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i <br /> i <br /> Christopher M. Palmer, PG, CEG, HG, Consulting Hydrogeologist <br /> 1345 Kimberly Drive San Jose, CA 95118 ph.408/267-5238;fax 408/267-7396 <br /> CMPRGCEGHG@aol.com <br /> Wright was retained by the City to drill and sample three exploratory borings at <br /> the reported former underground tank pits in Sixth Street in February 2003. Sod <br /> boring samples collected in February 2003 showed that contaminants contained <br /> TPHG and TPHD in soil samples near the capillary fringe, with the highest values <br /> in B-2. Groundwater samples.from these borings showed TPHG and TPHD in <br /> Borings B-2 and B-3. These samples together with the inferred northedy <br /> w direction indicate <br /> that a dissolved plume has migrated groundwater flow p 9 <br /> Sixth Street and toward the Delta Disposal property line. <br /> Three groundwater monitoring wells were installed in 2008 as required by <br /> SJCEHD following a review of Wright's 2003 study. The .purpose of &0 V W- 01 <br /> installation and groundwater sampling was to evaluate.groundwater <br /> beneath the site. Wright presented this information together with <br /> monitoring p <br /> reports to the SJCEHD, who has concurred with the conckocion <br /> that the site qualified for site closure/NFAR in their case closure sum <br /> August 27, 2012. <br /> 3.0 Field Methods —Well Destructions <br /> Monitoring wells MW-1, MW-2, MW3 were destroyed using an approt <br /> and a SJCEHD representative observed the well destructions. The Or4ft-4Z <br /> groundwater and total depth of each weWwas measured prior to des <br /> compared to each well boring log and well construction detail. The . <br /> destruction was selected (one foot below the completed depth shov <br /> log) and the well casing, screen, filter pack and grout sealant was cern, <br /> _ <br /> :removed by drilling. Any groundwater displaced to the surface was purVeds <br /> containerized. <br /> The cement grout was mixed to the SJCEHD permit specification and Ow*4 <br /> placed in the borehole_using a tremie pipe, filling from the bottom to tcpr <br /> borehole (to the existing surface grade). The top of the borehole VMS thoft <br /> sealed with neat cement and sidewalk repairs were made as needed for lfw- Y <br /> 4.0 Drilling Materials Disposal <br /> The City of Tracy coordinated the destroyed well waste materials disposal vofth <br /> drilling contractor Technicon Engineering. Services, Inc. Safety Kleen Systems, <br /> Inc. transported the waste to Clean Harbors Buttonwillow, LLC California faces <br /> (see attached manifest). <br /> Page 2 of 4 <br />