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CLOSURE REQUEST REPORT Section No 3 0 Former American Forest Products Company 07/31/01 2801 West Lane Page 3-3 Stockton,California of the site, in the opposite direction of the groundwater flow An additional survey was conducted in January 2001 to identify wells within a 2,000-foot radius of the site that have been installed since the initial survey This survey was based on a review of Water Well Drillers Reports at the California Division of Water Resources in Sacramento, California, (CDWR) With the exception of groundwater monitoring wells, no new wells appear to have been installed since 1988 3.3 SOIL ANALYTICAL DATA Soil samples have been collected at the site and analyzed for parameters including TPHd, TPH-gasoline (TPHg), benzene, toluene, ethylbenzene, and xylenes (BTEX), lead, and polycyclic aromatic hydrocarbons (PAHs) Maximum reported analytical results for these parameters have been summarized in the following table The results reported above are maximum concentrations in soil remaining at the site, following remedial excavation in 1990 Maximum Residential Detection Depth PRG' Constituent (m k ) Location Date (feet) (m ) TPHd(historic) 23,000 EES-6 6120/90 22 not defined TPHd(most recent) 18,000 DMW-6 12/15/98 25 not defined TPH not detected — — — not defined Benzene not detected — — — 065 Toluene 0 081 SB-20 5/3195 21 520 Eth lbenzene not detected 230 Xylenes 22 AFP-012-5 6/20190 3 210 Lead 190 P-19A 6124185 05 400 VOCs not detected — -- — —_ SVOCs Naphthalene 40 SB-1-10A 5/88 15 56 2-Methylnaphthalene 130 B-13 6/87 15 not defined P rene 1 8 SB-13-20 5/88 20 2,300 i U S Environmental Protection Agency(EPA),2000 Region 9 Preliminary Remediation Goals(PRGs) 2 Sample EES-6 was a confirmation sample collected at the base of the waste oil UST excavation,prior to refilling and capping (Dames&Moore 1992b) 3 Sample AFP- 12 collected in the area of the former underground fuel pipeline mg/kg = milligrams per kilogram SVOC = semivolatile organic compound TPHd = total petroleum hydrocarbon as diesel TPHg = total petroleum hydrocarbon as gasoline UST = underground storage tank A complete summary of all available soil analytical results, including samples collected at locations that were subsequently excavated in 1990 and 1991, are compiled in Table 3 Vertical profiles of TPHd are shown in Figures 5 and 6, and the areal extent of TPHd concentrations in soil at depths of 10, 15, 20, 25, 30 and 35 feet following soil remediation are shown in Figures 9 through 14 Review of soil analytical data indicates that residual TPHd impacts are located at depths of 10 to 30 feet bgs, where TPHd has been reported at a maximum concentration of 23,000 milligrams per kilogram (mg/kg) TPHd concentrations decrease by one to two orders of magnitude between 20 to 30 feet bgs, and below 30 feet bgs, TPHd impacts appear to be almost entirely absent (Figure 14) This vertical trend K 1840i91afp\afp_c1osure_rpt doc