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1 <br /> kn KLEINFELDER <br /> 4. GROUNDWATER SAMPLING <br /> Groundwater samples were collected during the Third Quarter 2004 sampling event on August <br /> 25, 2004 The groundwater samples were collected from four onsite monitoring wells MW-1, <br />' MW-2, MW-3, and MW-4 at the General Mills facility(Plate 1) <br />' 4 1 MEASUREMENT OF WATER LEVELS <br /> In order to evaluate the groundwater gradient at the time of sampling, water level measurements <br /> were made in each of the four monitoring wells at the beginning of the sampling event prior to <br /> purging and sampling of the wells The depth-to-water was measured in each well according to <br />' the protocol described in Appendix A, Section A-4 The depth-to-water measurements were <br /> converted to groundwater elevations with respect to a local benchmark by subtracting the depth <br /> to water measurements from the surveyed casing elevations <br /> The groundwater elevations were then used to calculate the direction of groundwater flow and <br /> gradient This information was then used to evaluate which wells represent upgradient and <br />' which wells represent downgradient water conditions <br /> The depths to water at the four wells, measuring from the north side of the nm of the PVC pipe, <br /> ranged from 40 20 feet below top of casing (approximate ground surface) at MW-4 to 41 18 feet <br /> in MW-3 Groundwater elevations during the third quarter 2004 sampling event ranged from a <br /> high of -0 10 feet at MW-4 to a low of -1 50 feet at MW-2 (Table 1) Groundwater flow <br /> direction was calculated to the southwest at a gradient of approximately 0 004 ft/ft during the <br /> third quarter 2004 (Plate 2) <br /> r <br /> 4.2 COLLECTION OF GROUNDWATER SAMPLES <br />' A total of fourgr oundwater samples were collected from monitoring wells MW-1 through MW-4 <br /> during the Third Quarter 2004 sampling event conducted in August 2004 The wells were <br /> rpurged and sampled using disposable bailers and as generally described in Kleinfelder's Protocol <br /> (Appendix A) A transparent disposable bailer was partially submerged into the groundwater <br /> prior to purging each monitoring well to assess the groundwater for a potential sheen and/or, <br /> floating product No petroleum odor, floating product or sheen was observed in perimeter <br /> monitoring wells MW-2, MW-3, and MW-4 A strong petroleum odor, sheen, and approximately <br /> I 1/5 inch (0 02 feet) of floating product was observed in the groundwater purged from MW-1 <br /> during this sampling event Copies of the monitoring well sampling logs for the Third Quarter <br /> 2004 are included in Appendix B <br />' Purge water from the monitoring wells was stored on site in labeled 55-gallon drums pending <br /> chemical analysis and disposal by the client <br /> 28209 T03/ST04R1402/DH 1v Page 6 of 11 <br />' ©2004,Kieinfelder,Inc October 20,2004 <br />