Updated Massachusetts Indoor Air Quality Standards and Their Effects on a Home Heating Oil Release
Rick Stromberg, LFR Inc., Braintree, MA
Steven T. Gaito, LFR Inc., Braintree, MA
Caitlin Bell, LFR Inc., Braintree, MA

Residential Indoor Air Comparative Study Near DoD Facility: Canisters v. Sorbent Tubes v. Passive Diffusion Samplers
Joseph E. Odencrantz, Ph.D, Beacon Environmental Services, Newport Beach,CA
Harry O`Neill, Beacon Environmental Services, Bel Air, MD
Shirley J. Steinmacher, MWH Americas, Salt Lake City, UT     
Jarrod D. Case, 75 CEG/CEVOR, Hill Air Force Base, UT
Paul C. Johnson, Ph.D., Arizona State University, Tempe, AZ

Vapor Intrusion Pathway for a Commercial Facility at a Former Manufacturing Facility – Not the Typical Regulatory Conceptual Model
Michael J. Murphy, MACTEC Engineering & Consulting, Inc., Wakefield , MA
Phillip J. Muller, MACTEC Engineering & Consulting, Inc., Wakefield , MA
David E. Heislein, MACTEC Engineering & Consulting, Inc., Wakefield , MA
Rod R. Rustad, MACTEC Engineering & Consulting, Inc., Portland , ME
Greg Rotondi, Pine & Swallow Associates, Groton , MA 01450

An Overview of Current Vapor Sampling and Modeling Techniques into Indoor and Outdoor Air
Amanda Lee, URS Australia Pty Ltd, Level 3, 116 Miller St, North Sydney, NSW 2037, Australia, Tel: +61 2 89255614, Fax: +61 2 89255555, Email: Amanda_Lee@urscorp.com
Dr Martin Howell, URS Australia Pty Ltd, Level 3, 116 Miller St, North Sydney, NSW 2037, Australia, Tel: +61 2 89255767, Fax: +61 2 89255555, Email: Martin_Howell@urscorp.com
Jackie Wright, URS Australia Pty Ltd, Level 3, 116 Miller St, North Sydney, NSW, 2037, Australia, Tel: +61 2 89255736, Fax: +61 2 89255555, Email: Jackie_Wright@urscorp.com
Stephen Bowly, URS Australia Pty Ltd, Level 3, 116 Miller St, North Sydney, NSW 2037, Australia, Tel: +61 2 89255573, Fax: +61 2 89255555, Email: Stephen_Bowly@urscorp.com

Currently there are a number of options used to estimate indoor and outdoor air concentrations from contaminated soil and groundwater.  The commonly used vapor migration and intrusion models simplify a highly complex issue and usually, but not always, overestimate concentrations within the breathing zone.  Hence such models are commonly used as screening tools with generally wide acceptance of regulators.  However, the limitations of such models are becoming more widely understood and hence the broad use of these models in characterizing inhalation exposures on all sites is questionable.  Hence the use of alternate approaches to traditional methods needs to be considered for many sites. 

Alternate techniques being applied in Australia include sampling and analysis of: soil gas (at varying depths); vapor emitted from the surface; and indoor/ambient air (i.e. breathing zone).  This paper describes the advantages and disadvantages of these techniques associated with sampling and analysis, errors and variability due to changing ambient conditions and background contaminant sources, as well as varying reliance on modeling.  Australian case studies covering a wide range of contaminants are used to support the discussion. 

Key features of the three broad techniques are:

Soil gas – can provide information on vapor profiles beneath buildings, pavements or open areas thus providing a direct measure of vapor phase concentrations in the soils beneath an exposure area as well as information on attenuation not addressed by models.  Sampling can be undertaken from permanent or temporary probes using active and passive techniques.  Consideration of further attenuation into buildings (using default attenuation factors), or use of appropriate vapor models are required to estimate the migration of measured soil gas to outdoor air or into buildings.

Surface emissions – can provide a direct measurement of emissions from the surface (open ground, grass or concrete).  As this method provides the emission rate from the surface it does not require the modeling of vapor migration in the subsurface, rather modeling of measured emissions to the breathing zone outdoors on in a building is required.  Measurements can be time consuming and labor intensive and influenced by the conditions of the surface.  In addition, the technique may not be appropriate for some volatile chemicals and sites particularly where the movement of oxygen into the subsurface is of significance to the behavior of the volatiles targeted. 

Indoor/Ambient air – can provide direct estimates of breathing zone concentrations with no vapor migration and intrusion modeling required.  However, indoor/ambient air sampling will detect all sources of contaminants which may be problematic for common indoor and urban/industrial contaminants.  Concentrations may be subject to large variations as a consequence of changing meteorological and building conditions (e.g. open or closed doors and windows) 

The selection and use of sampling techniques, as well as any vapor models used, should be based on the site-specific conceptual site model.  The collection and use of data and models in conjunction with the conceptual model should assist in ensuring the most appropriate data is collected to characterize inhalation exposures on the site. This approach can, and has, provided a powerful tool for more accurately assessing and managing risks to human health where vapor issues are present.

Updated Massachusetts Indoor Air Quality Standards and Their Effects on a Home Heating Oil Release
Rick Stromberg, LFR Inc., 194 Forbes Road, Braintree, MA 02184, USA, Tel: 781-356-7300, Fax: 781-356-2211, Email:  rick.stromberg@lfr.com
Steven T. Gaito, LFR Inc., 194 Forbes Road, Braintree, MA 02184, USA, Tel: 781-356-7300, Fax: 781-356-2211, Email: steven.gaito@lfr.com
Caitlin Bell, 194 Forbes Road, Braintree, MA 02184, USA, Tel: 781-356-7300, Fax: 781-356-2211, Email: caitlin.bell@lfr.com

The Massachusetts Department of Environmental Protection (MassDEP) Indoor Air Working Group updated residential background indoor air standards in January 2008, which pose changes to indoor air quality evaluations due to reductions in concentrations for many compounds. It includes modified “Upper Percentile Values” (UPVs), used to determine whether indoor air concentrations at a release site are consistent with background concentrations.  

LFR investigated and remediated a sudden heating oil release below a concrete slab of a residence in Massachusetts . Indoor air sampling results taken at the time of release were indicative of a heating oil source; post-remedial sampling was considered consistent with previously published background conditions resulting from a non-heating oil source (such as gasoline from in-building storage of automobiles). LFR was poised to close the case; however, comparison to the new UPVs revealed exceedances. For example, m+p-xylenes were detected at 18.9 µg/m³ and benzene was detected at 5.94-7.44 µg/m³. These concentration were within previous background concentrations and indoor air background values, but above the new UPVs of 9.5 µg/m³ and 3.3 µg/m³, respectively.  

Exceedances of these compounds triggered the need for an evaluation of multiple lines of evidence to show that concentrations above the UPVs were not due to the heating oil release. An extensive indoor air quality assessment was conducted including sample collection in multiple areas of the residence, removal of potential interferences (e.g., lawnmower, automobiles, fuel cans) prior to sampling, and a detailed survey of the presence of potential household contributors (e.g., moth balls, paint, home heating source). Using the data collected to identify multiple lines of evidence, LFR demonstrated that the exceedances of UPVs were not due to the heating oil release, but potentially generated from the presence of two heating oil tanks with an oil burner, mothballs, and/or a previous unreported motor oil release.

Residential Indoor Air Comparative Study Near DoD Facility: Canisters v. Sorbent Tubes v. Passive Diffusion Samplers
Joseph E. Odencrantz, Ph.D, Beacon Environmental Services, 2121 Yacht Yankee, Newport Beach, CA 92660, Tel: 949-644-8602, Email: joe.odencrantz@beacon-usa.com
Harry O`Neill, Beacon Environmental Services, 323 Williams Street, Suite D, Bel Air, MD, Tel: 410-838-8780, Email: harry.oneill@beacon-usa.com
Shirley J. Steinmacher, MWH Americas , 10619 So. Jordan Gateway, Suite 100 , Salt Lake City , UT , 84085 , Tel: 801-617-3200, Email: shirley.j.steinmacher@mwhglobal.com          
Jarrod D. Case, 75 CEG/CEVOR, 7274 Wardleigh Road, Bldg. 5, Hill Air Force Base, UT 84056, Tel: 801-777-3943, Email: jarrod.case@hill.af.mil
Paul C. Johnson, Ph.D., Brickyard BY640, 699 S. Mill Avenue, Arizona State University, Tempe , AZ 85281 , Tel: 480-965-9115, Email: PAUL.C.JOHNSON@asu.edu

Sampling indoor air for potential vapor intrusion impacts using current standard 24-hour sample collection methods may not adequately account for temporal variability and detect contamination best represented by long-term sampling periods.  Mr. Henry Schuver of the U.S. EPA OSW stated at the September 2007 A&WMA vapor intrusion conference that EPA may consider recommending longer-term sampling to achieve more accurate time-weighted-average detections.

Investigations at Hill AFB , Utah , have evaluated vapor-intrusion-to-indoor-air impacts originating from groundwater plumes contaminated with volatile organic compounds (predominantly trichloroethene [TCE]) emanating from the Base and migrating beneath adjacent residential communities. To date, over 4,500 24-hour indoor air samples have been collected in residences. In November 2007, indoor air at four residences was sampled to measure TCE concentrations over short- and long-duration intervals.  A carefully designed investigation was conducted consisting of triplicate samplers for three different investigatory methods: dedicated 6-liter Summa canisters (EPA Method TO-15), pump/sorbent tubes (EPA Method TO-17), and passive diffusion samplers (MDHS 80).  The first two methods collected samples simultaneously for a 24-hour period, and the passive diffusion method collected samples for two weeks.    The testing began November 12, 2007, and the passive diffusion samplers (PDS) were completed on November 26, 2007.

Data collected using Methods TO-15 (canisters) and TO-17 (tubes) provided reliable short-duration TCE concentrations that agree with prior 24-hour sampling events in each of the residences and the PDS time-weighted measurements tracked very closely to the TO-17 results.  The measured TCE concentrations are consistent with previous results with as much as 28.0 ug/m3 measured.  The PDS results are consistently lower than both the TO-15&17 concentrations and the effects of time-weighting of the samplers are more evident at increasing concentrations. The effects of time-weighting the sampling process over a two week period tends to dampen out the peaks by lowering the average concentration.  The TO-17 results more closely track the PDS concentrations with a range of 3.5 to 30% lower concentrations for the two-week versus 24-hour sampling periods, respectively.

Vapor Intrusion Pathway for a Commercial Facility at a Former Manufacturing Facility – Not the Typical Regulatory Conceptual Model
Michael J. Murphy, MACTEC Engineering & Consulting, Inc., 107 Audubon Road , Wakefield , MA 01880 , Tel: 781-245-6606, Fax: 781-246-5060, Email: mjmurphy@mactec.com
Phillip J. Muller, MACTEC Engineering & Consulting, Inc., 107 Audubon Road , Wakefield , MA 01880 , Tel: 781-245-6606, Fax: 781-246-5060, Email: pjmuller@mactec.com
David E. Heislein, MACTEC Engineering & Consulting, Inc., 107 Audubon Road , Wakefield , MA 01880 , Tel: 781-245-6606, Fax: 781-246-5060, Email: deheislein@mactec.com
Rod R. Rustad, MACTEC Engineering & Consulting, Inc., 511 Congress Street , Portland , ME , 04112 -7050, Tel: 207-775-5401, Fax: 207-772-4762, Email: rrrustad@mactec.com
Greg Rotondi, Pine & Swallow Associates, 867 Boston Road , Groton , MA 01450 , Tel: 978-448-9511, Fax: 978-448-6645, Email: grotondi@pineandswallow.com 

A step-wise vapor intrusion investigation of a commercial facility in Rhode Island was conducted in response to low levels of chlorinated volatile organic compounds (VOCs) in up-gradient groundwater.  This investigation highlights the importance of site-specific investigations and the differences between actual site conditions and the typical vapor intrusion conceptual models that have been incorporated into many regulatory programs and guidance.  A sub-slab soil vapor survey was conducted within the building complex and along its exterior perimeter to evaluate potential vapor intrusion.  Based on the soil vapor survey, indoor and outdoor air sampling and analysis was conducted.  Average indoor air concentrations of tetrachloroethene and trichloroethene were at or above target industrial/commercial indoor air screening criteria.  Using direct push technology and a mobile laboratory, a more comprehensive soil vapor investigation was conducted to delineate VOC concentrations horizontally and vertically, identify a source areas within the building footprint, and identify vertical concentration gradients in the subsurface.  Contamination within the groundwater and possibly, within the vadose zone soils, was identified as the likely source for the observed VOCs in soil vapors and indoor air.  Sampling and analysis of groundwater monitoring wells within the building in the soil vapor source area beneath the building confirmed a groundwater source.  The relationships among groundwater, soil vapor, and air concentration distributions are not consistent with many regulatory programs and associated guidance. Gradients and attenuation factors in particular for this commercial site vary considerably from a typical regulatory program conceptual model.  The physical characteristics of the site and the building’s configuration and condition impact several components of the vapor intrusion pathway.  The investigation results, along with pre-design vacuum testing results, and additional groundwater investigation will support vapor mitigation and groundwater remedial system design. 

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