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+ M 11 <br /> Canepa's Car Wash <br /> 248 Past Park Street,Stockton,California <br /> Second Quarter Groundwater Momtonng Report,May 2004 <br /> Page 2 of 5 <br /> Summary of May 2004 Quarterly Groundwater Monitoring Results <br /> Field Activit <br /> Number of monitor wells 7 Number of monitor wells sampled 7 <br /> Date(s) monitored 05/10/04 <br /> Site Hydrology <br /> Average depth to groundwater below Average increase(+)/decrease (—) in <br /> monitor well measuring points 27 30 feet depths to groundwater since last sam lm —0 5$ foot <br /> The lowest(deepest)groundwater <br /> Approximate groundwater flow direction Northeast elevation has consistently been measured <br /> at monitor well MW-2 <br /> Groundwater Contamination <br /> Wells containing free product None Wells with petroleum hydrocarbon odor 2 <br /> noted <br /> Number of wells with benzene Number of wells with benzene <br /> concentrations below the benzene MCL 5 concentrations at or above the benzene 2 <br /> MCL <br /> Range in concentrations <br /> Benzene(µg/L.) <0 5—9,300 <br /> BTEX Toluene(µgJL) <0 5—3,300 <br /> Nature of contamination Ethyl benzene(pg/L) <0 5-- 1,900 <br /> TPH-G Total xylenes(lig/L) <1 0—6,000 <br /> TPH-G(mg/L) <0 05--50 <br /> • FIELD OBSERVATIONS <br /> All monitor wells were purged using a clean, single-use, polypropylene, disposable bailer Approximately <br /> three well casing volumes of water were purged from each well The purged water from each well was <br /> placed in 55-gallon drums and left on site pending laboratory analytical results No sheen or separate <br /> phase petroleum was noted in field inspection samples from the wells Moderate and strong petroleum <br /> odors were noted in the groundwater inspection samples from wells MW-2 and MW-5, respectively <br /> GROUNDWATER ELEVATIONS AND GRADIENT <br /> The static water level in each well was measured to the nearest 0 01 foot with a battery-operated, flat tape, <br /> water-level meter The groundwater monitoring field forms and groundwater measurement field form are <br /> included in Attachment C The groundwater table has been above the top of all well screens since the <br /> August 1996 monitoring event The average groundwater elevation measured during the May 2004 <br /> monitoring event was 0 58 foot higher than measured in January 2004 The groundwater elevation <br /> contours for the current monitoring event indicate a groundwater gradient generally toward the northeast, <br /> consistent with previously reported gradient information <br /> 4Mp� CONDOR <br />