ARCHIVED REPORTS_XR0007449 CASE 1

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KLEINFELDER 4 GROUNDWATER SAMPLING ' Groundwater samples were collected during the second quarter sampling event on rune 12, 2003 The groundwater samples were collected from four onsite monitoring wells MW-1 through MW-4 at the General Mills facility(Plate 1) ' 41 MEASUREMENT OF WATER LEVELS In order to evaluate the groundwater gradient at the time of sampling, water level measurements were made in each of the four monitoring wells at the beginning of the sampling event prior to purging and sampling of the wells The depth-to-water was measured in each well according to the protocol described in Appendix A, Section A-4 The depth-to-water measurements were ' converted to groundwater elevations with respect to a local benchmark by subtracting the depth to water measurements from the surveyed casing elevations The resulting groundwater elevations were used to calculate the direction of groundwater flow and gradient This information was then used to evaluate which wells represent upgradient and which wells represent downgradient water conditions The depths to water at the four wells, measuring from the north side of the rim of the PVC pipe, ranged from 37 38 feet below top of casing (approximate ground surface) at MW-4 to 38 29 feet in MW-3 Groundwater elevations during the second quarter 2003 sampling event ranged from a high of 2 72 feet at MW-4 to a low of 1 48 feet at MW-2 (Table 1) Groundwater flow direction ' was calculated approximately to the southwest at a gradient of approximately 0 004 ft/ft during the second quarter 2003 (Plate 2) 4 2 COLLECTION OF GROUNDWATER SAMPLES ' A total of four groundwater samples were collected from monitoring wells MW-1 through MW-4 during the second quarterly sampling event conducted in June 2003 The wells were purged and ' sampled using disposable bailers and as generally described in Appendix A A transparent disposable bailer was partially submerged into the groundwater prior to purging each monitoring well to assess the groundwater for a potential sheen and/or floating product No petroleum odor, ' floating product or sheen was observed in perimeter monitoring wells MW-2, MW-3, and MW-4 A strong petroleum odor, sheen, and approximately one half inch of floating product was observed in the groundwater purged from MW-1 dunng this sampling event Copies of the monitoring well sampling logs for the second quarter 2003 are included in Appendix B Purge water from the monitoring wells was stored on site in labeled 55-gallon drums pending chemical analysis and disposal by the client 28209 T03/ST03R1312 Page 6 of 1 1 0 2003 Klemfelder, Inc September 22, 2003