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Ms Margaret Lagono Page 3 of 6 ' increased an order of magnitude in wells MW3 and MW 13 TPHg and BTEX concentrations are summarized in Table 2 Attachment B contains laboratory reports and chain of custody documentation No EDB or gasoline oxygenate additives except MTBE were detected in any site monitoring ' wells, however, the detection limits for some wells were elevated due to dilution MTBE was not detected in wells MW 1, MW2, MWS, MW6, MW8 and MW 10 through MW 13 MTBE increased in wells MW3 and MW4 Concentrations in these wells were 2,600 parts per billion ' (ppb), and 2,200 ppb, respectively In wells MW7 and MW9, MTBE was detected at concentrations of 12 ppb and 13 ppb, respectively 1,2 DCA was detected in well MW2 at a concentration of 15 ppb, and in well MW9 at a concentration of 6 2 ppb after being at non- detectable levels during the previous sampling event In well MWIO, the concentration of 1,2 DCA increased slightly, while the levels in wells MW 11 and MW 12 decreased since the last event Oxygenates, EDB, and 1,2 DCA analytical results are summarized in Table 3 Attachment B contains laboratory reports and chain of custody documentation Wells MW3 and MW4 located along the southern boundary of the subject property are affected ' by offsite release(s) as indicated by the continual increase in contaminant concentrations • Vapor Extraction Wells ' The potentiometric surface was above the screened interval in wells VW 1, VW3 and VW4 Groundwater samples were collected from vapor wells VW1 through VW6 Petroleum ' hydrocarbons were detected all samples collected from the vapor extraction wells Concentrations of TPHg ranged from 400 ppb to 260,000 ppb in vapor wells VW5 and VW1, respectively Benzene ranged from 13 ppb in well VW5 to 22,000 ppb in well VW 1 TPHg and ' BTEX concentrations are summarized in Table 2 Attachment B contains laboratory reports and chain of custody documentation ' Samples from vapor extraction wells VWI through VW6 were also analyzed for gasoline oxygenate additives, 1,2 DCA and EDB No gasoline oxygenate additives were detected, however, MDLs were elevated in some wells due to dilution 1,2 DCA was detected in vapor ' well VW4 at a concentration of 130 ppb, and EDB was detected in vapor well VW1 at a concentration of 1,200 ppb The detection of EDB in vapor well VW1 prompted a review of previous laboratory data Upon review, the laboratory determined that EDB had also been ' present above non detectable levels in the sample collected from vapor well VW 1 in August 2000 Oxygenate, 1,2 DCA and EDB concentrations are summarized in Table 3 Attachment B contains laboratory reports and chain of custody documentation ' In paired deep/shallow vapor wells VW1/VW2 and VW4/VW5, the wells with deeper screened intervals exhibited higher concentrations of target analytes than the shallower wells i roeklq=\4QM2"