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k'■ KLEINFELDER 1 EXECUTIVE SUMMARY This is a report of Kleinfelder's Limited Phase II Environmental Site Assessment conducted in the area of the proposed March Lane underpass at the Union Pacific Railroad in Stockton, California. Mr. Conrad Bridges of HDR retained Kleinfelder on behalf of the City of Stockton. The assessment was conducted after correspondence with Mr. Ray Deyto from the City of Stockton and Mr. Bridges, and is based upon Kleinfelder's proposal entitled "Proposal/Workplan/Cost Estimate, Temporary Groundwater Monitoring Well Installation, March Lane Undercrossing at Union Pacific Railroad, Stockton, California," dated April 8, 1998. Kleinfelder conducted this soil and groundwater assessment of the UPPR underpass to evaluate the potential presence of petroleum contaminants from potential off site sources. Soil and groundwater samples were collected during construction of the two temporary monitoring wells. The soil and groundwater samples were analyzed for petroleum constituents and total lead. During construction of the temporary wells soil samples were collected every five feet from ground surface: Twenty groundwater samples (ten from each boring EB-1/TW-1 and EB-2/TW- 2) were submitted under chain-of-custody procedures to Sequoia Analytical Laboratory of Sacramento, California. Eight of the soil samples were analyzed for petroleum constituents and/or total lead. No purgeable hydrocarbons as referenced to gas or benzene, toluene, ethylbenzene, or xylenes (BTEX) were detected in the soil samples submitted for analyses. Unidentified extractable hydrocarbons (UEHs) in the C„ to C40 range were detected in both borings, EB-1/TW-1 and EB- 2/TW-2, at a depth of 5-feet bgs at concentrations of 62.7 mg/kg and 13.5 mg/kg. Total lead was also detected at 30.7 nig/kg in the five foot soil sample collected from EB-1/TW-1. No other analytes were detected in the soil samples. The soils collected from the five foot interval were noted with a hydrocarbon-like odor and included the highest PID reading of 6.5 ppmv. Because this soil was noted with minor wood and slight discoloration, it is suspected to be till material. The depth interval range of the suspected fill material is estimated to be approximately 3 to 8 feet bgs. It is Kleinfelder's opinion that the contaminants (UEHs and total lead) found were likely imported and therefore probably not the result of nearby potential sources of contamination (i.e.: spills, leaks etc.). Two groundwater samples (one from each boring EB-1/TW-1 and EB-2/TW-2) and four water samples (trip and field blanks) were submitted under chain-of-custody procedures to Sequoia Analytical Laboratory of Sacramento, California. All six water samples were analyzed for petroleum constituents and/or total lead. The field and trip blanks were analyzed for purgeable petroleum constituents only. 20-3712-08.E01/201810 10 Page I o1`16 © 1998,Kleinfelder. Inc. hely 9, 1998