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hn KLEINFELDER Soil samples were collected at 5 foot intervals beginning at a depth of 5 feet for logging purposes and potential chemical analysis. Soil samples submitted for analyses were collected at depths of five and ten feet below ground surface (bgs) in borings B1/1-IP-1 through B6/HP-6. One soil sample was submitted from boring B7 at an approximate depth of 15 feet bgs. Each of the borings were advanced to a maximum depth of approximately 21 feet. Groundwater samples were collected in Borings 131 through B6, using a Hydropunch IITm sampling device. Groundwater was encountered at a depth of approximately 10 feet bgs. A total of thirteen soil samples and six groundwater samples were submitted from borings B1/HP-1 through B7 (No groundwater sample was collected from boring B7). The soil and groundwater samples were analyzed for one or more of the following: • Volatile Organics by EPA Method 8260 • Semi-Volatiles Organics by EPA Method 8270 • Fuel Fingerprint by EPA Method 8015M • CAM 17 Metals by EPA Methods Based on the data obtained during our assessment, the following conclusions and recommendations have been formulated: 1. In the southwest portion of the site a concentration of 2.4 µg/L benzene was detected in groundwater from boring B6/HP-6. This concentration exceeds the Maximum Contaminant Level (MCL) listed in Title 22 of California Code of Regulations §64431. Unidentified Extractable Hydrocarbons (UEH) and phenanthrene (constituent of crude oil) were also detected in groundwater at concentrations of 190 mg/L and 110 µg/L, respectively, from boring B6/HP-6. Although Kleinfelder does not know of a MCL for petroleum hydrocarbons ranges, the UEH concentrations detected are relatively high. The source and extent of the impacted groundwater is unknown. 2. Toluene was detected in a soil sample obtained from boring B6/HP-6 at a depth of 10 feet at a concentration of 0.11 mg/kg. The concentration detected is very low. However, the concentration exists in soil near groundwater. The source and extent of the toluene in soil is unknown. 3. Unidentified Extractable Hydrocarbons (UEH) were also detected in groundwater in boring B1/YIP-I located in the northwestern portion of the site at 340 µg/L. However UEH was not detected in two soil samples analyzed from the same boring. Boring B1/HP-1 is located near the northwest corner of the subject site adjacent to the Santa Fe Pacific Petroleum Pipeline. The source or extent of UEH in the groundwater in that area is unknown. 4. It is Kleinfelder's opinion that concentrations of metals detected in soils and groundwater during this assessment at the proposed Tracy Multimodal Station reflect background Iconcentrations rather than contaminants. 20-4054-01.E01/2018R299 Page 2 of 15 © 1998,Kleinfelder,Inc. May 8, 1998 r