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

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What Is The Toxicity of PCE?

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EPA Johnson and Ettinger Model Website Has Been Updated

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Michigan DEQ’s Approach to Vapor Intrusion

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Pennsylvania Vapor Intrusion Draft Guidance

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Proposed Changes to Connecticut Volatilization Criteria

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GRA Vapor Intrusion Symposium

 • 

RCRA National Meeting

 • 

EnviroGroup Boston Office


Featured Links:

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Part 201 of the Michigan Natural Resources and Environmental Protection Act

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Michigan Generic Cleanup Tables

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Michigan Vapor Intrusion Documents
What Is The Toxicity of PCE?
The toxicity of PCE or tetrachloroethylene, a common groundwater and vapor intrusion compound of concern, is the subject of significant controversy. Resultant vapor intrusion “action levels” vary between agencies and will likely vary over time. Click on the following link for a brief overview of the current status of PCE toxicity, particularly as it relates to vapor intrusion.

The toxicity of PCE as it affects vapor intrusion: an overview (July 2003)



EPA Johnson and Ettinger Model Website Has Been Updated
The Johnson and Ettinger models on the EPA Superfund web site have been updated to now incorporate the default values recommended in the OSWER Draft Guidance for Evaluating the Vapor Intrusion for Evaluating the Vapor intrusion to Indoor Air Pathway (November 2002). The default parameters include both building related and soil type related numbers designed to provide a reasonably conservative assessment. Building related parameters include estimates such as air exchange rates, footprint area, perimeter crack width, and crack ratios. Soil related parameters include moisture content for both the unsaturated and capillary transition zones. These models can be found at:

EPA Superfund JEM Link



Michigan DEQ’s Approach to Vapor Intrusion
Michigan’s environmental remediation requirements are derived from Part 201 of the Natural Resources and Environmental Protection Act. The rules implementing this section of the law can be found at the first "featured link" in the left column of this newsletter (or at the bottom, if you are viewing a text version of the newsletter).

Rule 714 explains the basis for the generic criteria for groundwater based on hazardous substance vapors emanating from groundwater to indoor air. Likewise Rule 724 explains the generic cleanup criteria for soil based on volatilization to indoor air. Clicking on the second link in the left column will provide you with three generic cleanup tables.

The Rule 744 table is Table 1 providing the generic groundwater cleanup criteria including volatilization criteria for two land use classes. The Rule 746 table is Table 2 providing the generic soil cleanup criteria for residential and some commercial land uses including the volatilization criteria. The Rule 748 table is Table 3, which provides similar soil cleanup criteria for industrial and other commercial land uses. The Rule 750 table includes the footnotes which help explain the other three tables.

Two key vapor intrusion documents can also be accessed through the third link in the column to the left. Under “Information”, click on the second listing: Part 201/213 Acceptable Indoor Air Concentrations. This will bring you to a seven page table of acceptable air contaminants for both residential and industrial and commercial land uses. Under “Part 201 Operational Memoranda and Guidance” click on: Technical Support Documents for Op Memo # 18. Then click on: Generic Groundwater and Soil Volatilization to Indoor Air Inhalation Criteria. This will bring you to the 1998 Technical Support Document, which explains in detail how the groundwater and soil volatilization criteria were developed. This document is currently being updated and will include guidance for collecting soil gas and indoor air samples as an alternative means (from the generic screening criteria) for assessing the indoor air pathway.

Links for a variety of other state vapor intrusion programs can be found at the following link. New states are added all the time, so check back later if the state you are interested in is not shown.


Links to other state VI programs



Pennsylvania Vapor Intrusion Draft Guidance
The Pennsylvania Department of Environmental Protection is in the final stages of developing detailed vapor intrusion guidance to be incorporated into its Technical Guidance Manual for the Land Recycling Program under the Act 2 legislation. The guidance will be presented to the Cleanup Standards Scientific Advisory Board July 22 for approval and the anticipated effective date is October 26, 2003. The guidance will fit under the statewide health standard of the Land Recycling Program. The guidance includes nine tables of screening numbers for ground water, soil, and indoor air considering aquifers which are both used and not used for drinking water and for residential and commercial/industrial land uses. The tables were calculated using a cancer risk of 10 -5. Evaluation of this pathway is necessary when an inhabited building is located within 100 feet of a source of groundwater plume containing volatile compounds. Although this document is not a regulation it establishes the framework within which DEP will exercise its administrative discretion in the future. The draft guidance can be found at (click on the items under the June 11, 2003 heading):

Pennsylvania draft vapor intrusion guidance



Proposed Changes to Connecticut Volatilization Criteria
In March 2003 Connecticut proposed changes to its volatilization criteria and is accepting comments until June 30, 2003. Connecticut was one of the first states in the country to directly address this pathway of exposure and has had volatilization criteria from at least 1996. The changes include the updated Johnson Ettinger model considering both diffusion and advection, updated target air concentrations based on current toxicity information and background levels, application of the criteria to ground water within 30 feet of the surface (as opposed to 15 feet), less stringent criteria for industrial/commercial land use, and special attention to the potential exposures of children. Background data from several sources has been examined and used to set the target air concentrations for substances where the risk based calculated numbers would have been below background (TCE, PCE, benzene). The target air concentrations for vinyl chloride and 1,1-DCE have been made less restrictive and the target air concentration for TCE has been made more restrictive. The proposed changes can be found at:

Proposed Changes to Connecticut Volatilization Criteria



GRA Vapor Intrusion Symposium
The Groundwater Resources Association (GRA) of California is sponsoring a symposium on Subsurface Vapor Intrusion to Indoor Air on September 30 and October 1, 2003 in San Jose and Long Beach CA, respectively. The one day seminar includes presentations on California's perspective on vapor intrusion issues, collection of field data, predictive modeling, background concentrations, and engineering controls. Speakers include DTSC, EPA, and San Francisco RWQCB experts, as well as Paul Johnson and Robbie Ettinger. Click on the following link for more information.

GRA Subsurface Vapor Intrusion Symposium



RCRA National Meeting
This year's RCRA National Meeting, to be held in Washington D.C. August 12-15, 2003, will feature special sessions on vapor intrusion. Click on the following link for more information.

RCRA National Meeting 2003



EnviroGroup Boston Office
EnviroGroup is pleased to announce the opening of its Boston office as of July 2003. Although EnviroGroup has always provided clients with expert environmental and vapor intrusion services across North America, our Boston office allows us to provide more rapid and cost effective services in the northeast. Click below for more information:

EnviroGroup Limited



 
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