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Y3 4.2.1 Site 2 ' No PHCs were detected in the soil or groundwater samples collected from the two borings Additionally, no discolored soils or petroleum product odors were detected and no organic vapors were detected by the PID in either of the borings. Table 2 indicates that total lead was detected at concentrations ranging from 7.8 to 12 mg/kg in the four soil samples collected at the site. No lead was detected in the groundwater samples tLead was used as a gasoline additive for many years in the form of tetraethyl lead. According to the American Society for Testing and Materials (ASTM) Guidance Document for Risk-Based ' Corrective Action Applied at Petroleum Release Sites (ASTM E1739-95), tetraethyl lead decomposes to inorganic lead in dilute aqueous solutions and in contact with other environmental media. It remains as organic lead in free gasoline product, however, no free product was observed at the site. Since lead was detected in soil samples which contained no organic compounds (petroleum hydrocarbons), it is reasoned that the lead is in an inorganic state US EPA Region IX Preliminary Remediation Goals (May 1998) for inorganic lead in ' soil are 130 mg/kg for residential soils and 1,000 mg/kg for industrial soils The lead concentrations found at the site are much lower than these remediation goals. Published background data for lead m the western United States has an arithmetic mean of 20 mg/kg with a concentration range from less than 10 to 700 mg/kg (based on "Element Concentrations in Soils and Other Surficial Materials of the Conternimous United States", U S Geological Survey Professional Paper 1270, 1984). Since the soil samples were collected in areas peripheral, to the former excavation and no PHCs were detected in these soils, it is reasoned that: the lead concentrations detected are background levels for the area. In addition, lead concentration in all samples are far below total threshold limit concentration (TTLC) value ' of 1,000 mg/kg The TTLC value, per Title 22 of the California Code of Regulations (CCR), is the concentration of a solubilized, extractable and nonextractable bioaccumulative or persistent toxic substance which, if equaled or exceeded in a waste, renders the waste hazardous. ' 4.2.2 Site 3 No PHCs were detected in the uppermost soil samples collected from 10 to 11 feet bgs, or ' in the two lowermost samples collected at 35 and 40 feet bgs, in any of the three borings PHCs in soils were first detected at 16 feet bgs in boring B3-2, and at 20 feet bgs in borings B3-1 and B3-3 (Table 3, Figure 4) The highest levels of PHCs in soils were detected in the ' sample collected from 15.5 to 16.0 feet bgs in boring B3-2. This sample contained 2,100 mg/kg TPHg and 8 4 mg/kg benzene (Table 3) ' 9 98117\ rvx FM=US 1K xfz BOYAJIAN & ROSS, INC ' Environmental Scientists & Eng3neers