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02 February 1996 <br /> AGE-NC Project No 95-0142 <br />' Page 3 of 4 <br />' 4.0. FINDINGS <br /> v 4 1 GROUND WATER GRADIENT AND DIRECTION <br />' The depth to ground water at the site ranged from 38 87 feet to 39 46 feet The data indicates an <br /> average increase of ground water elevation of nearly one-quarter of a foot since September of 1995 <br />' The ground water gradient maintained the eastward regional trend calculated from previous sampling <br /> events The gradient becomes more shallow to the east of the site The relative elevation of ground <br /> water is illustrated on Figure 3 -Relative Ground Water Elevation <br /> 4 2 HYDROCARBON IMPACTED GROUND WATER <br /> TPH-g was detected in each monitoring well ranging from 51 pg/l' (parts per billion ppb) in MW-1 <br />' to 230,000 ppb in VE-1 BTE&X were detected in samples from MW-3 and VE-1 at concentrations <br /> ranging from 15 ppb (toluene in MW-3) to 52,000 ppb (toluene in VE-1) Analytical results of the <br /> ground water samples are summarized in Table 2 The laboratory report (MAI Laboratory I D Nos <br /> 59831 - 59834) and chain-of-custody are included in Appendix B <br />' 5.0. CONCLUSION&AND RECOMMENDATIONS <br /> 5 1 HYDROCARBON IMPACTED GROUND WATER <br />' Ground water gradient calculations based upon data collected during the December 1995 sampling <br /> indicates that gradient direction at the site has changed, rotated approximately 20° to the east The <br />' greatest concentrations of hydrocarbons are present in VE-1, near the former UST excavation <br /> Between September and December 1995, concentrations of petroleum hydrocarbons decreased <br />' slightly in MW-1 but increased in MW-3 Based upon the most recent groundwater data, it appears <br /> that wells MW-1, MW-2 and MW-4 represent the edges of the dissolved hydrocarbon plume <br /> We do not recommend the installation of additional ground water monitoring wells at this time <br /> However, additional wells may be required in the future, if the dissolved plume migrates south of <br /> MW-2 or northeast of MW-4 <br /> The next quarterly ground water monitoring is scheduled for March 1996, wells MW-1 through MW- <br />' 4 and VE-1 are scheduled to be sampled <br /> 1 <br />