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29 September 1995 <br /> . AGE-NC Project No 95-0139 <br />' Page 4 of 7 <br /> No 2 were composrted 4 1 for analysis Two composite samples from Stockpile No 2 were also <br /> tanalyzed for total lead in accordance with EPA method 7420 <br /> Water was removed during excavation using a submersible pump,the water was placed in two 10,000 <br />' gallon temporary storage tanks on-site On 14 February 1995, water samples were collected from the <br /> dewatering tanks using disposable plastic bailers The samples were transferred into 40-m1 EPA vials <br /> preserved with hydrochloric acid and 1-liter amber bottles The samples were transported in a chilled <br /> container under chain-of-custody to MAI and composrted for analysis of TPH-g, TPH-d and BTE&X <br /> in accordance with EPA methods 8015m and 8020 <br />' On 24 March 1995, water samples were again collected from each dewatering storage tank by a <br /> representative of GeoAnalytical Laboratories, Inc Each sample was analyzed for TPH-d to <br /> accordance with method 3 510 LUFT <br /> Results of the second sampling of the storage tank indicated that water in Tank No 1 did not contain <br /> petroleum hydrocarbon compounds while water in Tank No 2 continued to contain low <br /> concentrations of hydrocarbons The City of Tracy permitted discharge of Tank No 1 directly to a <br /> . sanitary sewer outlet on-site Water in Tank No 2 was treated by carbon filtration, tested and, <br />' following confirmation, it was discharged to the sanitary sewer <br /> In March 1995, two 12,000-gallon USTs were installed in the excavation by SEMCO Pea gravel was <br /> imported to backfill the remaining volume of the excavation A concrete slab was then installed over • , , <br /> the tank area <br /> 3 2 MONITORING WELL PURGE PROCEDURES <br /> On 26 June 1995, a Solinst water level meter was used to measure the depth to water in each well <br /> relative to the top of the casing The relative ground water elevations and hydraulic gradient were <br />' determined from these data(Table 3) <br /> After depth to ground water measurements, a submersible pump was used to remove standing water <br /> from each well Approximately 5 gallons of water were removed from each well to stabilize <br /> temperature, pH and conductivity Ground water parameters were measured at one-gallon intervals <br /> using an ICM water analyzer All purging equipment was decontaminated in an alconox solution and <br /> rinsed twice after each well was purged The purged water was stored in 55-gallon drums on-site <br /> Stabilization data and field logs are included in Appendix B <br /> 1 <br /> 1, Lei` r1 tz ,lo 4 tr <br />