vi presentation cmf

Vapor IntrusionThe Invasion From Below

Christina M. Faust, Senior Project Manager, WhitmanMike Adams, Project Scientist, Whitman

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OverviewWhat is Vapor Intrusion (VI)?

Why Should I Care?Causes of VI

Identifying and Investigating the problemFixing the problem

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What is Vapor Intrusion?NJDEP: … migration of volatile chemicals from the subsurface into overlaying buildings through subsurface soils or preferential pathways.USEPA: … migration of hazardous vapors from any subsurface vapor source, such as contaminated soil or ground water, through the soil into an overlying building or structure.

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Key Terms in the VI world• Vapor• VIG or VITG – Vapor Intrusion Guidance/ Vapor Intrusion Technical Guidance• SSSG –Sub-slab Soil Gas• IA – Indoor Air• IEC – Immediate Environmental Concern• OMM – Operations Maintenance and Monitoring• Res v Non-Res• LSRP – Licensed Site Remediation Professional

• RAL – Rapid Action Level• Capillary fringe• Vadose zone• Attenuation factor• Ambient Air• Critical distance• LTM – Long Term Monitoring• VC – Vapor Concern

Enough with the Acronyms!!

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Why Should I Care?• The VI “Pathway”

– Health impacts of contaminants• Regulatory and Legal Implications

– Buying property– Developing land– Deed Notices & CEAs– Legacy concerns

• Getting ahead of a Problem– Prevention– Mitigation

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The Vapor Intrusion PathwayKey Concepts:1. Contaminant Source2. Contaminant Migration3. Contaminant Exposure (Contaminants are Entering the Building )Collectively, these 3 concepts complete theVI Pathway - Without any 1 feature, Vapor Intrusion cannot exist. Other breathing hazards can still exist.

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A Picture Tells a Thousand Words

Source : NJDEP Vapor Intrusion Technical Guidance (2013)

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Source : USEPA OSWER Technical Guidance (2015)

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Is There a Problem?DUE DILIGENCE!

In NJ, this usually means a Phase I/Preliminary Assessment Report.A proper DD assessment will include diligent inquiry into subject and surrounding property conditions that could cause VI. Remember: Due Diligence is only as good as the party conducting the assessment!

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How is VI Investigated?Source (Typically in ground water, but can be soil)

Migration (Frequently Sub-Slab Soil Gas)

Building (Indoor Air)

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Sampling Ground Water• Only concerned with the top 6 feet of water column

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Sample Sub-Slab Soil Gas• Samples generally collected over ~10 minute period, although time may vary• Major Concerns: “Short circuiting” of soil gas with indoor air

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Sample Indoor Air• Samples usually collected over a 24-hour period• Sample at breathing height• Major Concern: Background Sources

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Background SourcesBackground Sources can cause false positives and costly, unnecessary mitigation. Accounting for background sources:

1. Additional Outdoor Air Sample – “Ambient”2. Detailed Chemical Inventory and Building Survey3. Knowledge of building history (D.D.)

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Building/Chemical Inventory

Background Sources

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Source : NJDEP Vapor Intrusion Technical Guidance (2013)

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Data Interpretation

Source : NJDEP Vapor Intrusion Technical Guidance (2013)Suggests

BackgroundSuggests

VI

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Multiple Lines of Evidence• NJDEP is pushing investigators to provide “Multiple Lines of Evidence” supporting the conclusion that VI is (or is not) an issue at a property. • Additional lines of evidence could include• Soil Characteristics•Building Conditions•Contaminant Ratios in Soil Gas vs. Indoor Air…

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Time is of the Essence - Regulatory Impacts• VI must be investigated 150 days from identification of a potential VI issue.• If an Immediate Environmental Concern is identified, interim mitigation is required to commence within 14 days of identification of an issue (i.e. receipt of sample results).• Other regulatory timeframes may also apply

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VI Identified… What next?Mitigation is required

NJDEP considers Active Sub-Slab Depressurization Systems (SSDS) as the best method of VI mitigation.So, what is an Active SSDS?

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Active SSDS• A SSDS depressurizes the sub-slab and prevents the migration of impacted soil gas into the structure.• Very similar to a Radon Mitigation System, but with more diagnostic checks and regulatory requirements

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Active SSDS

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Active SSDS

Warehouse in New Jersey:• 7-Sump/1-Blower System• Mitigation area of approximately 30,000 sq. ft.

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Active SSDSProper SSDS Design is dependent on:

•Building Use•Construction Type•Soil Permeability

Each building requires a tailored approach

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Alternate Mitigation Approaches – Long Term MonitoringLong Term Monitoring can be appropriate and cost effective when soil gas is elevated, but indoor air clean. It is particularly cost effective if there are near term plans for site redevelopment.

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Alternate Mitigation Approaches – Passive SSDS • Similar to an Active SSDS, but there are no powered fans.•Passive SSDS can usually be converted to Active if needed. • Particularly cost effective in new construction where there is an identified potential for VI and construction can include the installation of a sub-slab venting layer.

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Alternate Mitigation Approaches – Passive SSDSNJDEP guidance references the Cupolex system as one such venting layer, however there are many such products

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Alternate Mitigation Approaches There are other mitigation techniques as well:• Building Pressurization• Soil Vapor Extraction systems• Aerated floor systems• Spray on Barriers (in conjunction w/ other approaches)• Sub-Surface Pressurization• Restriction of building accessMitigation approach should be tailored to the building on a case by case basis.

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Case Study: Ironbound, Newark• Ronson Metals Corp. manufactured lighters in Newark from 1950s to 1989• Environmental investigation had been ongoing, but abruptly ceased in the mid-1990s • Ground water was not properly investigated, fell through the cracks •In 2003, the property was redeveloped with residential homes

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Case Study: Ironbound, Newark

Source: http://www.nj.com/essex/index.ssf/2014/04/newark_homes_not_so_sweet_with_toxic_vapors_seeping_inside.html

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Case Study: Ironbound, Newark

Source: http://www.nj.com/essex/index.ssf/2014/04/newark_homes_not_so_sweet_with_toxic_vapors_seeping_inside.html

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Case Study: Ironbound, Newark

Currently site is identified in NJDEP Mapping Software as Deed Restricted, but known ground water contamination is not mapped as investigation is ongoing.

Source: NJDEP GeoWeb

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Case Study: Ironbound, NewarkAs of December 2015:• 59 residences have been sampled for potential VI issues.• 28 Active Sub-Slab Depressurization Systems have been installed.• The investigation of ground water and potential VI issues is ongoing.

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Case Study: Ironbound NewarkLessons: • VI impacts can be “missed” – especially in older cases• Regardless of blame, litigation can be costly• Proper Due Diligence is the Key to Assessing Risk

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In Conclusion• VI is a necessary consideration for building in NJ, residential or commercial• Assessment of VI potential is an important step in calculating purchase/development risk - Professional due diligence by is critical• There are regulatory and legal ramifications to be aware of • If a risk exists, there are solutions – pre and post construction• VI can be a hurdle - it does not have be a deal breakerFinally, VI is not the sole aspect of a site that can affect indoor air quality, as demonstrated by the now famous Kiddie Kollege case…

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Case Study - Kiddie Kollege

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Questions?Christina M. Faust Project Manager, Whitman732-390-5858cfaust@whitmanco.comorMichael AdamsProject Scientist, Whitman732-390-5858madams@whitmanco.com