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16.W %4001 <br /> CAMBRIA <br /> STANDARD FIELD PROCEDURES FOR MONITORING WELLS <br /> This document presents standard field methods for drilling and sampling soil borings and installing, <br /> developing and sampling ground water monitoring wells. These procedures are designed to comply with <br /> Federal, State and local regulatory guidelines. Specific field procedures are summarized below. <br /> SOIL BORINGS <br /> Objectives <br /> Soil samples are collected to characterize subsurface lithology, assess whether the soils exhibit obvious <br /> hydrocarbon or other compound vapor or staining, and to collect samples for analysis at a State-certified <br /> laboratory. All borings are logged using the Unified Soil Classification System by a trained geologist working <br /> under the supervision of a California Registered Geologist(RG)or a Certified Engineering Geologist(CEG). <br /> Soil Boring and Sampling <br /> Soil borings are typically drilled using hollow-stem augers or push technologies such as the Geoprobe. Soil <br /> samples are collected at least every five ft to characterize the subsurface sediments and for possible chemical <br /> analysis. Additional soil samples are collected near the water table and at lithologic changes. Samples are <br /> collected using lined split-barrel or equivalent samplers driven into undisturbed sediments at the bottom of the <br /> borehole. <br /> Drilling and sampling equipment is steam-cleaned prior to drilling and between borings to prevent cross- <br /> contamination. Sampling equipment is washed between samples with trisodium phosphate or an equivalent <br /> EPA-approved detergent. <br /> Sample Analysis <br /> Sampling tubes chosen for analysis are trimmed of excess soil and capped with Teflon tape and plastic end <br /> caps. Soil samples are labeled and stored at or below 41C on either crushed or dry ice, depending upon local <br /> regulations. Samples are transported under chain-of-custody to a State-certified analytic laboratory. <br /> Field Screening <br /> One of the remaining tubes is partially emptied leaving about one-third of the soil in the tube. The tube is <br /> capped with plastic end caps and set aside to allow hydrocarbons to volatilize from the soil. After ten to fifteen <br /> minutes, a portable photoionization detector(PID)measures volatile hydrocarbon vapor concentrations in the <br /> tube headspace,extracting the vapor through a slit in the cap. PID measurements are used along with the field <br /> observations, odors, stratigraphy and ground water depth to select soil samples for analysis. <br /> Water Sampling <br /> Water samples, if they are collected from the boring, are either collected using a driven Hydropunch type <br /> sampler or are collected from the open borehole using bailers. The ground water samples are decanted into <br /> the appropriate containers supplied by the analytic laboratory. Samples are labeled,placed in protective foam <br /> sleeves, stored on crushed ice at or below 411C, and transported under chain-of-custody to the laboratory. <br /> Page 1 of 3 <br />