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CV\/ATC J A S S 0 C I A T E S I N C petroleum hydrocarbons and to determine the gradient direction and magnitude The borings were completed as monitoring wells Analytical data indicated that soil samples collected from boring MW2 contained detectable concentrations of petroleum hydrocarbons Petroleum hydrocarbons were also detected in a groundwater sample collected from well MW2 A groundwater sample collected from MW3 contained very low concentrations of only a few of the requested analytes Petroleum hydrocarbons were not detected in the groundwater sample collected from MW4 Field activities and analytical results are detailed in ATC's Summary Report of Additional Subsurface Investigation, dated February 24, 2000 In December 2001, soil-boring VEWI was advanced to approximately 35 feet bgs, and borings VEW2 and VEW3 were advanced to approximately 45 feet bgs Borings MW5, MW6, and MW7 were advanced to approximately 65 feet bgs Soil borings VEWI, VEW2, and VEW3 were completed as 2-inch diameter vapor extraction wells and soil borings MWS, MW6, and MW7 were completed as 2-inch diameter groundwater monitoring wells Boring CPT1 was advanced to approximately 100 feet bgs utilizing a truck-mounted cone penetration test (CPT) rig A soil vapor extraction pilot test was conducted which yielded a radius of influence (ROI) of approximately 30 feet Approximately 2 64 pounds of total petroleum hydrocarbons quantified as gasoline (TPHg), benzene, toluene, ethylbenzene, and xylenes (BTEX) were removed during the vapor extraction pilot test Soil vapor extraction appeared to be a viable method for remediating TPHg and BTEX impacted soil at the site Field activities and analytical results are detailed in ATC's Remedial Investigation/Feasibility Study, dated November 19,2002 GROUNDWATER ELEVATION Water level measurements were collected from wells MW1 through MW7 on October 20, 2003 Water elevations ranged from a high of—32 67 to a low of—32 81 representing an average decrease in water table elevation of 2 48 feet since July 2003 The water Ievel data were used to develop a groundwater elevation contour map (Figure 3) Review of the groundwater elevation contour map (Figure 3) indicates that the hydraulic gradient beneath the site on October 20, 2003 is relatively flat and the gradient direction varies across the site A summary of groundwater monitoring data is presented in Table 1 SAMPLING ACTIVITIES On October 20, 2003, groundwater samples were collected by ATC personnel from monitoring wells MWI through MW7 The locations of the monitoring wells are shown on Figure 2 Prior to collection of the groundwater samples, the depth to water, pH, electrical conductivity, and temperature were measured in each monitoring well and recorded A minimum of three well casing volumes was purged from each well prior to sampling The wells were allowed to recover and a sample was collected from each well using a disposable bailer_ Groundwater well purge and sample logs are contained in Attachment I The groundwater samples collected from the wells were submitted to State certified Argon Laboratories (ELAP Cert No 2359) for chemical analyses of TPHg, total petroleum hydrocarbons I ( quantified as diesel (TPHd), and total petroleum hydrocarbons quantified as kerosene (TPHk) w 162577AQA-2003 doc