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Ms Vicky McCartney Project No 880-040 1A <br /> December 8, 2003 <br /> Page 3 <br /> On May 23, 2002, two monitoring wells (MW-4 and MW-5) were installed The two <br /> well bonngs were drilled to a total depth of 25 feet bgs One deep boring was advanced <br /> adjacent to well MW-1 to define the vertical extent of MtBE in soil and groundwater at <br /> the site This boring was continuously cored from 30 feet bgs to the total depth of <br /> 54 feet bgs to provide a complete hthologic description of subsurface conditions <br /> A dual phase extraction (DPE) was conducted from June 10 through 15, 2002 The DPE <br /> test was conducted by simultaneously extracting soil vapor and groundwater from well <br /> MW-1 Based on the results of the DPE test, DPE appeared to be an effective remedial <br /> alternative to remove MtBE and other oxygenates from soil and groundwater, and <br /> control off-site migration <br /> GROUNDWATER MONITORING DATA <br /> Groundwater monitoring of wells MW-1 through MW-3 have been conducted since <br /> September 2000, and wells MW-4 and MW-5 since July 2002 In the most recent <br /> monitoring event performed on July 21, 2003, Total Petroleum Hydrocarbons as <br /> gasoline (TPHg), or benzene, toluene, ethylbenzene, and xylenes (BTEX) were not <br /> detected in wells MW-2, MW-4, and MW-5 TPHg were reported in wells MW-1 and <br /> MW-3 at concentrations of 4,400 and 160 micrograms per liter (ug/1), respectively <br /> Benzene was only reported in well MW-1 at a concentration of 640 ug/l Di-isopropyl <br /> ether (DIPE) or ethyl tert-butyl ether (ETBE) were not detected during this event, tert- <br /> amyl methyl ether (TAME) was not detected in wells MW-3 or MW-5, and tert-butyl <br /> alcohol (TBA) was not detected in well MW-2 through MW-4 TAME was reported in <br /> wells MW-1 (11 ug/l), MW-2 (37 ug/l), and MW-4 (250 ug/1), and TBA was reported in <br /> wells MW-1 (8,800 ug/l) and MW-5 (41,000 ug/l) MtBE was reported in all wells <br /> ranging from 230 ug/l (well MW-1) to 14,000 ug/l (well MW-4) <br /> During the July 21, 2003 event, depth to groundwater averaged 14 19 feet below top of <br /> casing Ground%&r flow was to the northeast at a gradient of approximately 0 001, <br /> which is consistent with historical data <br /> f <br /> l <br /> N 1sacDP12003TrJM81880040 1 A 3aa doc <br />