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Evaluation of Hydrocarbons May 17, 1990 <br /> Waterfront Redevelopment, Stockton, California AGS 39048-2W <br /> geologist, and the earth materials in the borings will be logged as drilled. The borings will <br /> be used to construct ground-water monitoring wells and will be drilled to approximately 10 <br /> feet below the uppermost zone of saturation. <br /> During drilling, soil samples will be collected from 5 feet below existing grade to the total <br /> depth of the boring at 5-foot intervals or obvious changes in soil type. Soil samples will be <br /> collected using a California-modified, split-spoon sampler equipped with clean brass sleeves. <br /> Samples will be collected by advancing the auger to a point immediately above the sampling <br /> depth and driving the sampler through the auger into the native soil. The sampler will be <br /> driven 18 inches or to refusal with a standard 140-pound hammer repeatedly dropped 30 <br /> inches. The number of blows required to drive the sampler each successive <br /> 6-inch interval will be counted and recorded to give an indication of soil consistency. <br /> Sampling refusal will be defined as more than 50 blows for a 6-inch interval. <br /> A representative sample from each sample interval will be tested with a photoionizing <br /> organic vapor meter (OVM). The OVM is useful for evaluation of relative concentrations <br /> of volatile hydrocarbons but cannot be used to measure levels of hydrocarbons with the <br /> confidence of laboratory analysis. Soil samples selected for chemical analysis will include <br /> the sample taken from immediately above the ground-water surface and the sample with <br /> the highest OVM reading in each boring. <br /> 10 <br /> N <br /> Applied GeoSystems <br />