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r � � <br /> 16WORK PLAN <br /> GROUNDWATER MONITORING WELLS <br /> INSTALLATION AND DEVELOPMENT <br /> VAN DEN BERGH FOODS, INC. <br /> STOCKTON, CALIFORNIA <br /> 1.4 BACKGROUND <br /> BSK & Associates,Inc (BSK) understands that a 1000-gallon gasoline tank, a 550-gallon solvent <br /> tank, and a 520-gallon diesel tank were removed from a common excavation on June 26, 1986 <br /> Analytical results of soil boring R-1 (Stauffer, April 1987) drilled to a depth of 30 feet indicated <br /> diesel concentrations ranging from 14,000 ppm to 61,000 ppm and aromatic volatile <br /> concentrations ranging from 1 ppm Benzene to 22 ppm Xylenes at depths from 15 feet to 30 feet <br /> Chlorinated hydrocarbons were not detected in R-1 No contamination was detected in soil <br /> borings R-2 or R-3, located approximately 10 feet northeast and northwest from the excavated <br /> area. <br />' Results of a groundwater investigation conducted by Weston in October 1988 indicated no diesel <br /> fuel components detectable in soil or water samples collected during installation and sampling <br /> of three monitoring wells installed approximately 50 feet laterally from the former tanks <br /> emplacement The monitoring wells were installed to a depth of approximately 65 feet. Van <br /> Den Bergh Foods reports that these three monitoring wells are presently dry. <br /> In October of 1992 BSK drilled and sampled two soil borings; one boring in the former tank <br /> excavation, and one boring approximately ten feet north of the excavation (the latter was <br /> completed as a groundwater monitoring welI). The results of the soil samples analyzed indicate <br /> that petroleum hydrocarbons were detected to a depth of 70 feet in the soil boring completed in <br /> the former tank excavation and to a depth of 60 feet in the soil boring completed ten feet north <br /> of the excavation Diesel concentrations in the soil samples from the soil boring completed in <br /> the former tank excavation ranged from none detected at a depth of 75 feet, to a maximum of <br /> 23,000 mg/Kg at depths of 10 feet and 15 feet. The concentrations of diesel in the soil samples <br />' from the soil boring located 10 feet north of the excavation ranged from none detected at a depth <br /> of 70 feet to a maximum of 130,000 mg/Kg at a depth of 15 feet. Petroleum hydrocarbons were <br /> not detected in the groundwater samples collected from the groundwater monitoring well installed <br /> by BSK. <br /> 2.0 INTRODUCTION <br /> BSK & Associates, Inc. (BSK) has prepared this Work Plan for installation and development of <br /> two additional groundwater monitoring wells During site activities, BSK will be the prime <br /> drilling contractor (C-57 #490942) <br /> The jobsite is located at 1400 Waterloo Road in Stockton, California (refer to Figure 1, Site <br /> Map) <br /> 1 FP" <br /> &Associates <br />