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" Mr Kyle Christie February 7, 1996 Page 2 benzene, toluene, ethylbenzene, and xylenes (BTEX), methyl-tent-butyl ether (MTBE), and total petroleum hydrocarbons as gasoline (TPH-G) by U S Environmental Protection Agency (EPA) Methods 503018020, and 8015 Modified Field data sheets and chain-of-custody documentation are included in Exhibit A Results and Discussion The general groundwater flow direction beneath the site on November 17, 1995 was to the south southeast under a hydraulic gradient of approximately 0 002 (Figure 1) Wells W-2A and W-2B are not used for contouring because they are screened in different zones than the other wells Since groundwater monitoring began in 1988, the general groundwater flow direction has ranged from southwest to southeast at this site The hydraulic gradient measured this quarter is within the range of previously reported gradients Depth-to-water on November 17, 1995 ranged from 6191 feet below the top of the well casing (TOC) in well W-8 to 64 93 feet below TOC in well W-9 Water-level elevations in the monitoring wells increased an average of 0 92 feet since the last quarterly monitoring event (August 10, 1995) Monitoring wells W-4 and W-2A were dry this quarter Summaries of depth-to-water measurements and calculated groundwater elevations are presented in Table 1 Table 2 lists past and present groundwater flow directions and hydraulic gradients for this site . BTEX, MTBE, and TPH-G were not detected in any of the sampled wells (W-1 A, W-2, W-3, W-5, and W-9) Analytical results of groundwater samples are summarized in Table 3 The complete laboratory report for the sampling event is presented in Exhibit A Figure 2 shows TPH-G and BTEX results for this sampling event Status of Site Remediation This section provides a description of the remediation system and discusses the effectiveness of the remediation system operation Description. The remediation system at ARCO Facility 434 consists of a soil vapor extraction and treatment system (SVETS) A ground water extraction and treatment system (GWETS) which was formerly in use at the site, was shut down on April 19, 1993, due to nondetectable concentrations of hydrocarbons in the groundwater The GAC vessels have been removed for use at another ARCO facility, and the effluent piping from the GWETS to the industrial sewer was disconnected The connection point to the industrial sewer was capped to prevent any accidental releases Because the GWETS operation has been terminated, Industrial Waste Discharge Permit No 151, that allowed discharge of the treated groundwater to the City of Lodi industrial sewer, has been suspended . Use or disclosure of data continued on this sheet is subject to the restriction specified at the beginning of this document 2065\REP0RTS`4TH45QTR DOC