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- I rJ Site Background Information : Quick N Save # 1 Page 2of9 i UNDERGROUND STORAGE TANK REMOVAL On 21 October 1999 , three USTs and associated piping and dispenser islands were removed from the site by Stockton Service Station Equipment Company (SSSEC) of Stockton , California . Approximately 150 cubic yards of hydrocarbon-impacted soil were i removed and stockpiled during excavation of the USTs . Nine samples were collected beneath the USTs , six samples were collected beneath the dispenser area and two laboratory-composited soil samples were collected from the excavated stockpiled soil . � I Methyl tertiary butyl ether (MTBE ), tertiary butanol (TBA) , tertiary-amyl methyl ether (TAME ) were detected in each of the soil samples collected from the site . Total petroleum hydrocarbons quantified as gasoline (TPH-g) were detected at concentrations as high as 3 , 849 mg/kg beneath the western end of the center UST location . Volatile aromatics -� including benzene , toluene, ethylbenzene and xylenes (BTEX) were detected at concentrations as high as 29 mg/kg from the same sample location . SOIL EXCAVATION r- On 20 April 2000 , approximately 175 cubic yards of petroleum hydrocarbon-impacted soil were excavated from the former UST area . Excavation was performed by SSSEC . The highest concentrations of petroleum hydrocarbons, TPH-g and fuel additives were f_J detected near the eastern end of the center UST (sample EN- 16' ). Fuel oxygenating compounds, including MTBE , TBA and TAME , were detected in each of the soil samples collected from the site at concentrations as high as 11 , 000 mg/kg . TPH-g were detected at concentrations up to 12 , 000 mg/kg beneath the western end of the center UST location . BTEX was detected at concentrations up to 1 , 800 mg/kg (total xylenes). PREVIOUS SITE ASSESSMENTS Soil Boring Advancements - August 2003 On 05 and 06 August 2003 , four soil probe borings (131 through 134) were advanced to a —i total depth of 50 feet bsg utilizing a van-mounted Geoprobe 5400 direct-push probing unit equipped with 1 .254nch diameter probing rods . Two boringswere advanced east and west, respectively, of the former UST excavation . The third boring was advanced north of the former UST excavation while the fourth boring was advanced east of the dispenser islands . TPH-g , MTBE , and BTEX compounds were detected in soil samples analyzed from all four - borings . TPH-g was detected in soil samples at maximum concentrations of 21 , 000 mg/kg in boring 131 at 35 feet bsg . MTBE was detected in soil samples at maximum I_J Advanced GeoEnvironmental, Inc.