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16 28 March 1997 <br /> AGE-NC-95-0103 - <br /> - - <br /> -Page 4 ofd <br /> - Piping was installed beneath the asphalt surface from a fenced enclosure on the west side of the site - <br /> '�f to wells VE-1, VE-2,VE-5, VE-6 and VW-1 for use in a vapor extraction system An internal <br /> - - _ combustion(IC)vapor extraction unit was installed at the site in approximately August 1996 Vapor _ <br /> extraction was attempted for several months, however, continuous operation of the extraction unit _was not successful' _ <br /> -Piping was also extended from the fenced enclosure to sparging point AS-1 -However, no attempt <br /> at air-sparging has been made Work was performed b Lush Geosciences who issued no reports <br /> . _ p _ Y p <br /> ;- regarding the setup and operatiofi of the IC unit - - <br /> _- <br /> -36-- PROCEDURES <br /> 31 - MONITORING WELL-PURGE PROCEDURES <br /> _ TQn 21 January 1997, a Solinst water level-meter was used to measure the depth to ground water in <br /> monitoring wells MW-1 through MW-5 relative to the'top of the each well's casing Monitoring_ <br /> wells MW-1 and MW-4 were checked foi the presence of free produo using an Ulla ' interface <br /> probe The relative ground-w--alvei elevations were calculated by subtracting the giound water depth <br /> - fiom the surveyed,casing elevation (Tabl&l) - <br /> After making and recording the depth to ground water measurements, monitoring wells MW-1 <br /> through MW-5 were purged-using a two-stage purge pump -The purge pump was washed in an <br /> Alconox solution and rinsed "ith tap water prior to purging each well A minimum of three well <br /> v61urnes of water--was removed from each well Ground water physicochemical parameters <br /> (temperature, pH and conductivity) were measured at regular intervals using an TCM model 52200 <br /> - water analyzer Purged water-NN as stored in 55-gallon drums on property adjacent to the site owned <br /> } Y <br /> by-Mr--Russell Chapin_Physicocliemical daia and field logs are included in Appendix A - <br /> ­32 3 2 COLLECTION-OF GROUND WATER SAMPLES <br /> - Water samples were collected from each purged well using new disposable bailers The samples <br /> "ere transferred t6-40-ml EPA-approvecl VOA vials containing 0 5 ml of 18% hydrochloric acid as <br /> s t _ :.a preservative and were transported in a chilled container, under chain-of-custody, to McCampbell <br /> - Analytical, Inc', (MAI) in Pacheco, California Each sample was analyzed for total petroleum <br /> - _-F hydrocarbons quantified as gasoline (TPH-g)and volatile organics (benzene, toluene, ethylbenzene <br /> and xylenes,=BTE&X)-in accordance with EPA methods 503018015m and 602, 'respectively <br />