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' SE 1�51y85URFIICG INVESMATON RESULTS RUVRT ofarlo,Stockton,California Selected soil samples were delivered u _ Hoer chain-Of-custody, to a state- certified analytical laboratory for analysis of concentration of: a) total purgeable petroleum hydrocarbons (TPPH) as gasoline; b) benzere, toluene, ethyibenzene, total xylenes (RTEX); c th len y e dibromide (EDS); and d) ethylene dichloride (EDG), In addition, the ritackpiled soil was sampled for organic lead. On July 11, 1991, the groundwater monitoring wells were developed, purged, and sampled. � i The groundwater samples were delivered under chain-of-custody,to a state- certified laboratory for analysis of concentrations of: a)TPPH as gasoline; F b) BTEX; c) EDB; d) EDC; and e) total lead. , The top-of-casing elevation of each well was surveyed by a sLrveor licensed in the State of California. c A The field and laboratory data was reviewed and a factual report of this investigation was prepared. 2.0�ACKGl30UM'OIMFORMATIOIV `F 2.1 Site ©escrfptTon i The subject site is located between South El Dorado Avenue and Center Street in the City ' r of Stockton, San Joaquin County, California (f=igure 1). The site is situated in a I �` commercial/residential/light industrial area of southern Stockton. The site is bound on j the north by East 2nd Street, on the east by South El Dorado Avenue, on the south by k3 a car wash facility, and on the west by Center Street. c i t e The Exxon service station is presently an active station. The store retails regular-leaded, regular-unleaded, and extra-unleaded gasolines. The station facilities ties include a building, � k three dispenser islands, and three underground storage tanks (UST) with associated E Product Piping. The three USTs are located immediately south of the dispenser islands on the southern half of the site. The type of construction and the installation dates of the � USTs are unknown. Figure 2 shows the location of the site's aboveground and underground features. Table i summarizes the tank inventory at the site. 2.2 Previous Investigation On February 5, 1991, a ground penetrating radar (GPR) survey was performed by =' NORCAL Geophysical Consultants, inc. (NORCAL), of Petaluma, California. The survey was performed in the area of the existing.--UST basin_to locate_-existing-underground- —----- ----- _ _ -- --- ----- -- facilities-far-avoidance-durin driliin - !� g. Upon completion of the GPR survey, two.soil 1 borings were drilled on February 22, 1990, at an angle of 30 degrees from Lvertical, ji� s 91-0448.RPf -