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30 March 1999
<br /> AGE-NC Project No 95-0173
<br /> Page 4 of 5
<br /> 4.0. SUMMARY AND CONCLUSIONS
<br />' w the area of wells MW-1 MW-2 MW-3 MW-6
<br /> •
<br /> Groundwater monitoring data collected in e ,
<br />' MW-8,MW-9,MW-10,NW-11, MW-12 and VW-I indicated a ground water flow direction
<br /> generally toward the northeastat a gradient of 0 003 ft/ft, data collected in the area of wells
<br /> MW-4, MW-5 and MW-7 indicated a ground water flow direction generally toward the
<br /> southeast at a gradient of 0 003 ft/ft Due to the low gradient at the site, slight variations in
<br /> ground water measurements or changes of recharge/discharge of the local ground water could
<br /> greatly modify ground water flow direction
<br />' Between the October 1998 and the January 1999 ground water monitoring events, ground
<br /> water elevation at the site increased an average 0 88 feet
<br />' Ground water was approximately 4 to 5 feet above the screened intervals in monitoring wells
<br /> --MW-1, MW-2, MW-3 and MW-4, ground water was approximately 24 to 34 feet above the
<br /> screen intervals at AW-1B and AW-2B Therefore,these wells are "drowned", and may not
<br /> tyield samples fully representative of ground water conditions near the top of the saturated
<br /> zone
<br /> • From October 1998 to January 1999, a decrease in dissolved petioleum hydrocarbon
<br /> concentrations was observed from well MW-6 (Table 2) Conversely, increases were
<br /> observed from wells MW-3, MW-4, VW-1, AW-1B and AW-2B <-,,& �a 'j-'o-Q- 0,1twuk
<br />' • TPH-g was detected in water samples collected from wells MW-I through MW-4, MW-6,
<br /> MW-9, VW-1, AW-1B and AW-2B at concentrations ranging to 260.000 micrograms per
<br />' liter(/.)g/1) TPH-d was detected in water samples collected from wells MW-1 through MW-
<br /> 4, MW-6, MW-8, MW-11, MW-12, VW-1, AW-1B and AW-213 at concentrations ranging
<br /> to 19,000 µg/l, however, the laboratory reported that the diesel chromatograms for the
<br />' samples did not have typical diesel characteristics
<br /> • MTBE was detected from wells MW-5, MW-8, MW-9 and MW-10 utilizing EPA Method
<br />' 8020 at concentrations as high as 3 5 µg/l, MTBE was not confirmed in any water samples
<br /> utilizing EPA Method 8260
<br /> • BTEX compounds were detected in ground water samples collected from wells MW-1
<br /> 1 1 I' l A I l T i MW-8,
<br /> I n t I T n T� r I T ,n i [', 1 1 I, "I T Y•1 (T I N T Y A I t T 171 -1 A 117
<br /> trlrougiiiv1W-+,IvjW-n,Iv1W-�, iviw-y,IVI�N-IV,MW-I I,IVIW-IL, VW-A, tw-10� uuHW-
<br /> 2B at concentrations ranging as high as 69,000 Azg11 (toluene, VW-1) The greatest benzene
<br />' concentration was detected in the water samples collected from well MW-3 at a
<br /> concentration of 22,000 4g11
<br /> • The elevated concentrations of petroleum hydrocarbons detected in samples collected from
<br /> wells VW-1,AW-1B,AW-2B,MW-2,MW-3 and MW-4 indicate that these wells are within
<br />' Advanced GeoEn%iron mental,Inc
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