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i ' 230 ppb, MtBE in six of the ten deep wells at a maximum concentration of 1,300 ppb, and 1,2- DCA in seven of the ten deep wells at a maximum concentration of 24 ppb The deep and shallow zone are discussed further in Section 4 The historical groundwater gradient direction within the shallow zone at the site has been to the northeast at gradients ranging from 0 001 to 0 008 feet per foot The historical groundwater gradient direction within the deep zone at the site has been to the northeast at gradients ranging from 0 003 to 0 007 feet per foot Historical groundwater monitoring data is included as Tables 3 and historical gradient data is included as Table 4 23 Supply Well Survey According to IT's Site Assessment Report, dated February 25, 2000, IT performed a water supply well search to locate any water supply wells within 2,000 feet of the subject site Review ' of well logs at the California Department of Water Resources (DWR) indicated the presence of one water supply well within the 2,000-foot search radius, located at 1521 N Hunter Street, down gradient of the site Well construction details and usage of the well was not documented on the DWR well log The San Joaquin County Environmental Health Department (SJCEHD) attempted to locate the well, however the well was not found Additional well searches conducted in the area (adjacent LUFT site ARCO 4932, 16 E Harding ' Way) indicated that 4 wells were located approximately 2000 feet east (cross/down gradient) of the site at the Stockton State Hospital, one well located 2,000 feet northeast (downgradient) of the site (near Cemetery Lane and Harding Way) and one approximately 2,000 feet northwest '• (crossgradient) at the intersection of Wyandotte and Commerce (as indicated by SJCEHD in their letter dated Nov 21, 2000) The use of the 4 wells at the Stockton State Hospital was not indicated on the well logs The well at Cemetery Lane and Harding Way was indicated as ' industrial use and the well at Wyandotte and Commerce is a well owned by California Water Service but was not active The sensitive receptor survey is presented in SECOR's report Additional Site Assessment Report dated November 9, 2001 for ARCO 4932 A sensitive ' receptor map is included as Figure 3 24 Summary of Remedial Action ' Source removal conducted at the site to date consists of over-excavation of obviously impacted soil during the UST, dispenser and product line removal conducted in 1999 A total of approximately 1,707 tons of soil was transported off-site for disposal at the Forward Landfill in Manteca, California Historical maps showing areas of over-excavation is included in Appendix B Updated SCM doc 4 August 13,2004 ' 77CP 64409 05 0005