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itAAT� <br /> 1, A <br /> Mr Chuck Carmel <br /> February 14, 1994 <br /> Page 2 <br /> polyvinyl chloride bailer After purging, each well was sampled using a teflon bailer that was <br /> steam-cleaned between uses Field data sheets and chain-of-custody forms are included in <br /> Exhibit A <br /> All groundwater samples were analyzed for total petroleum hydrocarbons as gasoline (TPH-G) <br /> and benzene, toluene, ethylbenzene, and xylenes (BTEX) by U S Environmental Protection <br /> Agency (EPA) Methods 5030/8020/DHS LUFT <br /> Quarterly Monitoring Results and Discussion <br /> The general groundwater flow across the site is to the south-southwest under a hydraulic <br /> gradient of approximately 0 003 Water level data are listed in Table 1 Table 2 shows past <br /> and present hydraulic gradients and groundwater flow directions Figure 1 illustrates <br /> groundwater contours and the groundwater flow direction Well W-2B was not used for <br /> contouring, as this well is completed in a deeper zone than the other wells Well W-2A was <br /> not used in contouring because this well contained only a small amount of water that likely <br /> has collected in the end cap and is not representative of the water table surface <br /> The current southwest flow direction and gradient of 0 003 are within the ranges previously <br /> reported On August 23, 1993, the depth to water ranged from 66 30 feet to 69 12 feet <br /> Water levels in the monitoring wells decreased an average of 3 87 feet between May 25, 1993, <br /> and August 23, 1993 <br /> Current and historical analytical results are summarized in Table 3 The complete laboratory <br /> reports for the quarterly sampling are presented in Exhibit A BTEX and TPH-G were not <br /> detected in any of the samples, the detection limits for the BTEX constituents and TPH-G are <br /> 0 5 and 50 pg/l, respectively <br /> Status of Site Remediation <br /> This section provides a description of the remediation system and discusses the effectiveness <br /> of the remediation system operation <br /> Description. The remediation system at ARCO Station 434 consists of a groundwater <br /> extraction and treatment system (GWETS) and soil vapor extraction and treatment system <br /> ($VETS) The GWETS consists of one groundwater extraction well (E-1) with a designed <br /> pumping capacity of 1 gallon per minute (gpm) Treatment of the extracted groundwater is <br /> Use or disclosure of data contained on this sheet is subject to the restriction specified at the beginning of this <br /> document 748AREPORTMAUG93 QTR RPT <br />