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LM LEEDSHILL HERKENHOFF, INC SITE INVESTIGATION 3.1 Soil Sampling 1 Seven six-inch soil borings were installed by LH on November 16 - 21 1989. Two of the borings, drilled to depths of 60 and 65 feet, were reamed with a ten-inch hollow-stem auger and converted into 63-foot deep monitoring wells (MW4 and MW5) (see Section 3.2 Monitoring Wells) . Three of the borings were drilled to a depth of 40 feet below the ground surface (TBS, TB6, and TB7) . The two remaining borings, TB8 and TB9, were drilled to a depth of 30 feet. Discrete soil samples were collected at 2'/2 feet, 5 feet, and at 5-foot intervals to the bottom of each boring. Precise boring locations are shown on Figure 2 Drilling was conducted dry with no fluids added to the borehole or lubrication to the drilling equipment A sampler attached to the dri111ng rods inserted down the center of the hollow-stem augers 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. 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 The sample was then withdrawn from the auger and the tubes removed.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 except T86, 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 far for laboratory analysis. The split-spoon sampler was brushed and washed with distilled water between each sampling interval . All sample tube inserts and drilling equipment were thoroughly cleaned Frith high pressure, hot water prior to use to prevent potential cross-contamination between borings. The test borings were completely backfilled with a sand-cement grout mixture immediately after the samples were obtained. Groundwater was not encountered in any of the borings, with the exception of MW4 and MWS. 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 vere 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. A photoionization detector was used to field monitor the volatile petroleum hydrocarbon vapors emitted from each soil sample. The field instrumentation did not replace the analytical laboratory testing. ..go