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Y ! x { 1 <br /> i <br /> 1 ! 1 <br /> r <br /> 29 December 1999 ' f <br /> . AGE-NC Project No 97-0312 ' <br /> ,5 <br /> ' V ' ' a l [ , , , { ♦ M1 { r <br /> Page 6 of 9 <br /> ! 4 <br /> J <br /> L <br /> operation of the former product USTs The volume of impacted soil was subdivided as illustrated <br /> in Figure 12 and, the volume of each section was estimated An average concentration of <br /> hydrocarbons was estimated from soil samples collected and the mass of contaminants was' <br /> calculated Calculations were performed separately for both gasoline-range and diesel-range <br /> compounds' Mass calculations, conversion factors'and assumptions are included in Appendix E <br /> 3 8 PURGE/DECON WATER DISPOSAL <br />' On 08 October 1999, water generated during purging of monitoring wells and decontamination of <br /> augers from drilling was disposed Approximately 710 gallons of water were transported under <br /> n hazardous waste manifest by Nor Cal- Oil of Denair, California 'Water was transported to <br />' AmeriClean, Inc in Silver,Spnngs,Nevada for disposal The manifest is included in Appendix F <br />' 4.0. FINDINGS <br /> • Hydrocarbon-impact to soil-and ground water was inferred from laboratory analysis and field <br />' observations Ground water elevations were determined by subtracting the measured depths-to-water <br /> from the surveyed casing elevations (Table 1) Ground water flow direction was determined by <br /> contouring the water elevations on a scaled site plan(Figure 4) <br /> t <br /> 4 1 'GROUND WATER ELEVATION AND GRADIENT <br /> Ground water elevation decreased an average of 6 93 feet at the former USTs location since the June <br /> 1999 monitoring event Ground water flow direction was inferred to be northeasterly with a gradient <br /> of 6 0012 ft/ft The flow,direction is similar to previous monitoring events Figure 4 - Ground Water <br /> Elevation depicts the contours for September,1999 The gradient map was expanded to include data <br /> from monitoring well MW-1, located at 3400 Newton Road <br /> Static ground water was'approximately 6 to 7 feet above the screened interval in UST-2, UST-3 and <br />' UST-4, and approximately 4 feet above the screened interval in UST-6 Ground water was within <br /> the screened interval of UST-5 <br /> 4 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> TPH-g,TPH-d and BTEX compounds were detected in the water samples collected from monitoring <br /> well UST-5 at concentrations of 720 parts per billion (ppb, reported as micrograms per liter), 250 <br /> , L <br /> Advanced GeoEnvironmental,Inc <br /> r <br /> 1 r t <br /> r � <br /> r' + <br />