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I 5-MI FIVE l.o Nnmio13S 1.1 Soil Sam lin Soil borings and soil sampling will ba performed under the direction of a Delta engineer or geologist. The soil borings will be advanced using a truck-mounted hollow-stem auger drill rig. To reduce the chances of cross-contamination between boreholes,ail downhole drilling equipment will be steamed-cleaned between each .1 boring. To reduce cross-contamination betweca samples, the split-barrel sampler will be washed in a soap solution and double-rinsed between each sampling event- Soil sampling will be done in accordance with ASTM 1586-84. Using this procedure, a 2-inch outside-diameter split-barrel sampler or a 2-inch inside-diameter California-type sampler is driven into the soil by a 140-pound weight falling 30 inches. After an initial set sof 6 inches, the number of blows . required to drive the sampler an additional 12 inches is known as penetration resistance,or the"N' value. The N value is used as an empirical measure of the relative density of cohesionlcss soils and the consistency of cohesive soils. 'ne sampler will be lined with three 2-inch diameter,6-inch long brass tubes. Upon recovery,a portion of the soil sample will be placed int,a soil sample collection jar and sealed for later screening with a photoionisation detector(PID), Another portion of the soil sample will be used for classification and description. The soil sample coliec,.d in the lower most brass tube within the California-type sampler will be capped,packaged,and preserved according to accepted EPA procedures for possible laboratory analysis. 1.2 Soil Classification As the samples are obtained in the field,they will be classified by the crew chief/geologist in accordance with the United Soil Classification System (USC5). Representative portions of the samples will be retained for further examination and for verification of the field classification. Logs of the borings indicating the dopth and identification of the various strata, the N value,and pertinent information :? regarding the method of maintaining and advancing the borehole will be made. 1.3 Soil Sample Screenin hodAl The portion rf thq soil sample retained for organic vapor screening will be placed into a clean sta:;tdnrd sail sample collo ,,'n jar. Each jar will be filled approximately one-half full,then the mouth of the jar - — will be-cc,vered with aluminum foil and capped with a lid. .iars will bo placed out of direct sunlight for at least 20 minutes,allowing time for the.air in Neadspace and soil to equilibrate. The probe of the PID will be inserted through the aluminum foil,and the highest observed reading recorded on th?soiI boring log.