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fi r BITE CONTA14INAATION WORKPLAN Arts and Artists 204 East Lodi Ave. SITE DESCRIPTION The site is located in a flat cul area in central Lodi North Quadrangle, USGS (Figure 1 - Location Map, 7 .5 Minte Lodi Topographic Map Series, 1976) . It is our understanding that5allon underground fuel removed by Thorpe OilsCorain tank containing leaded gasolinewas January, 1987 . Soil samples collected at that containedtime The indicated to 1404 ppm gasoline, along with toluene and xyline petroleum leak prompted then Joaquin county extent of soil contamination. Health to require assessment of th Three soil borings were subsequently drilled in August, 1987 and converted to groundwater monitoring wells. A water sample was om each well. All were contaminated collected by Weiss Associates fr with benzene, and both MW-1 and MW-3 also contained gasoline. Of the soil samples, only those from MW-1 were contaminated. These results provide some indutado nottion fa11oWthe 1deline�ti01� Ofateral and tgrOLllldWatQ�' ical extent of soil contamination, b contamination. BITE GEOLOGY The site is underlain by unconsolidated Quaternary sediment, mostly sand but including some silt and clay. The following discussion is based on data obtained from the site assessment report of Weiss Associates dated 16 October 1987. Drilling to depths of 70 ft has revealed that the near-surface deposits can be divided into two main sequences. Sand is dominant in the upper 35-40 ft. It is reddish near the surface, grading downward to grayish or yellowish brown, and contains an estimated 5-15% silt. Silt and clay beds are uncommon in this interval. The sequence from about 35 ft to 70 ft consists of interbedded silt, clay, and sand beds that average 3-4 ft in thickness. These beds are grayish brown to reddish brown in color. DEPTH TO GROUNDWATER According to the Weiss report, the depth to groundwater was 50 ft during August and September of 1987. The water level has since dropped, and in November, 1991, two of three monitoring wells were dry (letter from Earth Systems Environmental to Central Valley Regional Water Quality Control Board, 25 November 1991) . Floating product was present at a depth of approximately 60 ft in the third well.