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San Joaquin County DIRECTOR <br /> Donna Heran,REHS <br /> ;AWN Environmental Health Department <br /> �o.•."�� .CO ASSISTANT DIRECTOR <br /> GLaurie Cotulla, REHS <br /> 600 East Main Street <br /> 0: (�„illj'II ' X Stockton, California 95202-3029 PROGRAM COORDINATORS <br /> Carl Borgman,REHS <br /> Website: www.s ov.or /ehd Mike Huggins,RENS,RDI <br /> ��FOR �g g Margaret Lagorio,REHS <br /> Phone: (209)468-3420 Robert McClellon,REHS <br /> Fax: (209)464-0138 Jeff Carruesco, REHS, RDI <br /> Kasey Foley,REHS <br /> January 27, 2009 <br /> Eric Hetrick <br /> ConocoPhillips <br /> Risk Management & Remediation <br /> 76 Broadway <br /> Sacramento, CA 95818 <br /> Subject: 76 Service Station No. 5886 SITE CODE: 1176 <br /> 2701 March Lane <br /> Stockton, CA <br /> The San Joaquin County Environmental Health Department (EHD) has reviewed "Work Plan for <br /> Batch Extraction" (Work Plan) dated December 10, 2008, "Status of Off-Site Access <br /> Agreements with Property Owners" dated December 10, 2008, and the "Quarterly Status and <br /> Remediation Summary Report — Fourth Quarter 2008" (Report) dated January 20, 2009, <br /> prepared by Stantec Consulting Corporation (Stantec) for the above subject site and provides <br /> the following comments. <br /> The EHD visited the site on January 23, 2009. The private roadways into the businesses at <br /> 2800 March Lane are narrow and busy during business hours. Also traffic along March Lane is <br /> heavy during business hours. The EHD suggests that any "batch extraction" activities be <br /> performed during non business hours. The EHD requested copies of the correspondence <br /> between ConocoPhillips and the off-site property owners, but was provided "task notes" from <br /> ConocoPhillips staff and a hand written note from the Transamerica property manager, so the <br /> EHD does not know the contents of the access agreement. If the access agreement specifies <br /> that the batch extraction will be performed during non business hours, then Transamerica <br /> property owners/managers may accept the terms. Another idea would be to perform the <br /> groundwater extraction from March Lane instead of private property. <br /> The concentrations of MTBE in the samples from monitoring wells MW9S, MW91 and MW9D <br /> were below 60 micrograms per liter in October 2008. The EHD discussed this site with the <br /> Central Valley Regional Water Quality Control Board (CVRWQCB) on January 14, 2009, and it <br /> was agreed that if Transamerica would not allow the installation of monitoring wells, then <br /> completion of soil borings for the collection of groundwater samples should be proposed to <br /> investigate the down-gradient extent of the MTBE contamination. The EHD recommends they <br /> be placed in the parking lot east of the Placer Title building (property owned by Transamerica) <br /> so that business traffic will not be impeded. In addition, use of a fate and transport model such <br /> as Bioscreen, a freeware USEPA model, should be considered to show how far the MTBE will <br /> migrate and when all areas of the plume of contaminated groundwater will reach the <br /> CVRWQCB water quality goals. <br />