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CVvATc A S S O C I A T E S I N C hydrocarbons as diesel (TPHd) and MTBE The groundwater sample from boring SB3 also contained detectable concentrations of benzene, ethylbenzene, and xylenes In January 2004, ATC personnel supervised the advancement of soil borings MW1, MW2, and MW3 at the site to depths of approximately 65 feet bgs to evaluate groundwater for the presence of petroleum hydrocarbons and to determine the gradient direction and magnitude The borings were completed as monitoring wells Petroleum hydrocarbons were not detected in the groundwater samples collected from wells MW 1, MW2, or MW3 Field activities and analytical results are detailed in ATC's Summary Report of Subsurface Investigation, dated June 24, 2004 GROUNDWATER ELEVATION V A 4J�V6'� Water level measurements were collected from wells MW 1 through MW3 on July 9, 2004 Water levels ranged from X59 23 to 59 91 feet below the tops of the well casing elevations, representing an average irk si'n he water table elevation of approximately 7 97 feet since April 2004 The water level 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 July 9, 2004 was 0 0015 feet per foot (or approximately 7 9 feet per mile) and the gradient direction was to the sou.thw t� A summary of groundwater monitoring data is presented in Table 1 • SAMPLING ACTIVITIES On July 9, 2004, groundwater samples were collected by ATC personnel from monitoring wells MW1 through MW3 The locations of the monitoring wells are shown on Figure 2 Prior to collection of the groundwater samples, the depth to water in MW1 through MW3 was measured and pH, electrical conductivity, and temperature were measured and turbidity was visually observed in groundwater purged from the monitoring wells 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 shown in Attachment 1 The groundwater samples collected from the wells were submitted to State certified Argon Laboratories (Environmental Laboratory Accreditation Program Certification No 2119) for chemical analyses of TPHg and TPHd utilizing EPA Method 8015M, benzene, toluene, ethylbenzene, and xylenes (BTEX) utilizing EPA Method 8020, MTBE, ethyl tertiary butyl ether (ETBE), di-isopropyl ether (DIPS), tertiary amyl methyl ether (TAME), ethyl dibromi-de (EDB), 1,2-dichloroethane (1,2-DCA), TBA, Methanol and Ethanol utilizing EPA Method 8260B ANALYTICAL RESULTS Groundwater samples collected from wells MW1, MW2, and MW3 did not contain • concentrations of TPHg, TPHd, BTEX constituents, or fuel oxygenates at or above the laboratory reporting limits Analytical results for groundwater samples are summarized xn Table 2 Laboratory data sheets and chain-of-custody documentation are contained in Attachment 2 s 12687413QR-2004 doe 2