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1 1.0 Introduction <br /> • This report discusses the installation and development of three monitoring wells and the <br />' subsequent quarterly groundwater sampling event performed in July 2003 at the SBC facility <br /> (formerly Pacific Bell) located at 10 East 12�h Street in Tracy,California (Figure 1) Well <br /> installation and groundwater monitoring and sampling were performed by Shaw Environmental, <br /> Inc (Shaw, formerly IT Corporation) on behalf of SBC, in order to comply with San Joaquin <br />' County Environmental Health Department's (SJCEHD) request to further evaluate the <br /> groundwater quality at the site <br />' 1.1 Site Description <br />' The SBC facility occupies approximately 0 S acres and is located in predominately residential <br /> and commercial part of Tracy, California The prominent site feature is a single-story building <br /> housing telecommunications switching equipment and offices on the western and southern <br /> portion of the site The remainder of the site is paved with asphalt and used for the parking of <br /> SBC fleet vehicles (Figure 2) In late 2002, an 8,000-gallon underground storage tank (UST) <br />' containing diesel fuel for an emergency backup generator was installed in the eastern portion of <br /> the site <br /> Groundwater has been encountered in tank removal and soil boring investigations at depths <br /> ranging from 11 feet to 14 feet below surface grade (bsg) Data from groundwater monitoring <br /> programs conducted on nearby properties indicates the regional groundwater gradient is generally <br /> directed to the north <br /> 1.2 Site Background <br />' In February 2002, a 500-gallon heating oil UST was encountered on the southeastern portion of <br /> the site during grading activities for the building expansion The age of this UST is unknown, <br /> however, it is believed the UST was used to supply fuel for the heating system of a former <br /> residential structure on the site, hence tank installation likely occurred one-half century or more <br /> 1 ago This UST was removed in early 2002 No petroleum hydrocarbon analytes were detected in <br /> a soil sample collected from the base of the UST excavation (IT Corporation [IT], 2002a) <br /> In March 2002, a 2,000-gallon diesel UST was removed about 120 feet form the former heating <br /> g <br />' oil UST The tank had contained fuel for an emergency backup power generator During <br /> removal activities, groundwater was encountered at a depth of approximately 12 feet bsg A soil <br /> CNCD/08-11-0310 SHAREIl13T/03-0096 doc l <br />