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EnviroGroup Limited Vapor Intrusion News - February 2003
In This Issue:

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Comments on EPA Subsurface VI Guidance due February 27, 2003

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EPA training seminars on draft Subsurface VI Guidance

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Johnson & Ettinger Model status

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New indoor air testing procedure expected soon

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New subslab vapor testing procedure

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EI Determinations can rely on JE model

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Vapor Intrusion regulation in California

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What's New? DTSC 1/28/03 guidance on soil gas investigations


Featured Links:

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California DTSC

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CalTOX

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SF Bay RWQCB screening levels

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SF Bay RWQCB 12/24/02 Memo on Soil Gas Screening Levels
Comments on EPA Subsurface VI Guidance due February 27, 2003
Comments on the OSWER Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils (Subsurface Vapor Intrusion Guidance), published November 29, 2002 in the federal register (see link below), are due on February 27, 2003. Industry concerns were raised by John Quarles of Morgan, Lewis & Bockius LLP at the EPA seminars on the guidance in San Francisco and Dallas (see next article), including the need to proceed cautiously with this complex issue, encouragement not to intrude on OSHA regulations at industrial facilities, and concerns regarding the availability of resources to deal with this issue. The federal register notice and copies of the draft guidance are available at:

Federal Register notice and draft guidance



EPA training seminars on draft Subsurface VI Guidance
The last EPA training seminar on the draft Subsurface Vapor Intrusion Guidance will be held in Atlanta on February 25-26, 2003. Some additional space was recently made available by moving to a larger room, so it may still be possible to register at the link below. Otherwise, the seminar presentations will be posted on the internet at the same link in April. Dave Folkes of EnviroGroup will be speaking on the effectiveness of vapor intrusion mitigation systems (see our website to download this paper).

Register for EPA training seminar in Atlanta



Johnson & Ettinger Model status
The indoor air and soil vapor screening levels presented in the draft Subsurface Vapor Intrusion Guidance were developed using the Johnson & Ettinger (1991) model. However, the default parameters used for the guidance are different, and more conservative, than the default parameters used in the model currently posted on the EPA Superfund website (see link below). We understand that EPA is in the process of revising the website version of the model to adopt the default values used by the guidance, and that the revised model will be posted soon. See Appendix G, table G-3 of the draft VI guidance for a list of the default values used in the guidance version of the JE model. Contact us if you have any questions about applying the JE model.

EPA Johnson & Ettinger Model



New indoor air testing procedure expected soon
EPA is currently developing a supplement to the TO-15, the standard summa canister analytical method for collecting high quality indoor air samples for VOC analyses, to incorporate the high resolution tuning procedures developed by the Colorado Department of Public Health and Environment (CDPHE). The draft protocol, called TO-15 Supplement, is currently in the EPA clearance process and is expected to be cleared in about 4 to 8 weeks. Meanwhile, the CDPHE procedure may be downloaded at the following website:

CDPHE Guidance for Analysis of Indoor Air Samples



New subslab vapor testing procedure
EPA is currently perfecting a method for sampling subslab vapors utilizing TO-17. Subslab vapor sampling is a key component of site-specific vapor intrusion evaluations under the draft Subsurface Vapor Intrusion Guidance (see first article), and a potential way to avoid the complications of background or indoor sources of VOCs. The new subslab vapor testing method will be based on TO-17. Both TO-17 and TO-15 are U. S. EPA analytical methods for toxic organic compounds in ambient air, included in the "Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air - Second Edition", Office of Research and Development, (EPA/625/R-96/010b). TO-15 collects the sample in specially prepared (SUMMA) canisters and utilizes high resolution gas chromatography/mass spectrometry for analysis. TO-17 utilizes a pump to draw an air sample onto multi sorbent tubes. Thermal desorption is then used to remove the VOCs and send them on to a sample concentrator. The analytical technique is the same as TO-15.

Current TO-17 Method



EI Determinations can rely on JE model
Current Human Exposures Under Control Environmental Indicators (EIs) do not require confirmatory sampling (i.e., indoor air or subslab vapor samples) to determine control, according to the draft EPA Subsurface Vapor Intrusion Guidance (p.38). In other words, site-specific modeling using the Johnson & Ettinger model (see earlier article) will generally be adequate to determine whether the vapor intrusion pathway has been controlled for EI purposes. EPA cautions that indoor air or subslab vapor testing may be required before approval of the final remedy.

Draft EPA Subsurface Vapor Intrusion Guidance document



Vapor Intrusion regulation in California
Each newsletter, we will try to provide information and links on vapor intrusion developments in different states. Not wanting to take the easy way out, we are starting with California. There are two groups of state agencies which oversee hazardous waste/substance cleanups in California:

I. The Department of Toxic Substances Control (DTSC) is an agency of the California Environmental Protection Agency and is the authorized RCRA agency in California (see Featured Links, upper left margin of newsletter). It also operates the State Superfund Program, a Voluntary Cleanup Program, conducts Brownfields reuse related activities, and oversees cleanups at military facilities. DTSC is currently developing a comprehensive indoor air policy and also regulations for indoor air sampling. DTSC does not have generic soil screening numbers. It does have a Preliminary Endangerment Assessment Guidance Manual available at the link below. It also has developed CalTOX, an automated spreadsheet which is a total exposure model for contaminated soils at hazardous waste sites. It addresses indoor chemical vapors transferred from ground water and soils utilizing the Johnson-Ettinger Model. CalTOX can be found under Featured Links in the upper left margin.


II. The State Water Quality Control Board is an agency of the California Environmental Protection Agency. This agency has responsibility for underground and above ground storage tank remediation. There are 9 regional water quality control boards under this state agency. Some of these boards have developed screening numbers for cleanups. The San Francisco Bay Regional Water Quality Control Board, for example, has risk based screening numbers at the Featured Link in the upper left margin. That regional board has also produced a December 24, 2002 a memo titled: "Interim Soil Gas Screening Levels for Evaluation or Potential Indoor-Air Impacts and Request for Comments". It includes draft shallow soil gas screening levels for use in evaluating potential indoor air impacts. This memo can be reached from the Featured Link in the upper left margin. Regional boards operate Spills, Leaks, Investigation and Cleanup (SLIC) Programs to address the effects of unauthorized discharges. The regional boards sometimes delegate UST cleanups to local governments.


DTSC Preliminary Endangerment Assessment Guidance Manual



What's New? DTSC 1/28/03 guidance on soil gas investigations
On January 28, 2003 DTSC released, jointly with the California Regional Water Quality Control Board - Los Angeles Region, a new guidance document "Advisory - Active Soil Gas Investigations". It can be found at the link below. It was developed to ensure that consistent methodologies are used during soil gas investigations.

DTSC 1/28/03 Guidance on Soil Gas Investigations



This newsletter is issued periodically to provide readers with information on new regulatory and technical developments in the rapidly changing field of vapor intrusion. While every effort is made to ensure that the information and links presented in this newsletter are accurate at the time of publication, they are presented for general informational purposes only. Users should independently verify the accuracy and applicability of this information for any specific sites or purposes. Copyright EnviroGroup Limited 2003.

Please contact us if you have any questions about the topics presented in this newsletter, or vapor intrusion in general.
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