ARCHIVED REPORTS_XR0002148 - Laserfiche WebLink

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L lett ton Clayton Fnvironmental Consultants, Inc. was retain:d by Interland Corporation to supervises the excavation and aeration of petroleum hydiocarbon contaminated soil at 8715 W--t Grant Line Road in Tracy, California This projec► was authorized by Mr. Dor, Lewis, Interland vice president, by accepting Clayton's Proposal No 90-8- 117, dated May 20, 1990, and a supplement Proposal No 29531 00, dated August 20, 1990, with accompanying term. and conditions Mr Tom Ramsey of Fuel Oil Polishing was directly contracted by Interland to perform the soil excavation, aeration, and backfilling Work at the subject site began in January 1990 when Orchard Supply Hardware_ (7SH) retained Clayton to conduct a Phase I environmental assessment at the site This assessment was performed to conduct a due diligence environmental investigation at the site prior to purchase by OSH. rhe Phase I assessment revealed that an underground storage tank (UST) which contained gasoline was operated onsite and was removed in 1986. Subsequently, OSH retained Clayton to install three monitoring wells to sample and analyze soil and groundwater at the site Laboratory analysis of soil and groundwater detected gasoline and l and grease contamination in soil samples The maximum gasoline concentration Lound in the soil was 68 ppm and the maximum oil and grease concentration was 250 ppm Groundwater samples from all three monitonng wells onsite did not indicate contamination of groundwater. Depth to groundwater was measured to be between 8 and 10 feet. Based on the analytical results, Clayton recommended excavating and aerating the soil in and around the location of the removed gasoline tank Fuel Oil Polishing Company excavated about 1,650 cubic yards of soil from the vicinity of the UST. This soil was stockpiled in thin layers on plastic sheeting for aeration Soil samples were collected from the walls of the excavation pit to confirm satisfactory removal of contaminated soils Analysis showed that concentrations of gasoline, benzene, toluene, ethylene, and xylenes (BTEX), and oil and grease in the soils were below those acceptable to the San Joaquin County Public Health SerFices, Environmental Healti, Division (PHS/EHD - the supervisory agency) in the final excavation. Dunng excavation, a 500-gallon concrete septic tank was discovered Clayton obtained a permit for the removal of this tank The tank was removed on August 17, 1990. Analysis of soil samples collected from beneath the former location of the removed septic tank did not reveal any significant contamination Alter aeration of the excavated soil, eight composite: samples were collected at the direction pit PHS/E-1-1D anis analyzed for Total petroleum hydrocarbons (TPH) as gasoline, BTEX, and oil and grease. Laboratory analyses revealed the following: • Gasoline, benzene, e thylbenzene, and xylenes were not detected • Toluene was detected at Concentrations of between 21 parts per pillion (ppb) • and 220 ppb. -ir-