[CPEO-BIF] Region 9 Vapor Intrusion Guidelines for South (San Francisco) Bay Superfund sites

[Lenny Siegel <lsiegel@cpeo.org>]

On December 3, U.S. EPA sent a letter to the San Francisco Bay Regional Water Quality Control Board, "EPA Region 9 Guidelines and Supplemental Information Needed for Vapor Intrusion Evaluations at the South Bay National Priorities List (NPL) Sites." The letter puts into writing many of the policies and practices developed by Region 9 at the Moffett Field-MEW Regional TCE plume in Mountain View. The Water Board is the lead agency at several other NPL sites in the area with volatile organic compounds in groundwater. EPA recommends that the document be incorporated into "existing and future Vapor Intrusion Evaluation Work Plans" at those sites.

Among its recommendations, the letter calls for multiple sampling events at residential properties and ventilation-on and ventilation-off sampling at commercial properties. It provides groundwater screening levels for trichloroethylene (TCE), and it establishes action levels based upon the short-term exposure of women of child-bearing age to TCE in indoor air. It also re-affirms the applicability of exposure standards based upon California's tetrachloroethylene (PCE) inhalation toxicity assessment.

The letter may be downloaded from
http://yosemite.epa.gov/r9/sfund/r9sfdocw.nsf/3dc283e6c5d6056f88257426007417a2/7a625c26cbf2561e88257c38007610c8!OpenDocument

You may need to copy and paste the link.

Lenny


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Lenny Siegel
Executive Director, Center for Public Environmental Oversight
a project of the Pacific Studies Center
278-A Hope Street
Mountain View, CA 94041
Voice: 650-961-8918 or 650-969-1545
Fax: 650-961-8918
LSiegel@cpeo.org
http://www.cpeo.org




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