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11/08/2000 14:06 2094671118 AGE STOCKTON PAGE 03 *AW ..i 19 October 2000 AGE-NC Project No. 97-0290 Page 2 of 3 SCOPE OF WORK The scope of work includes advancement of six deep soil borings,two at each of three locations,and installation of up to seven additional ground water monitoring wells to define the vertical and.lateral extent of impacted soil and ground water and to provide the geologic information necessary to properly assess and monitor ground water. AGE proposes to initially advance six deep borings to a depth of 100 feet, two borings at each of three proposed locations,based on the following information: 1)grab water samples at 70 feet at the K& S site were contaminated; 2)information on file at PHS-EHD revealed that a deep soil boring from the USA gas station on 749 West Charter Way encountered hydrocarbon-contaminated soil at a depth of 80 feet;and 3)the vertical extent of contaminated soil and ground water has not been fully defined on the site. The first borings will be cone penetrometer (CPT)holes; the CPT will acquire a continuous lithologic record to define the hydrologic units; the second bore will be advanced to acquire soil and grab ground water samples in targeted zones based on interpreted lithologic data and assessment needs. Because of time consideration in collecting CPT data, and because soil samples will also be collected during installation of the monitoring wells,soil samples will only be collected in targeted zones at CPT locations. One boring location will be near MW1 (Fig. 2), which encountered the highest hydrocarbon concentrations in subsurface soil (Fig. 3). The second location will be near the north end of the property, and the third location will be offsite south of the property, either in the south parking lane or the adjacent sidewalk of West Charter Street. The precise boring locations will be based upon access agreements with the City of Stockton,the owners of adjacent properties and the locations of underground utilities. Soil samples will be collected from selected lithologic units as defined by the CPT data and previously-collected soil-sample data at the site. The strategy for soil sampling is to collect samples from the tops of fine-grain units underlying significant coarse-grain units in the UST area. Soil samples will be preserved as described in the 09 July 1998 Monitoring We11.Installation Tf'orkPlan. Grab ground water samples will be collected from selected hydrologic units as defined by the CPT data; the samples will be placed in 40-ml VOA vials for analysis. In addition to total petroleum hydrocarbons(gasoline), volatile aromatics, and oxygenates, samples also will be analyzed for 1,2 DCA, EDB, ethanol and methanol. During the second phase of the site characterization,up to seven ground water monitoring wells will be installed. Two wells will be installed on the subject property and five will be offsite, as shown on Figure 2. Due to the high concentrations of contaminants encountered in the current existing wells,the distribution of new wells shown on Figure 2 is believed necessary to adequately assess and monitor ground water. Procedures for the advancement ofborings and the installation and sampling of the monitoring wells were described in the Monitoring Well Installation Work Plan, dated 09 July 1998 and prepared by AGE. However, if grab water samples indicate the presence of hydrocarbons in the deeper ground Advanced CeoEnviran mental.Inc.