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CVATew A S S O C I A T E S I N C . Drilling of Soil Borings, Drilling and Installation of Groundwater Monitoring Wells Collection and Analyses of Soil and Groundwater Samples, dated November 17, 1995 for more information. In a letter dated April 11, 2002, the EHD indicated that upgradient monitoring wells MW2 and MW3 could be reduced to annual monitoring and that the lateral and vertical extent of soil contamination remains undefined. The EHD requested submittal of a workplan to define the lateral and vertical extent of soil contamination. In response to the EHD request, H2OGEOL submitted the Work Plan for Additional Soil Characterization dated June 10, 2003, which proposed advancing 14 hand auger borings at the site for the purpose of collecting soil samples. In a letter dated November 14, 2003, the EHD indicated that the proposed scope in the H2OGEOL workplan was not adequate or necessary. The EHD requested that a workplan be prepared in the context of a site conceptual model that includes analytical data collected during removal of a waste oil tank from the site in September 2003. SCOPE OF WORK Planning and Permits ATC will schedule field personnelandequipment, notify Underground Services Alert to locate underground utilities as required, and perform other necessary field preparation and job start-up activities. ATC will obtain drilling permits from EHD and an encroachment permit from the City of Tracy for off site Geoprobe®borings upon approval of this workplan. Advancement of CPT Borings Three deep soil borings will be advanced employing direct push CPT methods at the locations shown on Figure 2. One CPT boring will be advanced in the southern portion of the site to a depth of approximately 75 feet bgs to obtain a continuous description of the subsurface lithology. The data obtained from the southern CPT location will be used to select sampling depths at the remaining two proposed CPT locations.-Depth discrete soil and groundwater samples will be collected from the CPT location adjacent to the USTs and north of the existing building. In addition, a soil sample will be collected at 6 feet bgs from each CPT boring. After the samples have been collected, the CPT borings will be grouted to the surface. Advancement of Geoprobe® Soil Borings Six soil borings will be advanced to first encountered groundwater, estimated at approximately 6 feet bgs. Proposed boring locations are shown on Figure 2. The six borings will be advanced using truck mounted Geoprobe® narrow diameter, direct push technology. Drilling will be conducted by a State-licensed (C57) drilling company. A field geologist will be present to log soil samples. Descriptions of soil types encountered and sample collection intervals will be recorded on boring logs. Soil samples will be collected continuously, sAenviromental\2 5 847\3 7\reports\wkp.doe 3 I