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1 <br /> 11 April 2001 <br /> AGE-NC Project No 95-0143 <br /> Page 3 of 6 <br />' from the influent line on 05 October 2000 and from the influent and the effluent lines of the SVE <br /> unit on 16 October 2000 Following the shut down of the catalytic system samples were collected <br /> from only the influent lune on 06 December 2000, 18 December 2000 and 28 December 2000 (Table <br />' 5) All samples were collected into Tedlar bags and transported in a chilled container under chant-of- <br /> custody to a DHS-certified laboratory The samples were transported to MAI and were analyzed for <br /> TPH-g, BTEX and MTBE in accordance with EPA Methods 8015m/5030 and 8020/602 by MAI <br />' The depth to ground water and dissolved oxygen concentrations in ground water were measured on <br /> P �' xYg <br />' 15 November and. 28 November 2000 Ground water elevation data are summarized on Table 1 <br /> Dissolved oxygen data are summarized on Table 4 <br /> r2 4 HYDROCARBON MASS CALCULATIONS <br /> Operation time and flow rate were recorded during monitoring of the SVE system on field data <br />' sheets (Appendix D) The volume of extracted soil vapor removed was then calculated Analytical <br /> results for the five soil vapor samples collected from the SVE intake and the volume of soil vapor <br /> 1 • removed between sample collection divided into two data sets,based on the tune of collection of the <br /> soil vapor samples The mass of hydrocarbons removed from the site was then calculated The mass <br /> calculations are in Appendix E <br /> i <br /> 3.0. FINDINGS <br />' Ground water elevation was calculated and flow direction was inferred from field data, the <br /> hydrocarbon impact to ground water was inferred from laboratory analysis and field observations <br />' The approximate mass of hydrocarbons removed by soil vapor extraction was calculated <br /> 3 1 GROUND WATER ELEVATION AND GRADIENT <br /> The elevation of ground water in the nine wells was calculated by subtracting the depth to water from <br /> the surveyed casing elevation (Table 1) Ground water elevations decreased In the monitored wells <br /> an average 1 13 feet between the August 2000 and November 2000 monitoring events Ground water <br />' was within the screened intervals of MW-17 and each vapor well Ground water ranged from 0 09 <br /> feet to 7 06 feet above the screened interval in the other eight monitoring wells The approximate <br /> flow direction was toward the northeast at the subject property Ground water elevation contours <br />' for the November 2000 monitoring event are illustrated in Figure 3 <br /> Advanced GeoEnvirontntntai,Inc <br /> 1 r <br />