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LFR Levine-Fricke Comparison of the data with preliminary remediation goals (PRGs) indicates that arsenic is present in all the soil samples collected at concentrations exceeding the PRG. As of the year 2000, the PRG for arsenic was 2.7 milligrams per kilogram(mg/kg)and was used by START to evaluate the data. However, it should be noted that the arsenic concentrations reported in background samples(greater than 4 mg/kg)were also above the reference PRG concentration(see Appendix E). Concentrations of metals other than arsenic were reported below their respective PRGs. The U.S. EPA also compared the metals analysis data to the U.S. EPA's soil screening levels(SSLs)to assess the potential for metals to leach and affect groundwater. Arsenic, antimony(estimated value), cadmium, total chromium, and zinc in surface soil samples exceeded their respective SSLs. Only one soil sample(TT-T1-2-2)contained a significant(>4,000µg/kg) concentrations of VOCs and only two soil samples (TT-T1-2-1 and TT-T3-1-1) contained significant(>1,000 mg/kg)concentrations of oil and grease (see Appendix E). VOCs and SVOCs were not detected above PRGs or SSLs in soil samples collected from the Site. To characterize the soil for disposal, selected soil samples were analyzed using the soluble threshold limit concentration(STLC) and toxicity characteristic leaching procedure(TCLP). Eight of the 36 soil samples contained concentrations of metals that indicated potential for leachability. Seven metals from the eight soil samples were analyzed using the STLC and TCLP methods. Zinc was the only metal of the seven analyzed that significantly exceeded the STLC (250 mg/1). No metals exceeded the representative action level for the TCLP. Surficial soil within the burn areas is therefore classified as a Class I non-Resource Conservation and Recovery Act(-RCRA) hazardous waste. 2.2 Groundwater START installed four groundwater monitoring wells from November 29 through December 11, 2001. The wells range in depth from 70 to 100 feet and all have a 20- foot screen interval with 0.010-inch slots. Figure 4 shows the locations of the monitoring wells. At the time of installation, the groundwater depth was approximately 70 feet bgs. Based on groundwater elevations collected during December 2001, the groundwater appears to be flowing to the northwest with a gradient of approximately 0.001 foot per foot(ft/ft). Groundwater samples were collected from the four on-site groundwater monitoring wells(MW-1, MW-2, MW-3, and MW-4)on December 13, 2001. Groundwater samples collected from wells MW-1, MW-2, and MW-4 contained higher concentrations of aluminum, arsenic, barium, chromium, cobalt, iron, lead, magnesium, manganese, nickel, potassium, silver, vanadium, and zinc than the sample collected from the upgradient well(MW-3). In the four wells, several metals were detected at concentrations exceeding their respective maximum contaminant levels (MCLS). With the exception of one VOC (methyl tertiary-butyl ether [MtBE])reported Page 4 Final_RAP_Tracy_9.18.03(final).doc