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Conestoga-Rovers & Associates <br /> STANDARD FIELD PROCEDURES FOR SOIL BORING AND MONITORING WELL <br /> INSTALLATION <br /> This document presents standard field methods for drilling and sampling soil borings and installing, <br /> developing and sampling groundwater 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 /> �iI samples are collected to characterize subsurface lithology, assess whether the soils exhibit obvious <br /> di ocarbon 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 <br /> working under the supervision of a California Professional Geologist (PG). <br /> Soil Boring and Sampling <br /> Soil borings are typically drilled using hollow-stem augers or direct-push technologies such as the <br /> Geoprobe®. Soil samples are collected at least every five ft to characterize the subsurface sediments and <br /> for possible chemical analysis. Additional soil samples are collected near the water table and at <br /> lithologic changes. Samples are collected using lined split-barrel or equivalent samplers driven into <br /> undisturbed sediments at the bottom of the borehole. <br /> Drilling and sampling equipment is steam-cleaned prior to drilling and between borings to prevent <br /> cross-contamination. Sampling equipment is washed between samples with trisodium phosphate or an <br /> equivalent EPA-approved detergent. <br /> Sample- Analysis <br /> Sampling tubes chosen for analysis are trimmed of excess soil and capped with Teflon tape and plastic <br /> end caps. Soil samples are labeled and stored at or below 4° C on either crushed or dry ice, depending <br /> upon local regulations. Samples are transported under chain-of-custody to a State-certified analytic <br /> 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 <br /> is capped with plastic end caps and set aside to allow hydrocarbons to volatilize from the soil. After ten <br /> to fifteen minutes, a portable volatile vapor analyzer measures volatile hydrocarbon vapor concentrations <br /> in the tube headspace, extracting the vapor through a slit in the cap. Volatile vapor analyzer <br /> measurements are used along with the field observations, odors, stratigraphy and groundwater depth to <br /> select soil samples for analysis. <br /> i <br /> Page 1 of 3 <br />