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__ _ _ _g __ -s 1.0 hMODS 1.1 Soli Samnlfne and ContarnfnatEon Reduction Soil borings and soil sampling was performed under the direction of a Delta engineer or geologist. The soil borings were advanced using a truck-mounted drill rig utilizing hollow-stem augers. To reduce the chances of cross contamination between boreholes,all down-hole drilling equipment were cleaned between each soil boring. To reduce cross contamination Between samples, the split-barrel sampler was washed in a soap solution and double,rinsed Between each sampling event. Soil sampling was 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 of 6-inches, the number of blows required io drive the sampler an additional 12 inches is known as penetration resistance, or the 'N' value. The N r value is used as an empirical measure of the relative density of cohesionless soils and the consistency of I cohesive soils. y � .tea i Upon recovery,a portion of the soil sample was placed into a glass lar and sealed for later screening with a photoionisation detector (PID). Another portion of the soil sample was used for classification r and description. That part of the soil sample collected in brass tubes within the California-type sampler i ' was stored at approximately 4oC for transport to the laboratory. I.2_Sofl Classlflcatfon Ems+ As the samples are obtained in the field, they were classified by u'e rrew chief/geologist in accordance r with ASTMONN-84. Representative portions of the samples were returned to the laboratory for further ' examination and for verification of the field classification. Logs of the borings indicating the depth and i� r identification of the various strata, the N value, water-level information and pertinent information r r regarding the method of maintaining and advancing the bore hole were made. W 13 Soil-Sample SarmnlngfhNu PhOLMOMplion Detector Method t �» After soil-sample jars have been brought to room temperature, the head-space vapors of the soil-sample t "? jars were screened with an hNu photoionization detector equipped with a 10.2 eV lamp calibrated to benzene for direct-reading-in_parts-per-million-(ppm).-The sample jar lid-will be opened-and-the-hNu - `- T- probe immediately placed within the head space of the jar. The highest observed reading was recorded. o 3 y