ARCHIVED REPORTS_XR0009603 - Laserfiche WebLink

Home Browse Search

Case Closure Report Former Tosco(Unocal)SS No 5421, Stockton,California July 8, 1998 residential and light commercial structures The site is characterized by topography that slopes very gently toward the southwest, and the site is located approximately 1,000 feet southeast of Five Mile Creek Site Background Underground Storage Tank Renlacement Activities Initial field work was conducted by Kaprealian Engineering, Inc (KEI) on November 17, 1989, when three underground storage tanks were removed from the site The tanks consisted of one 10,000 gallon super unleaded gasoline storage tank, one 10,000 gallon regular unleaded gasoline storage tank, and one 280 gallon waste oil tank The tanks were made of steel and no apparent holes or cracks were observed in any of the tanks Ms Kasey Foley of SJCPHS and Mr Ron Hiltscher of the City of Stockton Fire Department were present during tank removal Ms Foley was also present during subsequent soil sampling Four soil samples, labeled Al, A2, B1, and B2, were collected from beneath the fuel tanks at depths of 15 5 to 16 5 feet below grade One soil sample, labeled WO1 ,was collected from the soil beneath the waste oil tank at a depth of 9 5 feet below grade •1 Sample analytical results and locations are presented in Appendix A Tables IA and 2A, Figures IA, 2A and 3A KEI returned to the site on November 20, 1989, in order to collect soil samples from the product pipe trenches Four samples, labeled P1 through P4, were collected from the product pipe trenches Two samples, labeled VP1 and VP2, were collected from the vapor pipe trenches, and one sample, labeled WPI, was collected from the waste oil remote-fill pipe trench All seven soil samples were collected at depths ranging from 2 5 to 3 5 feet below grade Pipe trench sample analytical results and locations are presented in Appendix A Tables 1A and 3A, Figure 3A In an attempt to remove as much of the contaminated soil as possible in the vicinity of the fuel tank pit, KEI returned to the site on December 5, 1989, to observe additional soil excavation in the area of sample points A2 and B2, as described in KEI's work plan (KEI-P89-1104 Pl) dated November 22, 1989 Soil was excavated from the southerly half of the fuel tank pit (one of the additional samples was collected below sample point location A2 at a depth of 25 5 feet below grade, and the other additional sample was collected below sample point location B2 at a depth of 26 5 feet below grade, respectively) Four soil samples, labeled SW1(13), SW1(19), SW2(20/13), and SW2(20/19), were also collected from the fuel tank pit sidewalls at depths of 13 and 19 feet below grade Sample analytical results and locations are presented in Appendix A Table 1A, Figures IA & 2A Mr Harlin Knoll of the SJCPHS was present during . sampling 140162 03 2