Laserfiche WebLink
31 January 2005 <br /> AGE-NC Project No 96-0232 <br /> Page 3 of 9 <br /> without a preservative and into 40-m1 EPA-approved volatile organic analysis (VOA) vials <br /> containing 0 5 ml 18% hydrochloric acid as a sample preservative Care was taken to ensure that <br /> visible air bubbles were not present in the vials after filling and capping Ground water sample <br /> containers were labeled with the well designation, date, time, and sampler's initials <br /> 2 3 LABORATORY ANALYSIS OF GROUND WATER SAMPLES <br /> Each ground water sample was logged on a chain of custody form,placed in a chilled container and <br /> transported to a California DHS-certified laboratory for analysis for <br /> • TPH-g and TPH-d by EPA Methods 5030B/8015Cm and 3510C/8015C, respectively, and <br /> • MTBE by EPA Method 8260B <br /> 24 FINDINGS <br /> Ground water elevation, flow direction and gradient were determined from field data collected on <br /> 27 December 2004, the contaminant impact to ground water was quantified by laboratory analysis <br /> of water samples collected on 27 and 28 September 2004 <br /> 2 4 1 Ground Water Elevation and Gradient <br /> The depths to ground water were measured at between 1175 feet(MW-18)and 15 90 feet(MW-9C) <br /> below the tops of the well casings on 27 December 2004, ground water elevations were calculated <br /> to be between 0 92 feet (MW-13B) and 2 20 feet (MW-I OE) below mean sea level (MSL) <br /> Ground water elevation data collected from Flag City Chevron wells MW-9 (A-C),MW-11 (A-D), <br /> MW-13 (A-D), MW-16, MW-17, MW-18 and Three B's Truck Plaza wells MW-6, MW-9 (A-E) <br /> and MW-10 (A-F) on 27 December 2004 is depicted on cross section C-C' (Figure 3), by <br /> determining the difference between ground water elevations (dh) and dividing by the difference of <br /> the screen interval midpoints (dl), the vertical gradient between adjacent screen intervals was <br /> calculated Generally,near neutral vertical gradients were observed between the First Zone, Second <br /> Zone and Rocky's Upper Zone, very slight downward vertical gradients were observed between <br /> Secondary Aquifer Zone and Primary Aquifer Zone (Figure 3) <br /> The 27 December 2004 ground water elevation data collected from the Flag City Chevron site and <br /> the adjacent Three B's Truck Plaza site were plotted for the informal First Zone, Second Zone, <br /> Advanced GeoEnviron mental,Inc <br />