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Protection Agency (EPA) Toxicity Characteristic Leaching Procedure (TCLP) method was not detected. Total Hg concentrations ranged from less than 0.06 to 9.1 mg/kg, soluble mercury using STLC ranged from non-detect to 0.046 mg/L. An additional investigation was performed in Parcel 3 in conjunction with identification of TPH contaminated soil. Wallace Kuhl (2005) advanced eight (8) soil boreholes (Boreholes SB1 through SB8) to a depth of up to 30 feet bgs. Petroleum hydrocarbon odor and discoloration was identified in Borehole SB5. Soil samples were collected at five (5) foot intervals and analyzed for TPH, VOCs, SVOCs, polycyclic aromatic hydrocarbons (PAHs), pH and California Assessment Manual (CAM) 17 Metals. Confirmation soil samples were collected in conjunction with excavation of TPH contaminated soil. East sidewall samples indicated remaining concentrations of TPHd up to 40 mg/kg and TPHo up to 90 mg/kg. Total petroleum hydrocarbons as kerosene (TPHk) was not detected. West sidewall samples indicated remaining concentrations of TPHd up to 6,600 mg/kg; TPHo and TPHk were not detected. Bottom sidewall samples indicated remaining concentrations of TPHd up to 1400 mg/kg and TPHo up to 3.1 mg/kg; TPHk was not detected. The north and south sidewall samples contained TPHd up to 440 mg/kg and 230 mg/kg, respectively. Two (2) groundwater samples were collected from the excavation. These samples contained TPHd at 0.0027 and 0.0036 micrograms per liter (ug/L). Additionally, VOCs, arsenic, barium and fluorine were identified. Copies of soil analytical laboratory data collected during previous investigations by Treadwell & Rollo (1999 and 2001) and Wallace Kuhl (2005) are provided in Appendix F. 1.6.2 CONTAMINANT DISTRIBUTION IN GROUNDWATER In Parcel 24, groundwater samples have been collected from Wells MW-3 and MW-7. At Parcel 3 groundwater samples were taken from Hydropunch samples 3GW-1, 3GW-1A, 3GW-2 and 3GW-2A; Wells 3MW-1/1R and MW-36; and Boreholes DP-8, DP-9 and DP-21.4 Recent sampling (3 June 2004) at Parcel 24 has identified TPHd and TPHo at concentrations of 1,400 ug/L in Well MW-3, 610 ug/L in Well MW-7, 370 ug/L in Well MW-3 and 230 ug/L in Well MW-7. Neither gasoline nor benzene was detected recently, although gasoline petroleum hydrocarbons have been historically detected at 51.5 ug/L in Well MW-3 and 54 ug/L in Well MW-7. Other COCs including n-propylbenzene, MTBE and TBA were reported at below their respective MDLs for Wells MW-3 and MW-7 during the 5th of May 2003 sampling event. The metal As was detected in Well MW-3 at 160 ug/L (18 February 2004) and in Well MW-7 at 31 ug/L (17 February 2004). The metal Pb was below the MDL of 3 ug/L in Well MW-3 and detected at a concentration of 3.5 ug/L in Well MW-7 (17 February 2004). In Parcel 3, recent (18 February 2004) groundwater sampling from Wells 3MW-1R and MW- 36 did not identify TPHg, TPHd or TPHo above their MDLs. Past samplings identified TPHg, TPHd, TPHo, and BTEX in groundwater. This included TPHg at 0.07 mg/L and BTEX at 0.95 ug/L, 4.9 ug/L, 1.5 ug/L and 7.5 ug/L, respectively (Treadwell & Rollo, 1999). In 2001, TPHd was detected in Hydropunch samples 3GW-1 at 530 ug/L, 3GW-1A at 110 ug/L, 3GW-2 at 110 ug/L and 3GW-2A at 180 ug/L. In August of 2003, TPHg was identified in Well 3MW-1R at a 4 sECOR, 2004, Table 4, 5 and 7, July 28 Golden State Environmental, Inc. - 7 - Los Angeles, San Diego and Houston Revised Work Plan — Soil and GW Characterization July 2006