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L & M OPERABLE UNIT - FIRST QUARTER 2012 SITE STATUS, REMEDIAL SUMMARY,
<br />AND GROUNDWATER MONITORING REPORT
<br />Appendix B
<br />Page 6
<br />In September 2006, SECOR, along with Entact Environmental Services, commenced pipeline
<br />abandonment and removal activities at 525 West Weber Avenue in the Waterfront Towers
<br />Parking facility in accordance with Stantec’s Pipeline Removal, Abandonment, Soil Excavation,
<br />On-Site Horizontal SVE Well Installation, and Horizontal SVE Well Installation Beneath Delta
<br />View Apartments Report and Work Plan for Pipeline Removal, Abandonment, and Soil
<br />Excavation in Waterfront Towers Parking Lot dated February 10, 2005. A report entitled
<br />Pipeline Removal, Abandonment, Soil Excavation, and Parking Lot Reconstruction summarizing
<br />remedial activities and parking lot restoration at the Waterfront Towers Parking facility was
<br />submitted on June 25, 2008.
<br />On May 31, 2007, optimization of the DPE/SVE system, in accordance with SECOR’s Work
<br />Plan for Additional DPE Feasibility Testing and Expanded Remedial System Installation,dated
<br />January 4, 2006, was completed and permitted to operate by the city of Stockton. A soil vapor
<br />extraction system start-up and dual phase augmentation report was submitted on June 25,
<br />2008.
<br />On June 21, 2007, well MW-6 on the MOU was destroyed and abandoned on behalf of the City
<br />of Stockton and under the supervision of Golden State Environmental due to planned
<br />excavation and construction activities.
<br />From July 28 through September 26, 2008, additional assessment activities were conducted at
<br />the Site. Five B-zone groundwater monitoring wells (MW-56 through MW-60), seven C-zone
<br />groundwater monitoring wells (MW-61 through MW-67), and seven D–zone groundwater
<br />monitoring wells (MW-68 through MW-74) were installed. Results were summarized in Stantec’s
<br />Additional Deep Groundwater Zone Assessment Report dated January 26, 2009.
<br />In November 2008, Treadwell and Rollo (T&R) on behalf of the City of Stockton abandoned
<br />monitoring wells MW-8, MW-10, MW-11, MW-39, MW-40, MW-41, and MW-53 due to
<br />excavation activities on the UOU. These wells have yet to be reinstalled at the site.
<br />In January 2009, T&R, on behalf of the city of Stockton, concluded their excavation activities on
<br />the Unocal Operable Unit adjacent to the L&M OU. Treadwell and Rollo submitted their report
<br />of findings entitled Removal Action Completion Report Unocal Operable Unit on Area 2A to the
<br />RWQCB-CVR on August 5, 2009. A groundwater collection trench, extending north-south, was
<br />left in the substrata approximately 15 feet bgs and along the eastern boundary of the excavation
<br />which paralleled the major pipeline removed during the investigation.
<br />In March 2009, Wallace Kuhl Associates (WKA), on behalf of the city of Stockton, concluded
<br />excavation, installation of exploratory borings, and UST removal activities on the property
<br />adjacent to the Waterfront Towers Parking Facility to the north and west. Wallace Kuhl and
<br />Associates submitted their report of findings entitled Stockton Promenade Underground Storage
<br />Tank Removal Report-Former North Edison Street to the RWQCB-CVR on June 8, 2009.
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