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C � C • 10 January 2001 'AGE-NC Project No 98-0533 ' Page 3 of 6 ' 3 4 GROUND WATER MONITORING WELL COMPLETION Pilot borings B-1,B-3 and B-4 were completed as ground water monitoring wells MW-1,MW-2 and ' MW-3 using two-inch diameter PVC casing with 0 020-inch slotted screen installed from 85 feet to 65 feet bsg and with blank casing extending to the surface The filter pack(No 2112 Lonestar sand) was installed from 85 feet to approximately 63 feet bsg The wells were then developed using a surge ' block to settle the sand pack A nominal 3-foot bentonite pellet plug was then installed above the filter pack and hydrated The wells were then grouted to near the surface with portland cement ' Water-tight, traffic-rated well boxes were then installed over the wells (ground water monitoring well design is shown in Figure 3) Finally,the casing elevation of each monitoring well was surveyed to the nearest 0 01-foot relative to San Joaquin County Bench Mark Datum BM#SR-07 J955 by ' representatives ofBaumbach and Piazza,Inc of Lodi,California, licensed surveyors(Appendix B) ' 3 5 MONITORING WELL PURGE PROCEDURES • On 05 July 2000, a Solinst water level meter was used to measure the depth to ground water in the three wells relative to the tops of the well casings The ground water elevations and gradient were determined from this data (Table 1) ' Afler recording water level measurements, a two-stage submersible pump was used to purge each monitoring well of standing water Approximately 8 gallons of water were removed from each well (approximately 3 casing-water volumes) Ground water temperature, pH and conductivity were ' measured at 2-gallon intervals during the purge process using a Hydac water analyzer Field data sheets are included in Appendix B Purged water was stored on site in labeled, 55-gallon DOT- approved drums 3 6 COLLECTION OF GROUND WATER SAMPLES ' Water samples were collected from each purged well using new disposable plastic bailers Each ' water sample was transferred into 40-m1 VOA vials containing 0 5 ml 18% hydrochloric acid as a sample preservative,and into 1-liter glass amber bottles without a preservative After collection,the samples were properly labeled,placed in a chilled container and transported under chain-of-custody ' to McCampbell Analytical, Inc The samples were analyzed for • TPH-ag in accordance with EPA Methods 5030/8015M, ' 0 BTEX with MTBE in accordance with EPA Method 602/8020, and 0 MTBE, TBA, D1PE, ETBE, and TAME in accordance with EPA Method 8260B I ' Advanced GeaEnvironmentai,Inc r