-5 mg/l TPH (gasoline) : > 30 mg/l BTEX: > 20 mg/l current or historical presence of LNAPL (including sheens) current or historical presence of LNAPL (staining) benzene > 10 mg/kg TPH (gasoline) > mg/kg ultraviolet fluorescence (UV) or laser induced fluorescence (LIF) fluorescence response in LNAPL range PID or FID readings > 500 ppm Groundwater Soil Comments no specific hydrocarbon concentration in groundwater that defines LNAPL because: - varying product types - degrees of weathering use of TPH soil concentrations as LNAPL indicators should be exercised with caution: - can be affected by the presence of soil organic matter - TPH soil concentrations are not well correlated with TPH or O 2 soil gas concentrations Location relative to UST system (e.g., tank, dispenser, pipework) or AST adjacent (e.g., < 20 feet) from a known or suspected LNAPL release or petroleum UST/AST equipment probability of encountering LNAPL increases closer to release location

16 Criterion - TPH Soil Concentration < 250 mg/kg CONCERNS: TPH identified as a potential PVI risk driver (Brewer et al., 2013) TPH is a poor predictor of PVI risk (drive unnecessary sampling and analysis) non-petroleum sources From Golder Associates (2008) soil concs over predict soil-gas concs (Golder Associates, 2008) VOC loss biodegradation TPH soil concentrations not well correlated with TPH or O 2 soil-gas concentrations (Lahvis and Hers, 2013) F1 = C 6 C 10 hydrocarbons

$screening distances for TPH fractions < 3 ft * -------- * derived using MaDEP soilgas screening levels for a relatively small population of soil-gas data (~ 50 data points) From Lahvis and Hers$

17 Criterion - TPH Soil Concentration < 250 mg/kg TPH risk varies widely depending on product type TPH soil concentrations not meaningfully applied in derivation of screening distances vertical screening distances for TPH fractions < 3 ft * * derived using MaDEP soilgas screening levels for a relatively small population of soil-gas data (~ 50 data points) From Lahvis and Hers (2013)

18 Criterion - TPH Soil Concentration < 250 mg/kg RESULT: focus placed on assessment of individual compounds rather than TPH concentrations in soil and groundwater can be used to help identify: LNAPL sources type of LNAPL present (i.e., gasoline vs. diesel)

19 Did It All Work Out?? Reviewed by State and Federal Agencies ITRC PVI Guidance released as a Web-based document in October 2014 Internet based training started January

20 What s Next? 2-Day Classroom Training PVI 20

21 Questions. Catherine Regan ERM (617) Matt Lahvis Shell (281)

Screening Distances for Petroleum Vapor Intrusion Risk Assessment

Screening Distances for Petroleum Vapor Intrusion Risk Assessment 23nd Annual International Conference on Soil, Water, Energy, and Air and AEHS Foundation Annual Meeting San Diego, California March 18-21,