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Jimco Truck Plaza Page 2 of 3 • Advancement of a boring approximately 105 feet southeast of MW-7, adjacent to the east side of the underground diesel piping; • Advancement of a boring adjacent to the north side of the above-ground storage tanks and east of where the underground diesel piping makes a ninety degree angle; • Advancement of a boring approximately 30 feet northwest of the oil/water separator; • Advancement of a boring approximately 60 feet due south of MW-6; • Advancement of a boring approximately 45 feet due north of MW-6; and • Advancement of two borings, one approximately 130 feet northeast of MW-6 and one approximately 130 feet southeast of MW-6. However, EHD believes these Geoprobee borings should be advanced to at least 60 feet below ground surface (bgs) instead of the proposed depth of 25 feet bgs. Although EHD concurs with Cambria's assessment that historical soil data demonstrate that most of the petroleum hydrocarbon impacted soil is detected above 25 feet bgs, there is a need to investigate soil lithology below the 30- to 35-foot total depth of the ten existing monitoring wells. Also, groundwater data collected quarterly from MW-1, MW-2, MW- 6, MW-8, and MW-9, screened at 10 to 30 feet bgs, and MW-10 screened at 15 to 35 feet bgs, as well as groundwater samples collected at 45 feet bgs in borehole B-17 and 60 feet bgs in B-18, all demonstrate that petroleum hydrocarbon impacted groundwater exists well below the 25-foot depth. Collecting grab groundwater samples at approximately 25 feet bgs would provide little additional information. EHD,believes the three proposed CPT borings are appropriately located as listed below: • Advancement of one CPT boring approximately 200 feet due west of MW9; • Advancement of one CPT boring approximately 10 feet northeast of MW-1; and • Advancement of one CPT boring approximately 10 feet due west of MW-6. Cambria proposes that the CPT borings be advanced to approximately 80 feet bgs. No technical justification was presented for terminating the borings at approximately 80 feet bgs and collecting grab groundwater samples at approximately 60 and 75 feet bgs; however, Cambria indicated that the borings might be advanced deeper if needed to I�