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Page 4 Tracy Tire Fire Celeste Temple, Project Officer near the well head without purging. Groundwater samples were collected directly into the sample containers, which were preserved as required. The sample containers were then chilled, capped, sealed, and processed for shipment to the laboratory for analysis. Volatile organic analysis (VOA)vials were filled first to minimize agitation of the sample. The VOA vials were inverted and checked for air bubbles to ensure zero headspace in the vials. A duplicate sample and a field blank were collected during each sampling event. The groundwater samples were submitted to a laboratory of APPL. Inc. in Fresno for definitive analysis of the following contaminants of concern: • Volatile Organic Compounds using EPA Method 524.2; • Semi-Volatile Organic Compounds using EPA Method 525.2; • Phenols using EPA Method 604; and ... . • Metals usitT PA Method 6010B. _:N' A_ Validated, groundwater analytical results are summarized in the attached table. Results shown in the table are shaded for those chemicals listed in the document entitled Rings of Fire prepared by the California Office of State Fire Marshall. Those chemicals are commonly identified toxins associated with tire fires. EPA Region 9 Preliminary Remediation Goals(PRGs)and California Primary Maximum Contaminant Levels (MCLS) were used as action levels. The California Secondary MCL (SMCL) was used for zinc, because there is no Primary 11V1CL for zinc. The analytical results were non-detectable for the contaminants of concern, except for the following: • Chromium in each of the samples collected from 30010 South MacArthur Road, Teichert Gravel Company, and 8952 West Palmquist; • Lead in the sample collected from RMC Lone Star Gravel Company (first event only): and • Zinc in the sample collected from 8952 West Palmquist. Of the detectable results, only the lead concentration of 10.7 ug1L in the groundwater sample collected from the RMC Lone Star Gravel Company well exceeded an action level. However, lead was not detected in the sample collected from this well during the second sampling event. CONCLUSIONS Based on the review of the available information, the following conclusions have been drawn with respect to the migration of contain inants from the site: • The hydraulic conductivity of the silts that predominate in the shallow subsurface is ITTzur30.799 wpd