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Canepa's Car Wash 248 East Park Street,Stockton,California First Quarter Groundwater Monitoring Report,January 2004 Page 2 of 5 Summary of January 2004 Quarterly Groundwater Monitoring Results Field Activit Number of monitor wells 7 Number of monitor wells sampled 7 Date(s) monitored 01/28/04 Site Hydrology Average depth to groundwater below Average increase(+)/decrease(-)m monitor well measuring points 27 88 feet depths to groundwater since last sampling -0 39 foot The lowest(deepest)groundwater Approximate groundwater flow direction Northeast elevation has consistently been measured at monitor well MW-2 Groundwater Contamination Wells containing free product None Wells with petroleum hydrocarbon odor 2 noted Number of wells with benzene Number of wells with benzene concentrations below the benzene MCL 4 concentrations at or above the benzene 3 MCL Range in concentrations Benzene(lig/L) <0 5—7,600 BTEX Toluene(li / ) <0 5—3,100 Nature of contamination Ethyl benzene(4g/L) <0 5— 1,700 TPH-G Total xylenes(pg/L) <1 0—5,500 TPH-G(mg/L) <0 05—48 • FIELD OBSERVATIONS All monitor wells were purged using a clean, single-use, polypropylene, disposable bailer Approximately three well casing volumes of water were purged from each well The purged water from each well was placed in 55-gallon drums and left on site pending laboratory analytical results No sheen or separate phase petroleum was noted in field inspection samples from the wells Slight and strong petroleum odors were noted to the groundwater inspection samples from wells MW-2 and MW-5, respectively GROUNDWATER ELEVATIONS AND GRADIENT The static water level in each well was measured to the nearest 0 01 foot with a battery-operated, flat tape, water-level meter The groundwater monitoring field forms and groundwater measurement field form are included in Attachment C The groundwater table has been above the top of all well screens since the August 1996 monitoring event The average groundwater elevation measured during the January 2004 monitoring event was 0 39 foot higher than measured in November 2003 The groundwater elevation contours for the current monitoring event indicate a groundwater gradient generally toward the northeast, consistent with previously reported gradient information �� CONDOR