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January 3. 1991 BA,iie&CHANCE ASSOCIATES <br /> File No. 2037-1 <br /> • Hydrocarbon (HC) Soil Contamination <br /> Reference is made to the existence of hydrocarbon contaminated soils which may be <br /> present at the site (U.S. Testing, 6/90; Nations Groundwater, 10/90) however, no <br /> data provided to Balbi&Chang Associates confirmed the existence of such impacted <br /> soils. This "lack of information" is also pointed out by Earth Systems <br /> Environmental (11/90) in addition to a conversation with John Cummings of SCS <br /> who stated they had no record of testing or removing any "stained" soils. <br /> The mention of HC impacted soils was made in the Dames & Moore report stating <br /> M the existence of stained soils and specific locations suspected of containing HC's. <br /> A notation in the report states these soils were removed. <br /> M • Soils and Groundwater <br /> IF <br /> M Data on the regional geology and hydrology was provided by U.S. Testing. They <br /> state that regional groundwater flow is towards the north-northwest. Depth to first <br /> groundwater is estimated to be approximately 8-12 feet. This is consistent with the <br /> SCS UST removal which demonstrated groundwater in the tank pit at 8' below <br /> grade. <br /> No data was reviewed concerning any impact to groundwater currently existing at <br /> the site. As stated previously, the groundwater sampled from the former UST pit <br /> demonstrated non-detectable levels of petroleum hydrocarbons. <br /> C. Field Work <br /> In accordance with the work plan submitted to the San Joaquin County Environmental <br /> Health Department, four test borings were drilled at the project site during the Phase II <br /> investigation. At the completion of the drilling, one test boring (TB-3) was converted into <br /> a groundwater monitoring well. The approximate locations of the test borings and <br /> monitoring well is shown on Plate 2. <br /> The test borings and monitoring well were drilled and installed on December 14, 1990 by <br />' Bay Area Exploration (C-57 //522125). Boring logs and well construction profiles are <br /> presented on Plates A-2 through A-6.of Appendix A. A description of the Uniform Soil <br /> Classification System, which was used to describe the soils encountered in the test borings, <br /> PaSe 3 of 7 <br />