|
Chevron products Company 2
<br />Former Chevron Service Station 95775 301 West Kettleman Lane Lodi California March 30, 2000
<br />• The five former underground storage tanks (USTs), hydraulic hoists, dispenser islands, and
<br />associated product piping were removed on August 24, 1998, by Musco Excavators (Gettler-
<br />Ryan, Soil Sampling During Underground Storage Tank and Piping Removal, dated
<br />November 10, 1998) Soil samples were collected by Gettler-Ryan (G -R) beneath the USTs
<br />and product piping Low to nondetect concentrations of petroleum hydrocarbons were
<br />reported in soil samples collected below the waste oil UST, product lines, and hydraulic
<br />hoist Soil samples collected beneath the gasoline USTs contained concentrations of total
<br />petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, and methyl tertiary butyl
<br />ether (MtBE) up to14,000 mg/kg, 84 mg/kg, 1,500 mg/kg and 56 mg/kg, respectively, in the
<br />sample collected from 14-112 feet below ground surface (bgs) below the eastern end of the
<br />middle gasoline UST The area beneath the eastern end of the middle gasoline UST was
<br />excavated from 14-112 to 16 feet bgs, and a second soil sample was collected
<br />Concentrations of TPHg, toluene, and MtBE were reported as 880 mg/kg, 52 mg/kg, and 11
<br />mg/kg, respectively, benzene was reported as not detected in this sample
<br />On August 31, 1998, the area beneath the eastern end of the middle gasoline UST was over -
<br />excavated from 16 to 22-1/2 feet bgs Soil samples collected from the base and the eastern
<br />wail of the excavation were reported to contain concentrations of TPHg, benzene, and MtBE
<br />at 2,300 mg/kg, 4 1 mg/kg, and 330 mg/kg, respectively
<br />Between January 25 and January 27, 1999, five soil borings were drilled by V&W Drilling at
<br />the subject site, with four of the bonngs completed as monitoring wells (G -R, Monitoring
<br />Well Installation Report, dated June 2, 1999) The four monitoring wells (MW -1 through
<br />MW -4) were completed to 65 feet bgs Soil samples collected by G -R from the bonngs had
<br />reported concentrations of TPHg, benzene, MtBE, and ethyl tertiary butyl ether (ETBE) up to
<br />1,200 mg/kg, 0 81 mg/kg, 78 mg/kg, and 1 3 mg/kg, respectively Groundwater samples
<br />collected from the monitoring wells had reported concentrations of TPHg, benzene, MtBE,
<br />ETBE, and tertiary amyl methyl ether (TAME) up to 11,000 ug/l, 6,800 ug/1, 62,000 ug/l,
<br />2,400 ug/1, and 780 ug/l, respectively
<br />•
<br />In October of 1999, G -R continuously monitored the groundwater elevations at the site over
<br />a three-day period (G -R, Offsite Source Survey, dated November 2, 1999) The results of the
<br />study indicated that groundwater elevations fluctuate in daily cycles corresponding to the
<br />operation of nearby City of Lodi Municipal Well 12 (Well 12), located approximately 350
<br />feet southwest of the site
<br />Between December of 1999 and February of 2000, five additional monitoring wells (MW -
<br />5A, -6, -7, -8A, and MW -9 [now renamed as MW -9A]), four soil vapor extraction wells (VE -
<br />1 through VE -4), one groundwater extraction well (EX -1), and two soil bonngs (SB -2 and
<br />SB -3) were installed by V&W Drilling (G -R, Monitoring Well Installation Report, dated
<br />March 30, 2000) Soil samples collected from the borings were reported to contain
<br />concentrations of TPHg, benzene, and MtBE up to 1,740 mg/kg, 446 mg/kg, and 100 mg/kg,
<br />1Chevron1957751Aqu1fer test\Revised195775Aqutfertestrevised doe
<br />
|