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1.0 METHODS <br />' 1.1 Soil Sampling and Contamination Reductl n <br /> Soil borings and soil sampling will be performed under the direction of a Delta engineer <br />' or geologist The soil borings will be advanced using a truck-mounted drill rig <br /> utilizing hollow-stem augers <br />' To reduce the chances of cross contamination between boreholes, all down-hole drilling <br /> equipment will be cleaned between each boring To reduce cross contamination between <br />' samples, the split--barrel sampler will be washed in a soap solution and double rinsed <br /> between each sampling event <br />' Soil sampling will be donne in accordance with ASTM 1586-84 Using this procedure, a two- <br /> inch OD split-barrel sampler or a two-inch ID California-type sampler is driven into <br />' the soil by a 140-pound weight falling 30 inches After an initial set of six inches, the <br /> number of blows required to drive the sampler an additional 12 inches is known as <br /> penetration resistance, or the "N" value The N value is used as an empirical measure <br />' of the relative density of cohesionless soils and the consistency of cohesive soils <br /> Upon recovery, a portion of the soil sample will be placed into a glass jar and sealed <br /> for later screening with a photoionization detector Another portion of the soil sample <br /> will be used for classification and description That part of the soil sample collected <br />' in brass tubes within the California-type sampler will be stored at approximately 4°C <br /> for transport to the laboratory <br /> 1.2 Soil CIIIssification <br /> As the samples are obtained in the field, they will be classified by the crew <br /> chief/geologist in accordance with ASTM D 2488-84 Representative portions of the <br /> samples will then be returned to the laboratory for further examination and for <br />' verification of the field classification Logs of the borings indicating the depth and <br /> identification of the various strata, the N value, water-level information and <br />' pertinent information regarding the method of maintaining and advancing the bore hole <br /> will be made Charts illustrating soil classification procedure and the descriptive <br /> terminology and symbols used on the boring logs will also be made <br /> 1.3 Soil-Samigig ScreeninalhNii-Photoionizatlon Detector-Method <br /> After soil-sample ,tars have been brought to room temperature, the head-space vapors of <br /> the soil-sample jars will be screened with an hNu phototonization detector equipped with <br /> 1 <br />