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i <br /> 29 March 1996 <br /> AGE-NC Project No 95-0125 <br /> Page 4 of 5 <br /> 4.0. FINDINGS <br /> 4 1 GROUND WATER ELEVATION AND GRADIENT DIRECTION <br /> When measured ora- 6 March 1996, the depth to ground water at the site ranged from 5 1 to 6 8 feet <br /> bsg The relative elevation of ground water in each well was calculated by subtracting the ground <br /> water depth from the surveyed casing elevations, casing elevations were surveyed relative to MW-1, <br /> which was assigned an arbitrary elevation of 100 00 feet Table 1 includes the ground water <br /> elevations The relative ground water elevation rose approximately 1 foot between the October 1995 <br /> and the current monitoring events <br /> Figure 3 -Relative Ground Water Elevation, illustrates the ground water elevations at the site, based <br /> upon data collected dunng this monitoring event Ground water flow in the area is toward the north, <br /> with a level plane evident from MW-2 and MW-10 This northeast trending "trough" has been <br /> apparent during the last two monitoring events The overall northward trending flow is consistent <br /> with the regional ground water flow in the area <br /> 4 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> TPH-g was detected in MW-2 and MW-6 at concentrations of 500 and 340 µg/l (micrograms per <br /> liter, equivalent to parts per billion ppb), respectively BTE&X were detected in MW-2 and MW-6 <br /> at concentrations up to 20 ppb (benzene, MW-2) MTBE was not detected in the sample collected <br /> from MW-6 Analytical results of ground water samples are summarized in Table 2 The laboratory <br /> report (Alpha Analytical Laboratory batch No 96-0306-026) and chain-of-custody are presented as <br /> Appendix B <br /> 5.0. CONCLUSIONS AND RECOMMENDATIONS <br /> 5 1 HYDROCARBON-IMPACTED GROUND WATER <br /> Based on the detection of TPH-g in ground water samples collected from MW-2 and MW-6, the <br /> current extent of dissolved petroleum hydrocarbons in ground water appears to be adequately <br /> delineated, being hnuted to a relatively small area in the vicinity of those wells Samples from wells <br /> MW-2 and MW-6 have consistently contained detectable concentrations of hydrocarbons <br /> Between October 1995 and March 1996, dissolved petroleum hydrocarbon concentrations increased <br /> in MW-2 and decreased in MW-6 Additional monitoring and sampling of these wells should be <br /> conducted prior to determining any need for remediation We recommend scheduling the next <br /> quarterly monitoring for June 1996 <br />