ARCHIVED REPORTS XR0005971 - Laserfiche WebLink

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central Stockton. The location of the site is shown in Figure 1, • and the site facilities are shown in Figure 2 . The site is located in a residential/commercial area, and the local topography is flat. A Chevron gasoline station was formerly located across Franklin Street from the site, but has been demolished and is presently undergoing assessment of soil and groundwater contamination resulting from .activities at that site. Groundwater monitoring data at that site indicate that groundwater flow is to the northeast, toward the Kwikee Foods site, and monitoring wells have been drilled in Franklin Street near the Kwikee Foods property line (Figure 2 ) . 2 .2 Previous Work A groundwater monitoring well was installed near the dispenser island in 1990. This well was originally labelled MW--1 , but has been renamed KF-3 in this investigation. It is our understanding that Geological Technics performed routine groundwater monitoring of this well in April 1990 . Total petroleum hydrocarbons in the gasoline range (TPH-g) were detected at a concentration of 81, 000 µg/l (ppb) , and benzene was detected at a concentration of 2, 107 ppb. Toulene, ethylbenzene, and xylene were also detected at, elevated levels . , � I Subsequently, EHD requested further assessment of the extent of the plume of contaminated groundwater, but no work was performed until monitoring wells KF-1 and KF-2 were installed by Soils Exploration • Service -under the supervision of Upgradient in December , 1994. ' neither well encountered significant soil contamination, but gasoline and aromatic hydrocarbons were detection above reporting limits in groundwater samples from both wells . Gasoline was also detected in KF-3 . Groundwater elevation data indicated that ' groundwater flow was to the east. Upgradient recommended that monitoring continue on a quarterly basis , and scheduled the next monitoring event for March, 1995 . 3 .0 MONITORING PROCEDURES Monitoring took place on March 20, 1994 . The wells were opened and the depth to groundwater was measured, using a Solinst water level meter. A two-stage submersible pump was used to purge the wells of standing water, which was deposited in a 55--gallon drum on the east side of the property. , During purging, , the temperature, pH, and conductivity of the water were measured at 5-gallon intervals with a Corning Checkmate meter until these parameters stabilized ( see Appendix A) . To prevent cross-contamination, the pump was washed in a TSP solution between wells . After purging, samples were collected with a disposable plastic bailer and placed in 40-m1 vials . The vials were labelled and logged, placed in a cooled ice chest, and shipped to McCampbell Analytical for analysis . The chain-of-custody form and laboratory report are` included in Appendix B. . 2