SITE INFORMATION AND CORRESPONDENCE 2011-2015

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San Joaquin County .� Environmental Health Department DIRECTOR �'� a. �-%� 600 East Main Street Donna Heran, RENS 2 U): VIII* { Stockton, California 95202-3029 PROGRAM COORDINATORS Robert McClellon,REHS r. Jeff Carruesco, REHS,RDI A"P Website: www.sjgov.org/ehd Kasey Foley, REHS i F o R Linda Turkatte,REHS Phone: (209) 468-3420 Fax: (209) 464-0138 April 1, 2011 Mr. Weldon Church 1958 Yosemite Road Berkeley, California 94707 Subject: Weldon Church Property 104 West Beverly Place Tracy, California 95376 Dear Mr. Church: The San Joaquin County Environmental Health Department (EHD) has reviewed Crawl Space Air Investigation Work Plan (work plan), dated 28 February 2011, submitted by your consulting firm, Advanced GeoEnviron mental, Inc. (AGE) on your behalf for the above- referenced site. By letter dated 14 January 2011, the EHD had directed the submittal of a work plan to address collecting air samples in the crawl space beneath the residential dwelling at your site. AGE proposes to collect two ambient air samples south of the home and one air sample in the crawl space beneath the home at 104 West Beverly Place in Tracy, California, as illustrated in Figure 2 of the work plan. It appears that AGE proposes to access the crawl space on the south side of the dwelling and that the six-liter Summa canister used to collect the air sample beneath the home will be set outside the crawl space area; tubing attached to the Summa canister will be inserted horizontally along the floor of the crawl space to a distance approximately halfway between the front and back of the home's foundation. Since the opening to the crawl space is adequate to insert the Summa canister within the crawl space, the EHD directs that the Summa canister be relocated a couple of feet within the crawl space and the doors leading to the crawl space be closed during the sample collection. This will provide greater assurance that the air entering the Summa canister is indeed from the crawl space, and will prevent the Summa canister from being exposed to the sun. AGE proposes to place the Summa canisters approximately 10 to 15 feet from the residence and 2 to 3 feet above the ground surface to collect the ambient air samples. It appears that one of the two Summa canisters used to collect ambient air is adjacent to the fence on the west side of the property. Since the Interstate Technology & Regulatory Council's Technical and Regulatory Guidance - Vapor Intrusion Pathway: A Practical Guideline (Guidance), dated January 2007, states that "outdoor air samples should be collected from a representative upwind location, away from wind obstructions such as trees and buildings", the EHD suggests that this Summa canister be relocated at least 5 to 10 feet away from the fence. The Guidance also recommends, and the EHD concurs, that you collect meteorological data during the air sampling event. Although crawl space air