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' Mr. Al Blevens Project 20939-011.001 April 24, 1998 Page 2 sampler fitted with an acrylic liner for containment of the soil sample. In addition, an attempt was made to collect grab groundwater from first encot ntered groundwater and from the bottom of each boring by pushing a temporary 1-inch-c iameter machine-slotted poly-vinyl casing approximately 2 feet beyond the end of the ampler and collecting a water sample by use of a one-half inch-diameter stainless-st 1 bailer. Sampling and drilling equipment were cleaned using an alconox wash between water samples and between geoprobe borings. When advancing the geoprobe in boring GP-5 from 4 feet to 8 feet, the driller noted the ' sampler appeared to be pushing a rock. No soil sample was recovered from the 4 to 8 foot sample run. When attempting to collect a grab groundwater sample from first encountered groundwater in boring GP-5, water would not ow into the temporary ' casing (casing was set from 6 to 8 feet bgs). The driller pushed the casing an additional two feet (to a total depth of 10 feet bgs) in an attempt to induce groundwater to flow into the casing. However, due to the increased content of fines within the soil, water still would not flow into the casing. Consequently, at the request of San Joaquin County DPW, the casing was advanced to 14 feet bgs where soil and gr undwater samples were ' collected. Soil samples were described on a boring log by the EMCON geologist supervising ' site activities utilizing the Unified Soil Classification System and ASTM Method D-2488-90, (see Exploratory Boring Logs in Appendix A for boring information). Soil samples from each sample interval were field screened for petroleum ' hydrocarbon impacts using a flame ionization detector (FID). Field screening results were recorded on the boring logs. ' Samples from each sample interval were preserved for laborato analysis by cutting the sample liner into approximately 6-inch-long sections, sealing a sections with Teflon® tape and plastic end caps, labeling the sections, placing them oil ice, and delivering the samples to Sparger Analytical Laboratory (State Certification No. 1264) in Sacramento, California, along with the appropriate chain-of-custody documentation. Soil samples selected for chemical analysis were the samples from nearest the capillary fringe or those with elevated FID readings, and the samples collected from the bottom of the soil boring. Groundwater samples selected for chemical analysis were sam les from the boreholes • nearest and farthest from the potential source area, GP-I and GP-5, with one groundwater sample collected from near the surface of first encountered groundwater, and one sample collected from near the bottom of the boring. SACVC:\THORNTON.DOC-96\cmetzinge:I Emcon