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1 <br /> 3 <br /> Third Quarter 2001 Manitoring and Sampling Report and Pre-Closure Sampling Workplan October 4 2001 <br /> 7-Eleven Inc store#17847 1048 West Yosemite Avenue Manteca CA <br /> ' Sensitive Receptors <br /> As mentioned previously,a sensitive receptor evaluation for this site Indicates that the nearest public supply <br /> ' wells are approximately 993 feet to the north Two wells are also located approximately 4,956 feet southwest <br /> of the site <br /> Purge Water Transportation and Disposal <br /> All purge water generated during this quarterly monitoring and sampling event was stored in 55-gallon <br /> Department of Transportation (DOT)-approved drums pending characterization and proper disposal <br /> 1 Approximately 10 gallons of purged water generated during this sampling event will be removed from the site <br /> and transported to a licensed treatment and disposal facility <br /> Workplan for Pre-Closure Sampling <br /> Laboratory analyses for 1,2-DCA and EDB will be conducted on samples collected from the groundwater <br /> monitoring wells during the fourth quarter 2001 <br /> In addition,one soil boring is proposed to be installed as shown on Figure 2 to a depth of 20 feet below grade <br /> Direct-push hydraulic rig drilling methods will be used All drilling equipment will be cleaned prior to drilling, <br /> and sampling equipment will be washed in an Alconox0(detergent)solution and rinsed with water between <br /> sampling intervals All soil and rinse water generated during the drilling will be placed in labeled Department <br /> of Transportation (DOT)-approved 55-gallon drums and left on the site pending transportation and disposal <br /> The boring will be backfilled to grade with cementtbentonde and patched at grade to match the surrounding <br /> ' surface <br /> Continuous sod samples will be collected from 5 feet below grade to total depth using Geoprobe/Macrocore <br /> techniques Soil samples will be field screened for hydrocarbon vapors using a photo-ionization detector <br /> Sod will be logged using the Unified Soil Classification System by an IT Corporation field geologist working <br /> under the supervision of a California registered geologist One 6-inch sample tube from each 5-foot depth <br /> ' will be sealed,labeled,and placed on ice in an insulated container for transport under chain-of-custody to a <br /> state-certified laboratory for analysis of BTEX, MTBE and TPH-G using EPA Methods 8020/modified 8015, <br /> and for oxygenates analysis by EPA Method 8260 Selected samples will be analyzed based on field <br /> instrument readings and proximity to the capillary fringe <br /> One groundwater sample will be collected at the base of the boring using either a hydropunch or in <br /> temporanly-installed casing (sample collected using a disposable bailer) The water sample will then be <br /> transferred to 40-milliliter glass vials filled to zero headspace,acidified to a pH of 2,sealed with Teflons- <br /> ' septum caps, labeled, placed on ice in an Insulated container, and transported under chain-of-custody to a <br /> state-certified laboratory for analysis of BTEX and TPH-G using EPA Methods 8020/modified 8015, and for <br /> f oxygenates, 1,2-DCA,and EDB analysis by EPA Method 8260 <br /> ' 2175684 rpt <br />