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v URS Greiner Woodward Clyde Ms. Carol Oz Page 2 San Joaquin County- Public Health Services Environmental Health Division March 13, 2000 Drilling and Sample Collection To assess the lateral and vertical extent of soil contamination and the presence or absence of groundwater contamination, URSGWC proposes installing four soil borings at the Site. The borings are proposed to be Iocated adjacent to the current UST. The borings will be placed to confirm the soil contamination previously identified. A figure showing the proposed boring locations is included as Attachment I. Underground Service Alert(USA)will be notified a minimum of 48-hours prior to commencement of field activities. The borings will be drilled with 8.25-inch outside diameter(OD)hollow stem augers to a total depth of approximately 60 feet bgs. Soil samples will be collected using a California-modified split spoon sampler at 5-foot intervals beginning at 5 feet bgs and continue until groundwater is encountered; anticipated to be at approximately 55 feet bgs. A portion of each soil sample will be retained for field screening analysis. Based on field screening observations, two soil samples from each boring will be submitted to Curtis & Tompkins, Limited (Curtis & Tompkins), a California State Certified Laboratory, for analysis of TPH-G by EPA method 8015 modified and BTEX,MTBE, tert butyl alchohol (TBA), di-isopropyl ether (DIPE), ethyl tert-butyl ether (ETB), and tert-amyl methyl ether (TAME) by EPA method 8260. Each soil sample will be delivered to the laboratory within the appropriate holding times and will be accompanied by the chain of custody (COC) documents. Groundwater grab samples will be collected from each boring. The samples will be collected by lowering a disposable dedicated bailer slowly through the open augers to the water and allowing it to fill while causing a minimum of agitation to the water column. Groundwater samples will be carefully transferred to precleaned, laboratory-provided sample containers. Once collected,the sample bottles will be labeled with the time and date of collection,project and sample identification codes, the sampler's initials,the type of analysis to be performed, and the preservative used, if any. The samples will be then sealed in plastic bags and stored in an ice-filled chest at approximately 4C until delivery to Curtis & Tompkins. Each groundwater sample will be delivered to the laboratory within the appropriate holding times and will be accompanied by the COC documents. The groundwater samples will be submitted for analysis of TPH-G by EPA Method 8015 modified, and BTEX, MTBE, TBA, DIPE,ETB, and TAME by EPA Method 8260. Soil cuttings generated during the drilling activities will be placed in labeled 55-gallon Department of Transportation(DOT)-approved steel drums pending disposal. The equipment used in the drilling and sampling of the borings will be thoroughly cleaned using a high temperature,high pressure steam cleaner before commencing work and between each boring. The waste water generated during the equipment cleaning will be stored in labeled 55-gallon DOT-approved steel drums pending disposal. Each of the soil borings will be abandoned by tremicing a cement grout mixture from the base of the boring to the surface. The grout will be monitored for settling and more will be added as necessary. 1:1142]4103_Stockton\Workplan.doc