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PARSONS <br /> 2121 N.California Blvd.,Suite 500.Walnut Creek,CA 94596.(925)941-3700.Fax(925)979-9781 •v .parsons.com <br /> MEMORANDUM <br /> November 3, 2014 <br /> To: Mr.Jeff Gymer <br /> Project Manager <br /> Department of Toxic Substances Control <br /> 1515 Tollhouse Road <br /> Clovis, CA 93611 <br /> From: Mr. Mark Sarconi, Parsons <br /> On behalf of <br /> Ms. Melitta Rorty(Pacific Gas and Electric Company) <br /> Subject. Workplan for Abandonment of Environmental Monitoring and Remediation <br /> Features, PG&E Former Tracy MGP Site, 502 E. Grant Line Road, Tracy, CA <br /> Mr. Gymer, <br /> This memorandum presents a workplan for the abandonment of environmental monitoring and <br /> remediation features at the Former Tracy Manufactured Gas Plant (MGP) Site located at 502 E. <br /> Grant Line Road in the City of Tracy, California (Figure 1). The features to be abandoned <br /> include groundwater monitoring wells; groundwater extraction points (EPs); ozone injection <br /> points (OIPs); and soil gas probes. The abandonment of these features is being performed in <br /> response to DTSC's approval of regulatory closure of groundwater impacts at the Site in the no <br /> further action letter dated August 7, 2014 (DTSC 2014). <br /> 1.0 BACKGROUND <br /> Several rounds of environmental assessment have been performed at the Site including the <br /> following: a preliminary assessment (PA) (PG&E 1986); an initial site assessment (ISA) <br /> (PG&E 1989); historical groundwater monitoring associated with the removal of an underground <br /> storage tank (UST); a remedial investigation(RI) (Parsons 2008); supplemental geotechnical and <br /> environmental investigation (SGEI) (Parsons 2011); and pre-confirmation sampling. <br /> During the course of historical investigations and remediation activities, 22 soil gas probes and <br /> 11 groundwater monitoring wells were installed at the Site. <br /> Each of the 22 soil gas probes were installed to a depth of 5 feet bgs during the RI in 2008; six of <br /> the probes (A3-SGl/lA, A3-SG2, A3-SG3, D2-SGI, E2-SGI, and E3-SGI) were removed <br /> during soil remedial excavation activities in areas of impact (AOIs) 2 through 6. The remaining <br /> 16 soil gas probe locations, to be removed as part of the implementation of this workplan, are <br /> shown on Figure 2. <br /> 1 <br />