FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

l Soil Boring Report — former Chevron Station #9-3232, Stockton CA July 27 1999 Soil Analytical Results Petroleum hydrocarbons were detected in soil samples from 5 of the 6 borings. TPHg and benzene were detected in soil from borings BH- 1 , BH- lA, BH-2, BH-3 , and BH-4. TPHg concentrations ranged from 1 .64 to 8,560 ppm . Benzene concentrations ranged from 0.0116 to 65 .8 ppm . Soil chemical analytical data are listed in Tables 1 and 2. WASTE DISPOSAL Soil cuttings generated during drilling activities were placed on and covered with plastic sheeting at the northwest corner of the site and a disposal confirmation sample SP 1 -A,B,C,D (Table 1 ) was collected. Approximately 5 yards of soil cuttings were removed from the site by Allwaste and taken to the BFI landfill in Livermore, California, for disposal on June 6, 1999 . DISCUSSION Concentrations of TPHg greater than 1 ,000 ppm were encountered in borings BH- 1 , BH- lA, BH- 2 and BH-3 (adjacent to the UST pit and eastern dispenser island) at depths up to 50 feet bgs. Concentrations then diminish significantly with depth toward the base of the borings (60-70 feet bgs) where TPHg concentrations are <10 ppm . Benzene concentrations exhibit a similar trend, diminishing to <0.2 ppm at the base of the borings. Except for the sample collected at 50 feet bgs in boring BH4, hydrocarbons were not detected in borings BH-4 or BH-5 . Fuel oxygenates, including MtBE, were not detected during this investigation. Soil samples previously collected during the installation of wells MW- 1 and MW-3 did not contain Petroleum Hydrocarbons. Together, these data indicate that hydrocarbon impact to soil beneath the site has been delineated to the north of the dispenser islands and east of the dispensers and UST pit. Soil impact remains undefined off site to the south and west. 346463 .04-2 4