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California gional Water Quality Corol Board : '-°, :ti <br /> Central Valley Region <br /> yo r <br /> Katherine Hart, Chair <br /> Linda S. Adams 11020 Sun Center Drive#200, Rancho Cordova, California 95670-6114 Edmund G. Brown Jr. <br /> Acting Secretary for Phone(916)464-3291 •FAX(916)464-4645 Governor <br /> Environmental Protection http://www.waterboards.ca.gov/centralvalley RECEIVED <br /> Stephanie McKenna U ���� 1 June 2011 <br /> Chevron Environmental Management <br /> 6111 Bollinger Canyon Road, Rm. 3652 eWR0NMENTAI1fAL1" <br /> San Ramon, CA 94583 PERMi,TISEFMCES <br /> DOCUMENT REVIEW FOR COMMINGLED PLUME ACCOUNT CP0057 SITES AT 440 (TEXACO — <br /> SHELL, RB #390268)/441 (ARCO, RB #390657)/508 (CHEVRON, RB #390876) W, CHARTER <br /> WAYAND 1444 S. LINCOLN STREET, (COL UMBO/TOSCANA BAKERY, RB #390825) <br /> STOCKTON, SAN JOAQUIN COUNTY <br /> I reviewed the Feasibility Study (FS) and Pilot Test Work Plan (Workplan), received 26 May 2011 from <br /> Stantec, the lead consultant for the above sites. The FS reviewed the following soil and groundwater <br /> remediation technologies and provided a recommendation to conduct a Pilot Test prior to submittal of a <br /> Corrective Action Plan. The Workplan provides the details for the Pilot Test at the Chevron site. <br /> The FS provides summaries of remedial work conducted to date for each of the above commingled <br /> plume sites, and also two neighboring sites (1426 S. Lincoln St., and 515 W. Charter Way) adjacent to <br /> the commingled plume. The FS compared soil vapor extraction with air sparging (SVE/AS), in-situ <br /> chemical oxidation (ISCO), and biosparging (BSP). While the FS did not compare costs for the three <br /> technologies, previous FS conducted at similar sites in Stockton show that the three technologies are <br /> reasonably comparable in cost and effectiveness. The FS expressed concerns that ISCO might <br /> damage metal components of the LISTS system, which is a valid concern if chemicals are injected <br /> shallowly into soils near the USTs system. BSP was also included in the above corrosion concerns. <br /> SVE/AS was effective for remediation at the 1426 S. Lincoln St, and was effective at pilot scale testing <br /> at 515 W. Charter Way (full scale SVE/AS installation is in progress). The FS recommended SVE/AS <br /> at the Chevron site as the safest effective technology to reach remedial goals. The Workplan <br /> proposed installation of one SVE (VE-1) screened from 14' below ground surface (bgs) to 19' bgs; two <br /> AS (AS-1 and AS-2) screened at 36' to 38' bgs and 26' to 28' bgs, respectively; and two soil vapor <br /> monitoring wells (PZ-1 and PZ-2) located 10' and 20', respectively, from VE-1 and screened from <br /> 14' bgs to 19' bgs, to evaluate SVE/AS performance by providing data for the SVE radius of influence. <br /> The Workplan is appropriate and necessary, and is approved for pilot testing SVE/AS as a prelude to <br /> submittal of a corrective action plan. Per the master schedule submitted to me on 5 May 2011 by <br /> Stantec, well installation fieldwork will commence upon State Water*Resources Control Board UST <br /> Cleanup Fund pre-approval of CP0057 costs, estimated date as 1 November 2011. Please expedite <br /> the schedule where possible, and give the San Joaquin County Environmental Health Department and <br /> myself at least three business days notice prior to start of fieldwork. If you have any questions, you <br /> can contact.me at (916) 464-4615 or I can be reached by e-mail at jbarton(o�waterboards.ca.gov. <br /> James L.L. Barton, P.G. <br /> Engineering Geologist <br /> cc: See CP0057 Distribution List <br /> California Environmental Protection Agency <br /> OaRecycled Paper <br />