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1.0 EXECUTIVE SUMMARY CRC Environmental Risk Management, Inc. (CRC) conducted a Phase 11 Environmental Assessment and Subsurface Investigation at the request of American Savings Bank (ASB) of Irvine, California. The environmental assessment was performed at the Lighthouse Village School building located at 222 North El Dorado Street, in the City of Stockton, San Joaquin County, California, on October 4, 1995. The subject property was formerly an ASB branch. From 1917 to at least 1953, the subject property was used for auto- related businesses, such as auto supplies and storage facilities, auto electrical service !' station and garage facilities with associated gas, oil and tire services. The existing building was built in 1961 as a banking facility. The purpose of the investigation was ' to determine whether the soil and groundwater at the subject property have been impacted by past operations of auto-related businesses and to assess whether potential offsite sources of contamination may have impacted the groundwater underneath the site. ` Prior to conducting subsurface exploration and soil sampling, a geophysical survey using electromagnetic (EM) and ground penetrating radar (GPR) methods was performed to ' clear the boring locations from underground utilities and to determine whether there are underground storage tanks (USTs) onsite. Six (6) borings were drilled and soil samples were collected for analysis. Three (3) of the soil borings located in the parking lot were ' drilled to 25 feet below ground surface (bgs). One soil boring in the parking lot was drilled to 35 feet bgs. Two (2) soil borings located in the basement of the building were hand-augered to 15 feet below the basement floor. In addition to the soil borings, CRC drilled two (2) borings to groundwater and converted these borings to monitoring wells i MW2 and MW3 to total depths of 41 feet and 46 feet bgs, respectively. Soil samples were collected in all borings at 5-foot intervals, starting at the 5-foot depth. The soil samples were field-screened using a Photo Ionization Detector (PID). Soil samples from each boring with the highest PID readings were analyzed for Total Petroleum Hydrocarbons (TPH) as gasoline and diesel and for Volatile Organic Compounds (VOCs). The monitoring wells were developed, purged and groundwater samples were collected and analyzed for TPH and VOCs. Water in the existing monitoring well MW1, installed by Clayton Environmental in 1991, was also purged, sampled and analyzed. ' All three (3) monitoring wells were surveyed to obtain groundwater table elevations which were used for calculating the groundwater gradient and determining the flow direction. The groundwater flow was determined to be southeasterly at depths of 27 to 28 feet bgs. The laboratory analytical results indicate that TPH as motor oil was detected in soil at 57 milligrams per kilogram (mg/kg) in boring B3 at 10 feet bgs and 880 mg/kg in boring B6 at 5 feet below the basement floor, which is approximately 8 to 9 feet bgs. TPH as diesel was also detected in soil at a concentration of 1,400 mg/kg in boring B6 at 5 feet bgs. TPH as gasoline was detected at 2.0 mg/kg and 5.3 mg/kg at the 5-foot depth in MW2 and in boring B6, respectively. TPH as diesel and VOCs related to gasoline or ' diesel were not detected in the soil in monitoring wells MW 1 and MW2. Only trace levels of TPH as diesel and gasoline were found in groundwater in monitoring wells CRC Environmental Risk Management,Inc, Project 0 2100.250-2 American Savings Bank 222 North El Dorado Street November 3. 1995 Stockton,California i b.