Laserfiche WebLink
I S E C O R <br /> IConceptual Site Model <br /> Chevron Service Station #9-6171 <br /> March 25, 2005 <br /> I Page 4 <br /> 3.0 SITE BACKGROUND AND CURRENT SITE CONDITIONS <br /> I <br /> 3.1 Current Site Conditions <br /> Chevron Service Station 9-6171 Is currently an operating service station It is located at <br /> 6633 Pacific Avenue (Township 2N, Range 6E, Section 21, Mt Diablo base and meridian) <br /> I in Stockton, CA (Figure 1) The site has been an active service station since the early <br /> 1980's Facilities onsite consist of a convenience store, three underground storage tanks <br /> (USTs), three pump islands, and ten active and two abandoned groundwater monitoring <br /> wells Former and current site features are shown in Figure 2 <br /> The following discussion provides a brief history of previous site investigations <br /> 32 Previous Investigations <br /> A summary of previous investigations is presented below Historical soil and groundwater <br /> analytical data tables are presented in Appendix A Historical boring logs are presented in <br /> Appendix B The data from Appendices A and B were used to construct representative <br /> geologic cross sections of the subsurface sediments at this site (Figures 3 and 4) <br /> Underground Storage Tank, Piping, and Island Removal — 1986 <br /> In December 1986 three USTs and two fuel islands were removed from the northeast <br /> corner of the property At this time, sod within the tank pit was sampled before the <br /> excavation was backfilled and new USTs were installed in the southwest corner of the <br /> property During this remodeling of the service station, the former 560-gallon capacity <br /> waste oil tank was replaced by a new 1,000-gallon capacity waste oil tank (WOT-1) <br /> Soil samples collected from in and around the tank pit during tank excavation were <br /> analyzed for petroleum hydrocarbons Total purgeable petroleum hydrocarbons reported <br /> as gasoline (TPHg) were detected in the northern portion of the tank pit at a maximum <br /> concentration of 84 parts per million (ppm) Benzene was detected at the southern end of <br /> the tank pit at a maximum concentration of 1 7 ppm Toluene, ethylbenzene, and total <br /> xylenes were not detected in any of the sod borings Based on the analytical results from <br /> the soil samples, the San Joaquin County Department of Environmental Health (SJCDEH) <br /> requested that a soil boring and monitoring well be installed within the area of the former <br /> tank pit <br /> IN IFlles\Projects\Chevronlftetadl##9-61711Sde Conceptual ModeRFINAL_CSM doc <br />