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SOO <br /> San Joaquin County DIRECTOR <br /> PQ N Donna Heran, REHS <br /> �O C� Environmental Health Department ASSISTANT DIRECTOR <br /> 600 East Main Street Laurie Cotulla, REHS <br /> Stockton, California 95202-3029 PROGRAM COORDINATORS <br /> • :• Carl Borgman,REHS <br /> Mike Huggins,REHS,RDI <br /> cq� F Ra`P Website: www.sjgov.org/ehd Margaret Lagorio, REHS <br /> Phone: (209)468-3420 Robert McClellon,REHS <br /> Fax: (209)464-0138 ,teff Carruesco,REHS, RDI <br /> Kasey Foley, REHS <br /> JERRY MOORE <br /> MOORE PETROLEUM JUN 2 5 2007 <br /> 885 PORTOFINO DR <br /> BRENTWOOD CA 94513-6539 <br /> RE: Moore Petroleum Bulk Plant <br /> 5491 F Street <br /> Banta CA 95304 <br /> The San Joaquin County Environmental Health Department (EHD) has received <br /> and reviewed Soil Vapor Survey Workplan (WP) dated 10 May 2007, prepared <br /> by Apex Envirotech, Inc. (AEI) on your behalf. <br /> In WP, AEI proposes to advance 13 soil vapor survey points 'at on- and off-site <br /> locations to collect soil vapor samples for laboratory analysis. AEI proposes to <br /> drive the sampling points to a depth of three feet below surface grade (bsg) and <br /> to collect the samples into Tedlar bags after purging 3 casing volumes of soil gas <br /> and monitoring the pumped soil gas with a PID to select the time of maximum <br /> contaminant concentrations. The soil gas samples are proposed to be collected <br /> utilizing the "whole-air active approach", which the EHD is not familiar with. <br /> The EHD cannot approve the work plan as proposed for the following reasons: <br /> • Department of Toxic Substances Control (DTSC) and other agencies <br /> recommend a minimum sampling depth of 5 feet below surface grade <br /> (bsg) to minimize the effects of barometric pumping; <br /> • A detailed description of the probes, means of emplacement, air pump <br /> and pumping rate was not provided; and <br /> • The analytical regimen for the soil gas samples should include 1,2- <br /> dichloroethane and ethylenedibromide. <br /> The DTSC guidance document, Interim Final Guidance for the Evaluation and <br /> Mitigation of Subsurface Vapor Intrusion to Indoor Air, 15 December 2004, states <br /> that purging and sampling flow rates should be less than 200 milliliters per <br /> minute. <br /> Submit a revised work plan addressing the points noted above to the EHD by 03 <br /> September 2007. The DTSC guidance document or other authoritative guidance <br /> document should be referred to in the revised work plan. As these are guidance <br />