SITE INFORMATION AND CORRESPONDENCE_FILE 2

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Site Background Information: Chapin Brothers Investments, Inc. Page 2 of 19 UST REMOVALS In August 1993, one 550-gallon waste oil UST, two 4,000-gallon gasoline USTs and two 8,000-gallon gasoline USTs were removed from the site. The tanks were removed from the north- central portion of the property. During removal,three additional 1,000-gallon USTs were discovered near the western portion of the property. These tanks were apparently abandoned in place;however, it is our understanding that the San Joaquin County-Environmental Health Department(EHD)has no record of the abandonment. Soil samples collected at the time of the tank removals indicated the presence of low petroleum hydrocarbon impacted soil at the site. TPH-g were detected at 70 mg/kg at 13 feet bsg and toluene, ethylbenzene and total xylene concentrations were at 4 mg/kg, 17 mg/kg and 74 mg/kg,respectively. Lower concentrations were detected in the stockpiled soil piles. ASSESSMENT OF HYDROCARBON IMPACTED SOIL AND GROUND WATER In 1993, four soil borings were drilled at the site. Two borings were located on-site and two were located off-site. Three of the borings were completed as 2-inch diameter groundwater monitoring wells. Well MW-2 was installed north of MW-1,across Monte Diablo Avenue;MW-3 was installed west of MW-1,across Buena Vista Avenue;MW-4 was installed south of MW-1,near the northeast corner of the on-site structure. The fourth boring was completed as a 4-inch diameter vapor extraction well(VW-1)near the center of the site. Low concentrations of petroleum hydrocarbons were detected in soil samples from MW-3,MW-4 and VW-1.No hydrocarbons were detected in soil samples from MW-2. Eight additional soil borings were drilled in March 1994,B6 to B 13. Seven of the eight soil borings were drilled off-site, south and southwest of the site. The data indicated that impacted soil extends approximately 180 to 200 feet off-site to the southwest;however,most of the off-site impacted soil contains very low concentrations of petroleum hydrocarbons. AQUIFER TESTING AND ANALYSIS A pump test was performed at the site by SEACOR. Groundwater was extracted from MW-1 and drawdown was measured in three surrounding wells. The test duration was approximately 24 hours. SEACOR concluded in the PAR that drawdown data collected during the pump test indicated that the pumping from MW-1 has little influence at the site. Therefore, a pump and treat system of ground water remediation would likely be ineffective at the site. Complete pump test data was included in the PAR. Advanced GeoEnvironmental,Inc.