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I LMLEI=DSNILL-NEIiKENNOFF, INC September 1990 SITE INVESTIGATION SOIL SAMPLING Three six-inch soil borings were installed by LH on August 6 and 7, 1990 One of the borings, SB21, drilled to a depth of 34 feet, was reamed with a ten-inch hollow-stem I auger and converted into a 73-foot deep replacement monitoring well (MW6) The two remaining borings, SB22 and SB23, were each drilled to a depth of 60 feet Discrete sod samples were collected at 5 feet, and at 5-foot intervals to the bottom of each boring Precise boring locations are shown on Figure 1. Drilling was conducted dry with no fluids added to the borehole or lubrication to the drilling equipment A sampler attached to the drilling rods inserted down the center of the hollow-stem auger was used to collect the samples The sampler was a California modified (2.5-inch outside diameter) split-spoon sampler equipped with clean brass tubes I The sampler was driven 18 inches into the undisturbed ground beyond the tip of the auger by a 140-pound hammer having a 30-inch drop. The sample was then withdrawn from the auger and the tubes removed. This sampling technique was used for all borings I except S1321, which was drilled using a continuous sampling method. The sampler was attached to the hollow-stem auger and advanced as part of the auger unit creating an approximately 30-inch long core sample Samples were removed from the sampler and classified using the Unified Soil Classification System. A sample was collected every five feet and placed in a clean glass container for laboratory analysis The split-spoon sampler was brushed and washed with a trisodium phosphate (TSP) and water solution between each sampling interval All sample tube inserts and drilling equipment were thoroughly cleaned with high pressure, hot water prior to use to prevent potential cross-contamination between borings The test borings were completely backfilled with a cement grout mixture immediately after the samples were obtained Once removed, all samples were wrapped, carefully marked, and identified The samples were then carefully preserved for analysis in accordance with EPA and California Department of Health Services (DOHS) protocol. Before transport to the laboratory, samples were cooled to 4 degrees Celsius at the site and maintained at that temperature until they were received at the laboratory. Prior to transport, the samples were logged onto a chain-of-custody form identifying the project number, sample type, container type, sample identification, sampler and date. The samples were picked up by Superior Analytical, Inc., where a laboratory representative signed the chain-of-custody form The ' samples were then placed in a refrigerator until they were extracted and analyzed prior to their expiration date 2