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Quik Stop Market No. 132 Project No.349132-31 September 19, I990 Page 2 ` FIELD INVESTIGATION Ex lora�v. Dri1]in d oil 1� ' Exceltwh installed four groundwater monitoring wells and drilled five soil tori gs at the locations shown on Figure 2. The locations were selected in an attempt to define the limits of hydrocarbon concentrations in the soil and determine if groundwater beneath the site had been affected. The soil borings were drilled to groundwater while the borings for the monitoring wells were drilled approximately 10 feet below first encountered water(total depth 26.5 to 30 feet), The borings were drilled with a truck-mounted B-61 or B-53 drill rig using hollow-stem augers. The augers and other tools used were steam-cleaned before t=� use and between borings to minimize the possibility of cross-contamination. During the drilling, the soil sampler was scrubbed and washed with trisodium phosphate(TSP) and rinsed in deionized water. Relatively undisturbed soil samples were collected at 5-foot 4 depth intervals using a Cplifornia split spoon sampler equipped with three internal brass tubes,each 6 inches long and 2 inches in diameter. pler was advanced 18 inches into undis,lirbed soils with a 140-pound hammer. All soil cuttings from the drilling were placed on niostic and left at the site. After recovery from the borehole,the loriiermost sample liner at each sample location above grolndwater was preserved for chemical analysis. All soil samples collecQabove the i a saturated zone were analyzed for total petroleum hydrocarbons as gasoline (TPHG); benzene,toluene,ethyl benzene,and total xylenes(BTEX);and total lead. The soils in the remaining brass liners were used for 1n in oses and then tested with a portable '7 Photoionization detector ID !1g g P - (PID)for the presence of volatile hydrocarbons, y r The samples retained for chemical analysis were preserved in the following manner. Both ends of the liner were covered with aluminum foil and a plastic end cap. It was then labeled with a unique sample number and pertinent sample information;placed in a plastic ziploc t= bag, entered onto a chat i-of-custody form,and packed in a chilled ice chest. The r' was transported AnametAx Laboratory. sam,�e An Exceltech geologist prepared a log of the subsurface conditions encounterfi> ,r drilling and classified the soils according to the Unified Soil Clas ideation System and Munsell Soil Color Charts. All log sheets were reviewed by a registered_engineering eoloi ' ed-engineering- -geologist. Exceltechs soil sampling '' -- protocol is in Appendix A. � . E r nw i n WllQnstruction t� After the soll sampling was completed,Exceltech installed monitoring wells.in the four deepest exploratory borings. Exceltech constructed the monitoring wells in accordance 1 with all permit requirements of San Joaquin County Public Health Services.