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CAMBRIA <br /> STANDARD FIELD PROCEDURES FOR MONITORING WELL INSTALLATION <br /> This document presents standard field methods for drilling and sampling soil borings and <br /> installing, developing and sampling groundwater monitoring wells. These procedures are <br /> designed to comply with Federal, State and local regulatory guidelines. Specific field procedures <br /> are summarized below. <br /> SOIL BORINGS <br /> Objectives <br /> Soil samples are collected to characterize subsurface lithology, assess whether the soils exhibit <br /> obvious hydrocarbon or other compound vapor or staining,and to collect samples for analysis at a <br /> State-certified laboratory. All borings are logged using the Unified Soil Classification System by <br /> a trained geologist working under the supervision of a California Registered Geologist(RG). <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 <br /> sediments and for possible chemical analysis. Additional soil samples are collected near the <br /> water table and at lithologic changes. Samples are collected using lined split-barrel or equivalent <br /> samplers driven into undisturbed sediments at the bottom of the borehole. <br /> Drilling and sampling equipment is steam-cleaned prior to drilling and between borings to <br /> prevent cross-contamination. Sampling equipment is washed between samples with trisodium <br /> phosphate or an equivalent EPA-approved detergent. <br /> Sample Analysis <br /> Sampling tubes chosen for analysis are trimmed of excess soil and capped with Teflon tape and <br /> plastic end caps. Soil samples are labeled and stored at or below 4° C on either crushed or dry <br /> ice,depending upon local regulations. Samples are transported under chain-of-custody to a State- <br /> 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. <br /> The tube is capped with plastic end caps and set aside to allow hydrocarbons to volatilize from <br /> the soil. After ten to fifteen minutes, a portable volatile vapor analyzer measures volatile <br /> hydrocarbon vapor concentrations in the tube headspace, extracting the vapor through a slit in the <br /> cap. Volatile vapor analyzer measurements are used along with the field observations, odors, <br /> stratigraphy and groundwater depth to select soil samples for analysis. <br /> Page 1 of 3 <br />