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10 METHODS AND PROCEDURES <br /> 1 1 Soil Samplinz and Contamination Reduction <br /> Soil borings and soil sampling were performed under the direction of a Delta geologist The soil borings <br /> were advanced using a truck-mounted hollow-stem auger drill ng To reduce the chances of <br /> cross-contamination, all downhole drilling equipment was steam-cleaned prior to drilling To reduce <br /> cross-contamination between samples, the split-barrel sampler was washed in a soap solution and <br /> double-rinsed between each sampling event <br /> Soil sampling was conducted in accordance with ASTM 1586-84 Using this procedure, a 2-inch <br /> outside-diameter split-barrel sampler or a 2-mch inside-diameter California-type sampler luted with three <br /> 6-inch long brass sample tubes is driven into the soil by a 140-pound weight falling 30 inches After an <br /> initial set of 6 inches, the number of blows required to drive the sampler an additional 12 inches is known <br /> as penetration resistance or the "N" value The N value is used as an empirical measure of the relative <br /> density of cohesionless soils and the consistency of cohesive soils <br /> Upon recovery, a portion of the soil sample was sealed in a ziplock bag for later screening with a <br /> photoiomzation detector (PID) Another portion of the soil sample was used for classification and <br /> description The soil sample collected in the leading brass tube within the California-type sampler was <br /> labeled, sealed, and stored at approximately 4° C pending sample selection and transport to the laboratory <br /> for chemical analysis <br /> 12 Soil Classification <br /> As the samples were obtained m the field, they were classified by the geologist in accordance with the <br /> Unified Soil Classification System (USCS) Representative portions of the samples were retained for <br /> further examination and for verification of the field classification Logs of the borings indicating the depth <br /> and identification of the various strata, the N value, and pertinent information regarding the method of <br /> maintaining and advancing the borehole were made <br /> 1 3 Soil Sample Screenin 1hNu Portable Photmonization Detector Method <br /> After the soil samples contained in ziploc bags were brought to ambient temperature, the headspace <br /> vapors within the bag were screened with a organic vapor meter equipped with a 10 2 eV lamp The corner <br /> LRP007 809 <br />