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detectable concentrations of MTBE, toluene, and total petroleum hydrocarbons as gasoline <br /> (TPHg) <br /> IIn May 2003, GHH Engineering, Inc (GHH) supervised the advancement of three soil borings, <br /> SB2, SB3, and SB4, at the locations shown on Figure 2 Soil samples from SB3 and SB4 <br /> contained detectable concentrations of MTBE, and soil samples from S133 also contained <br /> detectable concentrations of benzene, ethylbenzene, and xylenes Groundwater samples collected <br /> from S133 and SB4 contained detectable concentrations of TPHg, total petroleum hydrocarbons <br /> as diesel (TPHd) and MTBE The groundwater sample from boring S133 also contained <br /> detectable concentrations of benzene, ethylbenzene, and xylenes <br />' 2.0 METHODS AND PROCEDURES <br /> To evaluate the extent of impacted groundwater at the site, a total of three soil borings were <br />' advanced and completed as groundwater monitoring wells in the vicinities of the former USTs <br /> and the fuel dispensers All field activities were performed in general accordance with GHH <br /> Engineering's Additional Assessment Workplan, Jays Mina-Mart, 3302 N West Lane, Stockton, <br /> California, dated August 2003 This workplan was approved by SJEHD on September 30, 2003 <br /> 2_1 Drilling Activities <br /> On January 12 and 13, 2004, an ATC geologist supervised the advancement of three soil borings <br /> to approximately 65 feet bgs A site plan with soil boring locations is shown on Figure 2 <br /> Woodward Drilling, California License C57 710079, advanced the borings utilizing a hollow <br /> stem auger drill rig Soil samples were collected from borings MW1, MW2, and MW3 at five- <br /> foot intervals in stainless steel sampling tubes The cored samples and drill cuttings were <br /> characterized for soil type, moisture content, and visual evidence of petroleum hydrocarbons A <br /> photo-ionization detector (PTD) was used as a field-screening device for the detection of <br /> petroleum hydrocarbon vapors in drill cuttings and cored samples A field geologist logged drill <br /> cuttings and soil samples utilizing the Unified Soil Classification System Descriptions of soil <br /> types encountered and sample collection intervals are included on the boring/well logs contained <br />' in Appendix A Soil borings MW1, MW2, and MW3 were then completed as groundwater <br /> monitoring wells Drill cuttings were temporarily stored on site in 55-gallon DOT approved steel <br /> drums <br /> 2�2 Soil Sample Analyses <br />' Selected soil samples were kept on ice and delivered under chain-of-custody documentation to <br /> State-certified Argon Laboratories Inc (ELAP Cert No 2359) in Ceres, California for chemical <br /> analysis Selected soil samples were analyzed by Argon Laboratories for TPHg and TPHd by <br /> EPA Method 801513, BTEX by EPA Method 8021B, and MTBE, TBA, tertiary amyl methyl <br /> ether (TAME), ethyl tertiary butyl ether (ETBE), di-isopropyl ether (DIPS), 1,2-dichloroethane <br /> (1,2-DCA), and ethyl dibromide (EDB) by EPA Method 8260B Two of the soil samples were <br /> i <br /> W 1268741reportslsum doe 2 <br />