Laserfiche WebLink
• Closure Report - Chevron Station#9-1848 <br /> januaEZ 18, 1999 <br /> a GSI witnessed the removal of one 5,000-gallon and two 10,000-gallon gasoline <br /> underground storage tanks(USTs)and associated product lines,a 1,000-gallon waste-oil <br /> UST, four hydraulic hoists and 15-gallon hydraulic fluid tank, a grease trap, and an oil- <br /> water separator Soil samples were collected beneath all subsurface facilities removed <br /> Five soil samples were also collected from the base of the new gasoline UST pit <br /> Total Petroleum Hydrocarbons as gasoline (TPHg) and benzene were detected in ail six <br /> of the soil samples collected at approximately 16 feet bgs from the former gasoline UST <br /> excavation TPHg and benzene were also detected in the product line soil samples <br /> collected from a depth of 4 5 feet bgs Five soil samples collected at a depth of 18 feet <br /> bgs from the new gasoline UST excavation contained detectable TPHg and benzene <br /> concentrations The soil sample with the highest concentration of TPHg (2,100 ppm) <br /> was collected from the southern product line trench at a depth of 4 5 feet bgs The <br /> highest benzene concentration (2 4 ppm) was detected in the soil sample collected at <br /> depth of 16 feet bgs beneath the southern end of the 5,000-gallon gasoline UST <br /> Low concentrations of TPHg were detected in the two soil samples from the waste oil <br /> UST pit, and benzene was detected in one of these samples Total Petroleum <br /> Hydrocarbons as oil (TPHo) were not detected in any of the soil samples except for one <br /> collected from the western hydraulic lift. Data from this investigation are presented <br /> in GSI's Tank Replacement Observation Report, dated August 23, 1991 Soil Chemical <br /> Analytical data are included in Appendix A-1, and soil sample Iocations are shown on <br /> Figures 3 <br /> e To evaluate the extent of hydrocarbon impact to soil and groundwater beneath the site, <br /> three groundwater monitoring wells (C-1 through C-3) were installed by GSI on <br /> July 23, 1991 Eight soil samples were submitted for analysis of TPHg and benzene, <br /> toluene, ethylbenzene, and total xylenes (BTEX) The soil samples collected from well <br /> boring C-2, located in the vicinity of the former waste-oil UST, were also analyzed for <br /> TPHd and TPHo Six of the eight soil samples did not contain detectable TPHg or <br /> benzene concentrations TPHd or TPHo were not detected in any of the soil samples <br /> analyzed However, TPHg were detected in two samples collected at depths of 19 5 <br /> feet (well boring C-1) and 16 teet (well boring G2) bgs at concentrations of 2 0 and 13 <br /> ppm, respectively Data from this investigation are presented in GSI's Well Installation <br /> Report, dated September 5, 1991 Soil chemical analytical data are presented in <br /> Appendix A-2, and well boring locations are shown on Figure 3 <br /> v To further define soil and groundwater conditions beneath the site, GR advanced four <br /> exploratory soil borings on August 23, 1997 The four borings were advanced to a <br /> • 346392 02-cl 2 <br />