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• groundwater monitoring data (March, 1992) determined groundwater flow direction to the south A detailed discussion of the initial subsurface investigation can be found in RESNA's "Interim Problem Assessment Report, Soil and Groundwater Contamination, " dated June 8, 1992 In July 1994, a RESNA field geologist observed the drilling of four additional groundwater monitoring wells (MW4, MW5, MW6, and MW7) at the site to further characterize subsurface conditions Groundwater samples collected from these additional wells contained no detectable petroleum hydrocarbons A detailed discussion of the Phase 2 Subsurface Investigation can be found in RESNA's "Summary Report, July 1994 Investigation, " dated August 26, 1994 In a letter received from the PHS/EHO dated March 1995, permission was given to sample MW3 and MW4 and MW5, MW6 and MW7 on an alternating semi-annual basis MW1 and MW2 were to be sampled every quarter, conditions permitting GROUNDWATER MONITORING AND SAMPLING Smith Environmental personnel performed groundwater monitoring and sampling on August 17, 1995 Field work consisted of measuring the depth-to-water in wells MW1, MW2, MW3, • MW4, MW5, MW6, and MW7, using an electronic water/product interface probe to determine if free product was present, purging and sampling wells MW1, MW4, MW6 and MW7, and subjectively evaluating collected water samples for the presence of petroleum hydrocarbon constituents Static groundwater elevations were measured in each monitoring well on August 17, 1995 Groundwater exists at approximately 12 to 14 feet below grade A groundwater gradient map is presented in Figure 2 It depicts a westerly groundwater gradient of 0 0015 ft/ft or approximately 8 feet/mile Fluid level measurements indicated groundwater flow direction beneath the site during the third quarter was consistent with the last monitonng event Groundwater monitoring data are summarized in Table 1 On August 17, 1995 groundwater samples were collected from monitoring wells MW 1, MW4, MW6, and MW7 Samples were collected after stabilization of pH, electrical conductivity (EC), and temperature All wells monitored were purged and sampled according to Smith Environmental's Quality Assurance/Quality Control Pian on file with the PHS/EHD A minimum of four casing volumes of water were removed from each sampled well Purge water was contained in labeled DOT approved 55 gallon drums and stored on site pending laboratory analysis and proper disposal A dedicated disposable bailer was used to collect each water sample No sample was collected from well MW2 for Iaboratory analysis due to the presence of floating product Field parameters and purged volumes are shown on well purge logs included in Appendix I 1500914QUARTM3QR 1945 DOC SMITH