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5 <br /> 29 August 2001 , <br /> AGE-NC Project No 95-0144 <br /> Page 4 of 7 ; <br /> 2 6 BACKFILLING OF EXCAVATION <br /> The excavation was backfilled to approximately 4 feet bsg using 5/16-inch pea gravel and to surface <br /> 1 grade using sand ' <br /> I , <br /> 2 7 PURGE WATER WASTE DISPOSAL a <br /> On 04 .Tune 2001, approximately 375 gallons of non-hazardous purge water were pumped from <br /> on-site 55-gallon drums The purge water had been generated during ground water monitoring <br /> activities Pumping and disposal was completed by American Valley Waste Oil, Inc of Delhi, <br /> California All waste was disposed at Seaport Environmental located in Redwood City, California <br /> A copy of the waste disposal manifest is included in Appendix D <br /> 3:0. FINDINGS ' <br /> Ground water elevation and flow direction were inferred from field data, hydrocarbon-impact to _ <br /> ground water and soil was quantified by laboratory analysis of the ground water and soil samples <br /> 3 1 ANALYTICAL RESULTS OF SOIL STOCKPILE SAMPLES _ <br /> ' No detectable concentrations of PCBs or SVOCs were reported by PET The laboratory report(PET , <br /> Sample ID PEI 1421-01) and chain-of-custody form is included in Appendix E <br /> ' 3 2 RELATIVE GROUND WATER ELEVATION AND GRADIENT - <br /> r , <br /> The elevation of ground water in each well was calculated by subtracting the depth to water from the <br /> surveyed casing elevation(Table 1) Between February 2001 and May 2001, ground water elevation <br /> ' increased between 0 06 feet and 0 15 feet in wells MW-1, MW-2, MW-4, MW-5, MW-8, MW-11, = <br /> MW-12, MW-13 and MW-20A Ground water elevation decreased between 0 01 feet and 0 10 feet <br /> m wells MW-19A, MW-19B, MW-20B and MW-21 B Ground water elevation was unchanged in <br /> MW-21A The approximate hydraulic gradient for the May 2001 monitoring event was inferred to <br /> be 0 002 f1/ft with a north to northeast flow direction Ground water elevation contours derived from <br /> data collected on.21 May 2001 are depicted in Figure 3" Ground water was between approximately, <br /> ' 0 83 feet and 6 20 feet above the screened interval in monitoring wells MW-1, MW-2, MW-4, <br /> MW-5, MW-8, MW-11, MW-12, MW-13 and MW-18 Ground water was within the screened <br /> ' intervals of MW-I9A, MW-20A and MW-21A <br /> Advanced GeoEnvironmental,Inc <br /> S 4 <br />