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F <br /> I <br /> BeBrown ann C lffWeli <br /> . ..._ <br /> JAN A 6 1992 <br /> December 31. 1991 ENVIRONMENTAL HEALTH <br /> PERMIT/SERVICES <br /> Mr. Chuck Carmei <br /> ARCO Products Company <br /> Post Office Box 5811 017-5330-03/1 <br /> San Mateo, California 94402 <br /> Subject: Quarterly Report for ARCO Station 434, 501 Kettletnan Lane. <br /> Lodi, California: Site Code 1341 <br /> Dear Mr. Carmel: <br /> This report presents water levels and analytical results of groundwater sampling performed <br /> at ARCO Products Company (ARCO) Station 434, located at 501 Kettleman Lane in Lodi, <br /> California on October 22, 23, and 24, 1991. 'There are six on-site monitoring wells (W-IA, <br /> W-2,W-2A,W-2B,W-3,and W-9)and eight off-site monitoring wells(W-4,W-5,W-6,W-7, <br /> W-g,W-10,W-11, ar-d W-12) (Figure 1). All monitoring wells were sampled except W-2A <br /> and W-4, due to lack of water and slow recharge in these wells. <br /> Field and Analytical Methods <br /> Brown and Caldwell personnei measured depth-to-water levels, supervised purging of each <br /> well, and collected groundwater samples at the site. Refer to Exhibit A for detailed field <br /> methods description. <br /> All groundwater samples were analyzed for to=,ai petroleum hydrocarbons as gasoline(TPH-G) <br /> and benzene,ethylbenzene, toluene, and xylenes (BETX) by U.S. Environmental Protection <br /> Agency (EPA)Methods 5030/modified 801518020. <br /> Results <br /> The general groundwater flow direction is to the south. The general approximate hydraulic <br /> gradient is 0.003. Groundwater elevation contours for October 1991 are shown on ;=igure 1. <br /> Table 1 presents the water-level elevations and Table 2 presents th.e past and present hydraulic <br /> - - -- --- -- s and 3- are <br /> gradients and groundwater 17ow-drrecsions-for-the-subJectsiteFigure - - -- -- - <br /> - <br /> hydrographs showing groundwater elevations for all monitoring wells from April 1987 to <br /> t October 1991. <br /> Analytical results of groundwater samples ,ire summarized in Table 3, along: with previous <br /> results. The complete laboratory report for the October 1991 sampling is presented in <br /> Exhibit B. Fieure a shows BEVY and TPH-G concentrations. Figure ~ is a benzene <br /> isoconcentration map. <br /> `380JtFJ?ORl'SOCT7l�7[Rl'tM <br />