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~, <br />Y <br />Ms. Connie Davis/Aggregate Industries - F Street January 2002 QMR <br />Project Number 1001018 Pl~Rl~Ci~N <br />February 27, 2002 <br />Page 3 <br />approximately 0.002 to 0.02 for the spill area based on the January 2002 groundwater <br />elevation data. <br />The regional groundwater flow direction and hydraulic gradients estimated for January 2002 <br />are similar to previous observations. The local groundwater flow direction and hydraulic <br />gradients estimated for January 2002 are different than previous observations and appear to <br />be attributable to the lack of irrigation in the vicinity of the site and less dewatering being <br />performed at t:1e site in January 2002. It should be noted that local geohydrologic <br />characteristics such as flow direction and gradient may change due to variations in <br />precipitation and recharge or other conditions not evident at the time of field exploration. <br />3. GROUNDWATER QUALITY RESULTS <br />Information collected during the January 2002 quarterly sampling events relative to <br />groundwater quality at the site is summarized below. That information includes <br />temperature, electrical conductance and pH measurements; dissolved oxygen (DO) <br />measurements; and laboratory results. <br />3.1 Quarterly Monitoring Field Data <br />Groundwater temperature, electrical conductance and pH measurements were performed on <br />January 29, 2002 during purging of the wells prior to collecting groundwater samples for <br />laboratory analyses. Measurements were recorded during the removal of water from the <br />wells. The wells were considered purged when temperature, electrical conductance and pH <br />measurements stabilized to within ten (10) percent for three (3) consecutive measurements <br />and a minimum of three (3) well volumes were removed from the well. Purge water was <br />discharged on site. <br />DO measurements were also performed on January 29, 2002. DO monitoring results are <br />summarized in Table 2 and on Figure 4 which are attached to this report. As seen from <br />Table 2 and Figure 4, DO concentrations ranging from approximately 1.0 to 2.1 milligrams <br />per liter (mg/L) were observed at the site during the January 2002 sampling event. <br />3.2 Quarterly Monitoring Laboratory Data <br />Groundwater samples were collected on 7anuary 29, 2002 by Paragon from wells MW-1 <br />through MW-5 and EW-1. The samples were placed in glass vials with Teflon septa and <br />transported under standard Paragon chain-of-custody procedures to Technology Laboratory, <br />Inc. (TLI) for BTEX and TEPH analyses. Laboratory results for groundwater samples <br />