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31 January 1997 AGE-NC Project No 95-0125 Page 5 of 7 portion of the school property An authorization for the uncontrolled soil aeration was granted by the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) In order to determine the effectiveness of the soil aeration treatment verify five soil samples were collected from the stockpiled soil excavated from the former USTs area Soil samples were collected from two feet below the surface of the stockpiled soil Soil samples were collected with metric soil sampling hammer, loaded with two 2 by 3-inch clean brass sampling sleeves Soil in the lead sample sleeve was preserved for laboratory analysis both ends of the lead sleeve were covered with Teflon sheets, capped and sealed with tape The samples were stored in a chilled container and transported under chain-of-custody to AAL Each sample collected was analyzed for TPH-g, BTE&X and MTBE in accordance with EPA methods 5030/8015m, 602 and 602, respectively 4.0. FINDINGS 41 GROUNDWATER ELEVATION AND GRADIENT DIRECTION When measured on 05 November 1996 the g depth to round water at the site ranged from 7 75 to p g S 42 feet bsg The relative ground water elevation at the site decreased approximately 0 25 feet between June and November 1996 The relative elevation of ground water in each well was calculated by subtracting the ground water depth from the surveyed casing elevations, casing elevations were surveyed relative to MW-1, which was assigned an arbitrary elevation of 100 00 feet Table 1 includes the ground water elevations Figure 3 -Relative Ground Water Elevation, illustrates the ground water elevations at the site, based upon data collected during this monitoring event Ground water flow in the area is toward the north The overall northward trending flow is consistent with the regional ground water flow in the area 4 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH-g was detected in MW-2 at concentrations of 72,ug/1 (micrograms per liter, equivalent to parts per billion ppb), respectively BTE&X were detected in MW-2 at concentrations up to 0 39 ppb (toluene, MW-6) Petroleum hydrocarbons were not detected in any of the additional monitoring wells sampled MTBE was not detected in the samples collected Analytical results of ground water samples are summarized in Table 2 -Analytical Results of Ground Water Samples The laboratory report (Alpha Analytical Laboratory batch No 96-1107-007) and chain-of-custody are presented as Appendix B