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z w Mr.M.Scott Mansholt—CEMC March 29,2006 Site Investigation Work Plan Page 3 of 5 Banta Road—UPRR February 2004 a SAIC began work at the SSJID excavation during the construction of the bore- and jack pit in preparation for the 30 inch-diameter water main installation beneath the UPRR ROW. The bore-and-jack pit was constructed approximately 75 feet north of the UPRR track. The horizontal boring for the SSJID water main extended approximately 200 feet south as shown on Figure 2. SAIC staff was present to direct the segregation of affected soil,document the conditions of the soil, and photograph the excavation activities. SAIC field staff recorded the presence and degree of petroleum-affected soil observed in the trench and noted other soil characteristics of importance. Because the shored pit provided limited visibility of the pit walls, soil cuttings were observed from outside the trench and observations were recorded in a field logbook. A soil sample submitted for fuel fingerprint analyses was collected from the soil stockpile generated during the SSJID construction activities. The analysis concluded that the hydrocarbons are most likely weathered crude oil or possibly weathered Bunker C fuel, and that the sample contains prominent biomarkers in the C27 to Cao range typical of many San Joaquin Valley(SJV) crude oils and bunker fuels refined from SJV crude oils. Based on trench observations recorded during the initial excavation activities of the bore-and-jack pit,petroleum-affected soil extended from approximately 14 to 16.5 feet bgs. The vertical extent of affected soil could not be determined. Along the southern sidewall of the bore-and-jack pit, visible petroleum-affected soil was first encountered at the face of the sidewall of the borehole and extended approximately 10 feet into the borehole. Non-affected soil identified as clay was observed from approximately 10 to 120 feet into the borehole. From 120 to 175 feet,affected soil (clay)was again observed in the borehole. Non-affected soil was observed from 175 to 200 feet into the borehole,which terminated at the receiving pit as shown on Figure 2. During excavation activities,groundwater was not encountered in the bore-and-jack pit. A report of these activities was prepared in May 2004. A copy of this report is included as Attachment A. OBJECTIVE AND SCOPE Based on the results of prior site investigations and ongoing groundwater monitoring and sampling near the site, SAIC proposes to advance five soil borings at the locations shown on Figure 2. Information from these soil borings will be used to laterally define petroleum hydrocarbons in the soil and groundwater off site. PERMITTING AND ACCESS SAIC will submit the appropriate boring permits to San Joaquin County Environmental Health Department(SJCEHD)for approval. The proposed wells are on county property;CEMC will secure access to those properties prior to any fieldwork. A site-specific health and safety plan(HASP)will be prepared and approved prior to any field activities. The HASP will include potential hazards and general hazard controls;driving directions to the nearest hospital and a hospital route map; critical contact and emergency information;and job safety analyses of the work activities to be performed. The HASP will be kept on site and reviewed daily with all on-site personnel. In addition to the HASP,a Journey Management Plan(IMP)will be drafted and approved prior to the investigation in order to identify optimal ingress and egress locations and mitigate any potential traffic issues,and will be provided in advance to all subcontractors anticipated at the site for their approval. 4. SAIC,2004. Summary of field Activities,South San Joaquin Irrigation District Pipeline,Banta Road,Tracy, California. May.