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Union Ice Company - Yjlerer Street Facility '-AW Phase III Continuing Re-Excavation Activities & Phase IV Remediation Page: 2 first aquifer. MW-413 tested the second aquifer and lower soils zone, and is a double cased well. In May of 1990, a 31 point soil vapor survey was conducted at the site. Soil gasses -• were analyzed for methane content and for gasoline equivalent. The soil vapor survey showed that hydrocarbon vapors in the soil were present in an elongated concentration configuration. This configuration was elongated in the direction of the groundwater flow direction. Results of the soil vapor survey were reported to San Joaquin County Department of Health in our report of June, 1990. In February of 1991, a remedial excavation of about 2,000 cubic yards of petroleum contaminated soils was undertaken at this site. in addition to this excavation, an _ extraction well (MW-8) and a down gradient monitoring well (MW-9) were installed into the first aquifer. In March of 1991, a 12 hour aquifer pumping test was performed on well MW-8. This well was pumped at a constant discharge rate of 4.16 gpm for 12 hours. Drawdown was monitored for this well as well as all other wells on the property during the test. The recovery of these wells was then monitored for 12 hours. The latest phase of work was designed primarily to explore the extent of contamination plume which extended to the southeast of the previous excavations. This area of the plume was not removed because of the presence of a sewer line, which runs north to south in the area. In addition, the latest phase of work was intended to test the effectiveness of the excavations in removing the contamination in other areas of the plume. The work was carried out between March 25 and 28, 1992. A total of 8 soil borings were drilled to a depth just above the groundwater level by Osterberg & Stewart, _ licensed drilling contractors, of Modesto, California. The borings were drilled using a 7.25 inch diameter hollow stem flight auger and the soil was cored continuously, using a wireline coring device. Samples were collected in 2 112 foot intervals. A detailed stratigraphic log, listing sediment type and description, was kept for each boring. 3.0 PROPOSED RE-EXCAVATION _ The purpose of the proposed re-excavation is to remove the remaining contaminated soil in order to reduce the potential impact to the groundwater table. The excavation will consist of the removal of approximately 2,000 cubic yards of soil (Figure 3). The