WORK PLANS - Laserfiche WebLink

Home Browse Search

Site Background Information: Ernie's General Store Page 2 of 4 are on low fan terraces. The estimated depth to ground water at the property is 30 feet to 35 feet below surface grade(bsg), based on the map entitled Lines of Equal Depth to Groundwater Spring 1996 published by the San Joaquin County Flood Control District and Water Conservation District(FCD&WCD). However, based on quarterly ground water monitoring events conducted at the site beginning in August 2003, ground water is currently encountered at approximately 60 feet to 70 feet bsg and flows consistently north-northeast. Ground water is considered to be of beneficial use and is used for domestic, industrial and commercial purposes. UNDERGROUND STORAGE TANK REMOVAL On 05 January 1999, one 12,000-gallon fuel UST and two 10,000-gallon fuel USTs were removed from the southeast end of the site. The approximate locations of the former USTs are shown on Figure 2.During the UST removals,a total of seven soil samples(1 T through 3T),two from beneath each 10,000-gallon UST and three from beneath the 12,000-gallon UST, were collected from the floor of the excavation. A total of nine soil samples, one from beneath each product dispenser (D1 through D5)and one beneath every 20 linear feet of product piping(P 1 through P4),were collected. Additionally, four two-part composite samples (SP-1 through SP-4) were collected from the soil stockpile. Soil samples were collected from beneath the former USTs at depths of 14 feet to 16 feet bsg, beneath the product dispensers at 3 feet bsg,beneath the product piping at depths of 3.5 feet to 4 feet bsg, and from the stockpiled soil excavated from the UST excavation. Soil samples were analyzed for total petroleum hydrocarbons quantified as gasoline (TPH-g), volatile aromatic compounds benzene,toluene, ethylbenzene, and total xylenes (BTEX), and fuel oxygenates di-isopropyl ether (DIPE),ethyl tertiary-butyl ether(ETBE), methyl tertiary-butyl ether(MTBE), tertiary-amyl methyl ether(TAME), and tertiary-butyl alcoholl (TBA). TPH-g was detected in three of the seven soil samples collected from beneath the former USTs at concentrations of 1.0 milligrams per kilogram (mg/kg) (1 TC-15.5), 2,300 mg/kg(2TW-15.5), and 1.1 mg/kg(3TW-15.5). TPH-g was also detected in one of the five soil samples collected beneath the product dispensers at a concentration of 17 mg/kg (D2-3) and in one of the four samples from the stockpiled soil at a concentration of 1.0 mg/kg(SP-1). Toluene,ethylbenzene,and total xylenes were detected in UST sample 2TW-15.5 at concentrations of 1.1 mg/kg, 8.4 mg/kg, and 70 mg/kg, respectively. Toluene and total xylenes were detected in soil sample P44 at concentrations of 0.005 mg/kg and 0.016 mg/kg,respectively. MTBE was detected in fifteen of the twenty soil samples collected during the UST removals at concentrations as high as 17 mg/kg(D2-3).Every soil sample collected from beneath the dispensers contained detectable concentrations of MTBE. TBA was detected in soil sample 1TE-15.5 at a Advanced GeoEnvironmental,Inc.