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I12 February 1996 <br /> • AGE-NC Project No 95-0121 <br /> Page 3 of 4 , <br /> E <br /> I4.0. FINDINGS <br /> 4 1 RELATIVE GROUND WATER ELEVATION AND GRADIENT <br />�r The ground water elevation in each well was calculated by subtracting the depth to water from the <br /> surveyed casing elevation(Table 1) Ground water elevation at the site ranges from -18 05 to -18 68 <br /> feet The average ground water elevation at the site was unchanged, rising in 6 wells and dropping <br /> in 3 wells between July and November 1995 , <br /> Ground water flow direction was determined to be northeast (Figure 3) 'The gradient is slightly <br /> shallower than during previous morutonng events <br /> 42 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br />' TPH-g was detected in samples from MW-1 through MW-4, MW-6 and MW-7 at concentrations <br /> ranging from 940 gg/l (parts per billion ppb,MVV-6)to 21,000 ppb (MW-2 and MW-3) TPH-d was <br /> detected in samples from IVM-1 through MW-3 at concentrations ranging from 320 ppb (MW-1) to <br /> 1,300 ppb(NM-2) The laboratory report noted that the diesel chromatogram from MW-3 was not <br /> consistent with typical diesel standards <br />' BTE&X were detected in samples from MW-1 through MW-4, MW-6 and MW-7 at concentrations <br /> ranging from 0 76 ppb(xylenes, MW-6)to 10,000 ppb(benzene, MW-2) Benzene was also detected <br />' in the sample from MW-8 at 0 37 ppb <br /> r ' <br /> No petroleum hydrocarbons were detected in MW-5 or NAW-9 The analytical results of ground water <br />' samples are summarized in Table 2 The laboratory report (WEST Sample Log 13453) and chain-of- <br /> custody form are included in Appendix B <br />' 5.0. CONCLUSIONS & RECOMMENDATIONS 4 <br />' Between July and November 1995, dissolved hydrocarbons increased significantly in well MW-2 <br /> However, in all other wells at the site, concentration's of TPH-g, TPH-d and BTE&X remained <br /> relatively consistent over the same period , <br />' The extent of dissolved hydrocarbons north of the former UST area has not been determined Based <br /> upon the present concentrations of dissolved hydrocarbons at the site, additional monitoring wells <br />' may be required north of monitoring wells MW-2 and MW-7 to determine the down-gradient extent <br /> . of the dissolved hydrocarbon plume <br /> I , <br /> I <br />