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2. Mark boring locations and clear for underground utilities. 3. Notify SJCEHD a minimum of 48 hours before scheduled work is to begin 4.1.2 Soil Boring, Classification, Field Screening, and Sampling The locations of the borings are proposed to help determine if the subject property has been impacted by the historic use as a services station with record of an underground storage tank (UST) and providing vehicle maintenance. The conceptual site model takes into consideration the potential distributions of contaminants with respect to the property's behaviors, fate and transport characteristics of the contaminant in a setting such as that being assessed. The sampling plan was designed to provide for the collection of potentially contaminated environmental media, if they occur, at locations or as close to locations and depths where the highest concentrations are likely to occur. All borings will be advanced by a licensed C-57 contractor. The boreholes will be performed using a mobile Geoprobe 6600 boring rig. The rig will advance nominal two- inch outside diameter Geoprobe casings with cellulose acetate butyrate (CAB) liners. The borings will be logged in accordance with standard geologic procedures by a qualified geologist or engineer. All borings will terminate at first observed groundwater or 30 feet bgs which ever comes first. A total of 18 soil samples is anticipated to be submitted for chemical analysis. A section of the CAB liner, approximately 4 to 6 inches will be cut, ends sealed with Teflon patches and covered with plastic end caps. The soil samples will be labeled, recorded on the chain of custody, and immediately placed into a pre-cooled ice chest at approximately four degrees Centigrade. Once the soil groundwater interface is observed the borings will be advanced an additional 4 feet. The drill rods will be removed from the boring and slotted PVC screen will be inserted in the boring. The casing will be allowed to fill before sample collection. A new Teflon water retrieval hose will be utilized to facilitate groundwater sampling. Water samples will be decanted into one (1) 1-liter amber and four (4) VOAs preserved with hydrochloric acid. A total of 9 groundwater samples is anticipated to be submitted for chemical analysis. Each sample will be labeled and placed into a pre-cooled ice chest at a temperature of approximately 40C during transportation to the laboratory. Proper chain-of-custody protocol will be followed at all times. A copy of the field data sheet, results of sample analyses, and chain-of-custody forms will be included in the appendices of the technical report. 03103126 A&M ENVIR ONMENTAL SERVICES 3 Work Plan for Site Investigation 1049& 1016 S. Wilson Way, Stockton, CA