ARCHIVED REPORTS_XR0009337 - Laserfiche WebLink

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obtained from the PHS/EBD In addition, Underground Services Alert (USA Alen) will be ' contacted to identify underground public utilities, which will be marked in the field prior to commencement of field activities The site owner will also identify any underground utilities and ' piping of which they may have knowledge Three shallow groundwater monitoring wells will be installed and soils and groundwater sampled ' to characterize the lateral extent of PHCs in soils and groundwater and to monitor the local groundwater gradient The proposed locations of the monitoring wells, designated MW 3-1 through MW 3-3, are shown on Figure 2 Based on a discussion with PHS/EHD, the soil sampling ' results of the initial subsurface investigation indicate that only one soil sample (from a depth of 25 feet) needs to be obtained in each boring ' The monitoring wells will be installed, developed, and sampled in general accordance with ASTM Standard D 5092-90, "Design and Installation of Groundwater Monitoring Wells in Aquifers," and ' ASTM Standard D 4448-85a, "Sampling Ground Water Monitoring Wells" ' 3.1.1 Pilot Borings and Soil Sampling Based on present information, it is anticipated that groundwater will be encountered at a depth of about 10 feet bgs Unless subsurface conditions encountered during drilling dictate otherwise, the proposed screen interval for the wells will be from 5 to 25 feet bgs tAn 8-inch diameter(4-ranch I D auger) pilot boring for each of the monitoring wells will be drilled to a depth of about 25 feet bgs Soil samples will be obtained by coring Conng wnll be accomplished by driving a nominal 2-foot long split-spoon sampler equipped with brass liners The cores will be quickly inspected for color, appearance, and composition, and then capped Capping of the brass liners will be done by placing polytetrafluoroethylene (PTFE) sheeting over the ends ' and covering the sheeting with polyethylene caps Capped samples will be sealed with rubber or PVC tape and will be labeled, enclosed m plastic bags, and stored in ice-cooled chests until delivered under chain-of-custody procedures to a California DHS-certified laboratory for PHC analysis Soil ' samples will be analyzed for concentrations of BTEX using EPA Method 8020, and 'YPHg using the gas chromatography/flame ionization detector(GC/FID) method Since no soil samples from ' the initial subsurface investigation contained any oxygenated compounds, soil samples during this investigation will not be analyzed for these compounds ' Soil cuttings from the borings will be lithologica.11y logged by the field geologist using the Unified Soil Classification System Soil cuttings generated during drilling will be temporarily stored on-site during drilling and well installation, and transported to a designated on-site area after completion ' of the wells a3,4dmv wpn 5 PHILIP P. Ross, R.G. 1