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I 1i <br /> I I <br /> . 23 December 2003 <br /> AGE-NC Project No 97-0333 l <br /> ' <br /> Page 6of11 ' E <br /> I <br /> r <br /> preservative Care was taken to ensure that visible air bubbles were not present in the vials after <br /> filling and capping Ground water sample containers were labeled with the well designation, date, <br /> time, and sampler's initial's <br /> 1 I ! I I{f <br /> 3 4 LABORATORY ANALYSIS OF GROUND WATER SAMPLES <br /> P 11 1 11 11 <br /> 1 <br /> Each ground water sample was logged on a chain-of-custody form,placed in a chilled container and <br /> transported to Cal Tech Environmental Laboratories, a California Department of Health Services <br /> ' (DHS)-certified laboratory for analysis for E <br /> I <br /> I <br /> y • TPH-g by EPA Methods 5030/8015M, <br /> • BTEX by EPA Method 8260B, and I <br /> •' Volatile organic compounds, including PCE, TCE, 1,2-DCA, EDB, MTBE, TAME,DIPS, <br /> I <br /> I' ETBE and TBA by EPA Method 8260B <br /> �I <br /> a Ir I I <br /> I ' <br /> I <br /> 35 FINDINGS <br /> Ground water elevation, flow direction and gradient were determined from field data collected on <br /> 18 August 2003, the contaminant impact togiound water was quantified by laboratory analysis of ' <br /> water samples collected on 19 and 20 August 2003 I' <br /> I I � <br /> r ! <br /> } I <br /> 3 5 1 Ground Water Elevation and Gradient ' <br /> r <br /> I <br /> The depths to ground water were measured at between 22 53 feet(MW-5)and 27 44 feet(MW-7C) E { <br /> below the tops of the well casings on 18 August 2003, ground water elevations'were calculated to <br /> ' be between 5 26 feet (MW-1IQand 9 44 feet (MW-5) above mean sea level (MSL) Based on <br /> current and previous!monitoring data collected from wells MW-1 through MW-13, ground water <br /> elevation at the site generally decreased an average,2 90 feet between the June 2003 and the August <br /> ' 2003 groundwater monitoring events The groundwater elevation is lower than previously recorded I' <br /> I <br /> A <br /> 1 I i IJ J l <br /> Ground water elevation data collected from multi-level wells MW-11, MW-12 and MW-13 on,18 <br /> August 2003 is depicted on cross section F-F'(Figure 3) The vertical gradients between adjacent <br /> screen intervals 'are r depicted on' cross section F-F', the vertical gradient was calculated by <br /> ' deterrnining the difference between ground water elevations(dh) and dividing by the difference of <br /> the screen interval midpoints (dl) Generally, a pronounced downward r gradient` was observed i <br /> between the First Zone and the upper,Second Zone'at all three well',locatioiis, a less pronounced ,F <br /> Advanced GeoEnnronmelntal,Ine <br /> II <br /> r 4 <br />