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i <br /> -� N= <br /> C L_ EARWATER <br /> G R O U P, I N C <br /> ' <br /> vicinity of existing USTs and fuel dispensers Results of the investigation are <br /> presented in Clearwater's Preliminary Site Assessment Report, dated October <br /> ' 11, 1995 <br /> ' 3.0 FIELD ACTIVITIES <br /> ' 3.1 Groundwater Gauging <br /> On December 14, 1995 Clearwater measured the depth to groundwater in <br /> t BMW-1 and BMW-2 and Geocon measured the depth to water in five <br /> monitoring wells associated with the FDIC site On the same day, the casing <br /> elevations of all seven wells were surveyed to the nearest 0 01 foot by a <br /> ' professional surveyor Measurements were made relative to City of Lodi <br /> benchmark #516 and mean sea level (MSL) <br /> ' Table 1 presents the survey data for BMW-1, BMW-2, and MW-1 through <br /> MW-5 The table also includes the groundwater gauging data collected by <br /> Clearwater and Geocon on December 14, 1995 <br /> 3.2 Groundwater n Pur id Sampling <br /> Purging anm P g <br /> ' Prior to sampling BMW-1 and BMW-2, each well was purged using a PVC <br /> bailer that had been thoroughly washed in an Alconox solution and double- <br /> rinsed in distilled water The bailer was decontaminated prior to purging <br /> ' each well An equipment blank was collected from the decontaminated PVC <br /> bailer after purging BMW-2 (prior to purging BMW-1) <br /> ' At least three well casing volumes of groundwater were removed from each <br /> well while field personnel monitored temperature, conductivity, and pH <br /> ' Well purging information is presented in Appendix A <br /> After the water levels in BMW-1 and BMW-2 had recovered to at least 80% of <br /> ' the pre-purge levels, samples were collected using dedicated disposable <br /> polyethylene sampling bailers Groundwater samples were transferred to <br /> laboratory-supplied 40 milliliter volatile organic analyses (VOA) vials <br />' containing hydrochloric_acid as a preservative and unpreserved 1 liter amber <br /> bottles <br /> Clearwater obtained five sets of groundwater samples from Geocon, the <br /> samples were collected in laboratory containers (as described above) provided <br /> by Clearwater Geocon purged the five monitoring wells by removing <br /> C-115 4Qtr 95 2/96 2 <br />