ARCHIVED REPORTS XR0005967 - Laserfiche WebLink

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2.0 INTRODUCTION Upgradient Environmental Consultants (Upgradient) is under contract to William Peters to perform site assessment and quarterly monitoring of groundwater contamination at the Kwikee Foods Mart on Country Club Boulevard in Stockton, California. The site is included in the Local Oversight Program of San Joaquin County Department of Health Services, Environmental Health Division (PHS/EHD), under the supervision of Michael Infurna, REHS. Groundwater moiiitoring is performed quarterly at the site, and the purpose of this report is to present the results of-monitoring during the second quarter of 1998. 2.0 BACKGROUND INFORMATION 2.1 Site Location and Description The project site is located at 2081 Country Club Boulevard in west-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 i3 presently undergoing monitoring of soil and groundwater contamination resulting from activities al that site. 2.2 Previous Work A groundwater monitoring well was installed near the dispenser island in 1990. This well was originally labeled 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/1 (ppb), and benzene was detected at a concentration of 2,107 ppb Toluene, ethylbenzene,and xylene were also detected at elevated levels. Subsequently, monitoring wells KF-1 and KF-2 were installed by Soils Exploration Seivice under the supervision of Upgradient in December 1994. Neither well encountered significant soil contamination, but gasoline and aromatic hydrocarbons were detected above reporting limits in groundwater samples from both wells. Groundwater monitoring since 1994 has confirmed that all three on-site wells are contaminated with gasoline-range hydrocarbons, and concentraions have tended to increase over time in the well that is farthest from the underground storage tanks (KF-2). In March, 1998, both 10,000-gallon unleaded storage tanks were removed, along with the related plumbing. Holes were found in both tanks, and soil and groundwater in the excavation were contaminated. The results led to further assessment in May, the results of which were reported in June. 2