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EXECUTIVE SUMMARY The objectives of this phase of environmental corrective action were to continue to monitor the plume of impacted groundwater at the water table, further define the stratigraphy of groundwater-bearing soils beneath the water table, and evaluate the vertical extent of impacted groundwater To achieve these project objectives, Ramage Environmental monitored and sampled the monitoring well network, and supervised the drilling of two CPT borings and collecting of discrete groundwater samples from permeable intervals beneath the water table Soils encountered during cone penetration testing generally consisted of a massive sequence of clay and silt soils interrupted by intervals of sand and gravelly sand Sandy intervals were observed in CPT-1 at approximately 29 to 35 feet, 57 to 62 feet, and 105 to 121 feet bgs, and in CPT-2 at approximately 28 to 32 feet, 54 to 57 feet, 113 to 119 feet, and 128 to 136 feet bgs Sandy soil intervals beneath the water table appear to be relatively continuous between the two CPT locations 4n January 31, 2002, the static depth-to-groundwater ranged from 39 95 feet below ground surface (bgs) in MW-7 to 41 47 feet bgs in MW-1 The corresponding groundwater surface elevation ranged from a high of 21 86 feet below mean sea level (msl) at MW-6 to a low of 22 59 feet below msl at MW-2 The resulting groundwater surface appears as an irregular plane dipping to the east-southeast at a gradient of approximately 0 0025 foot/foot Between November 1, 2001 and January 31, 2002, the groundwater surface rose an average of 0 88 feet, and the groundwater flow direction and gradient remained relatively constant Consistent with previous results, gasoline compounds were only detected in MW-2 and MW-3 The highest concentrations of gasoline hydrocarbons (140,000 µg/l of TPH-as-gasoline, 4,200 µg11 of benzene, 37,000 µg11 of toluene, 3,300 µg/l of ethylbenzene, 22,000 pg/l of xylenes, and ' 500 jig/[ of 1,2-DCA) were detected at MW-2 MTBE was not detected in any of the groundwater samples The plume of impacted groundwater at the water table appears to be defined and stable Concentrations of gasoline compounds in first groundwater beneath the site continue to decline, probably in response to source removal and natural attenuation Gasoline compounds were also detected in the discrete groundwater samples collected at approximately 60 feet bgs at CPT-1A and CPT-2, 105 feet bgs at CPT-1A, and 115 feet bgs at CPT-2 The sample collected at 130 feet bgs at CPT-2 did not contain gasoline compounds MTBE was not detected in any of the discrete groundwater samples As such, the lateral extent of impacted groundwater in these two intervals remains undefined to the southeast (downgradient) of the site Vertically, the extent of impacted groundwater beneath the site is undefined Southeast of the site, the vertical extent of impacted groundwater is defined to a depth of less than 130 feet Based on these conclusions, Ramage Environmental recommends that a work plan be prepared to further define the extent of impacted groundwater beneath the water table, and to test the feasibility of soil and groundwater remedial options Quarterly groundwater monitoring should also be continued 4