ARCHIVED REPORTS XR0005969 - Laserfiche WebLink

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• 1.0 INTRODUCTION Upgradient Environmental Consultants (Upgradient) is under contract to William Peters to perform 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 Infuma, REHS. The purpose of this report is to present the results of groundwater monitoring during the fourth quarter of 1997. 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 is presently undergoing monitoring of soil and groundwater contamination resulting from,activities at that site. 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/1 (ppb), and benzene was detected at a concentration of 2,107 ppb. Toulene, ethylbenzene, and xylene were also detected at elevated levels. Subsequently, PHS/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 detected 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. Subsequently, groundwater was monitored and sampled in the first and third quarters of 1995, and contaminant concentrations were higher in all wells than they had been in December 1996. For financial reasons, monitoring was discontinued until August of 1997, when Blaine Tech (the consultant for the Chevron site across the street) was permitted to monitor the wells on the Kwikee Foods property as part of their investigation. In general, concentrations had risen in some wells and declined in others since the last time they were sampled in 1995. 2