Laserfiche WebLink
Weldon Church Property Page 2 <br /> 104 West Beverly Place September 1, 2011 <br /> Tracy, California 95376 <br /> This AGE proposes in place of resubmitting the recalculated human health risk by entering <br /> the highest soil gas concentrations into the Johnson and Ettinger Model as directed by the <br /> EHD by letter dated 14 June 2011. AGE supported this proposal with the following <br /> statements: <br /> • Air samples collected from crawl spaces are considered by the Department of Toxic <br /> Substances Control (DTSC), California Environmental Protection Agency, to be <br /> equivalent to indoor air samples. ["The indoor air quality is assumed to be equal to <br /> the crawl space air quality for evaluation purposes" - reference Interim Final — <br /> Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor <br /> Air, dated 15 December 2004 (revised 07 February 2005) published by the DTSC] <br /> • The Johnson and Ettinger Model is intended for structures with slab foundations. <br /> (The residency at this site does not have a slab foundation.) <br /> • Unlike the Johnson and Ettinger Model, the proposed RISC V software for <br /> calculating the carcinogenic risk and hazard quotient does not use attenuation <br /> factors. <br /> The EHD approves an air sample field blank and the collection of duplicate air samples from <br /> the crawl space beneath the dwelling at this site. Analyze the air samples for TPH-g and <br /> benzene, toluene, ethylbenzene and total xylenes (BTEX), omitting the analyses for methyl <br /> tertiary-butyl ether (MTBE), ethyl tertiary-butyl ether (ETBE), di-isopropyl ether (DIPS), <br /> tertiary-amyl methyl ether (TAME) and tertiary-butyl alcohol (TBA) since these analytes have <br /> not been detected in any of the soil gas or air samples collected to date. <br /> The EHD will not comment on whether an indoor sample or samples should be collected <br /> until the EHD has received the report of findings from this current investigation. Notify the <br /> EHD at least a week prior to the scheduled date for collecting the crawl space samples and <br /> submit the report of findings to the EHD by 30 November 2011. <br /> If you have any questions concerning this letter, please contact Vicki McCartney at (209) <br /> 468-9852, or by email at vmccartney@sjcehd.com. <br /> Sincerely, <br /> J <br /> �,,�- ee <br /> Victoria L. McCartney, REHS Nuel C., Henderson, Jr., PG <br /> Senior Registered Environmental Health Specialist Engineering Geologist <br /> c: Mr. Brian Millman, Advanced GeoEnviron mental, Inc. 837 Shaw Road, Stockton, <br /> California 95215 <br /> Mr. James L.L. Barton, PG, California Regional Water Quality Control Board Central <br /> Valley Region, 11020 Sun Center Drive, Suite 200, Rancho Cordova, California 95670 <br /> Frank and Bette A. Grande Family LP, Post Office Box 1076, Tracy, California 95378 <br />