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Ms Margaret Lagorio Project 880-040 IA <br /> November 11, 2002 <br /> Page 2 <br /> Remedial activities conducted on January 26, 2000, included removal of approximately <br /> 262 tons of impacted soil in the area below dispenser and product lines Excavation <br /> 1 areas were selected based on the January 7, 2000 sampling results Excavation was <br /> restricted laterally by concrete canopy footings and asphalt surfacing Due to close <br /> proximity of groundwater, the maximum excavation depth was 10 feet bgs Results of <br /> soil sampling and excavation were reported in IT's, Product Line Upgrade and Soil <br /> Excavation Report, dated March 15, 2000 The San Joaquin County Environmental <br /> Health Department (SJCEHD) requested in a April 24, 2000 letter, further delineation of <br /> soil and groundwater impacts <br /> ' On August 15 and 16, 2000, a total of five Geoprobe° borings (GP-1 through GP-5) <br /> were completed using a direct push rig The borings were advanced to groundwater, at <br /> which time a discrete water sample was collected Following groundwater sample <br /> collection the borings were continued to a maximum depth of 30 feet bgs <br /> On September 6, 2000, three groundwater monitoring wells (MW-1 through MW-3) <br /> were installed The well locations were selected based on the Geoprobe° investigation <br /> results Well locations are shown on Figure 1 Quarterly groundwater monitoring and <br /> sampling was initiated in September 2000 <br /> In their letter dated October 31, 2001, the SJCEHD requested a work plan to define the <br /> vertical and lateral extent of soil and groundwater contamination and determine an <br /> interim remedial alternative to control the off-site migration of methyl tert-butyl ether <br /> (MtBE) A work plan dated December 12, 2001 was prepared describing the <br />' implementation of a 5-day dual phase extraction event, the installation of two down <br /> gradient wells, and one deep soil boring The work plan was approved by the SJCEHD <br /> on December 31, 2001 <br /> On May 22 and 23, 2002, Shaw observed the drilling of one deep soil boring and the <br /> installation of two monitoring wells (MW-4 and MW-5) The vertical extent of <br /> hydrocarbon impact appears to have been defined by the deep soil boring <br /> 1 <br /> • <br /> SAC 1N LSacDP120021PRJ\PJ8188018800401 A tab doc-021d 1 <br /> (01070000) <br />