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1 <br /> ' and collection of soil samples Excavation procedures are scheduled to commence immediately <br /> following the removal of three steel-underground storage tanks (USTs) at the site <br /> ' Soil will be excavated using a backhoe or an excavator Soil will excavated to a depth of one to two <br /> feet below the can ent depth of the UST inverts Soil will be placed mto an excavation soil bin for <br /> ti ansportatlon to an appropriate landfill class I landfill at Waste Management at Kettleman Hills or <br /> ' class II landfill at Forward Landfill at Stockton Excavated soil will be field screened foa the pi esence <br /> of volatile organic compounds using an OVM, however, due to the release of waste fluids all waste <br /> ' placed into the bins will be disposed at an appropriate landfill <br /> Following the excavation and sampling clean and apps opriate backfill will be placed into the <br /> ' excavation <br /> ' PREVIOUS SITE INVESTIGATION <br /> On 23 and 24 October 2001, four soil probe borings(B I through 134)were advanced at the site under <br /> t EHD oversight Probe borings were advanced in formes UST excavation and west, southwest and <br /> east of the formes UST area to collect soil and grab water samples Probe boring B 1 was advanced <br /> to a total depth of 65 feet below surface grade (bsg) and borings B2 through B4 were advanced to <br /> ' 40 feet bsg Analytical data is presented on the attached tables Locations of the soil probe bormgs <br /> aj e illustrated on Flgui e 2 <br /> The most intensely hydrocazbon-impacted soil was encountered in the area of the former USTs <br /> (boring Bl), contaminants were not detected in analyzed soil samples collected from borings B2 <br /> ' thiough B4 At boring location B 1,petroleum hydrocarbons were detected in collected soil samples <br /> to depths of 30 feet bsg, but generally was not detected in soil samples from 40 feet bsg and below <br /> The highest hydrocarbon concentrations were encountered at depths between 10 and 20 feet bsg <br /> Hydrocarbon-impacted ground water was encountered to all four soil bonngs The highest <br /> concentration of dissolved hydrocarbons quantified as TPH-g,TPH-d and overall BTEX compounds <br /> ' were present in a water sample collected at 40 feet bsg fiom boring B1, at the former UST area <br /> Howevei, dissolved TPH-g and BTEX concentrations decreased radially northwest, southwest and <br /> east away from the area of the UST release In addition, dissolved TPH and BTEX were detected at <br /> ' low concenti ations in a grab ground water sample collected from 60 feet bsg at boring B I <br /> ' GROUND WATER MONITORING WELL INSTALLATION <br /> On 13 and 14 August 2002, five ground water monitoring wells were installed near the UST area <br /> ' (MW-1 though MW-5)to quantify the hydrocarbon concentration in ground water and determine the <br /> direction of ground water flow Field work was preformed as described in the AGE-prepared <br /> Monitoring Well Installation Work Plan, dated 08 July 2002, as amended and approved by the San <br /> ' Joaquin Country Environmental Health Department (EHD) by letter dated 18 July 2002 <br />