Laserfiche WebLink
ERI <br /> ENVIRONMENTAL RESOLUTIONS, INC. <br /> June 3, 1997 <br /> ERI 205503 R01 <br /> Mr Adadu Yeniane <br /> Tosco Marketing Company <br /> 2000 Crow Canyon Place, Suite 400 <br /> San Ramon, California 94583 <br /> Subject Executive Summary, Supplemental Evaluation and Investigation Report, Unocal <br /> Service Station 5886, 2701 March Lane, Stockton, California <br /> Mr Yemane <br /> At the request of Tosco Marketing Company, (Tosco), Environmental Resolutions, Inc (ERI) <br /> performed a supplemental environmental investigation at the subject site ERI conducted the <br /> Investigation to evaluate the integrity of existing fuel systems and the extent of residual petroleum <br /> hydrocarbons in soil and dissolved petroleum hydrocarbons in groundwater beneath thesite ERI <br /> completed this work as part of implementation of ERI's Work Plan (dated March 27, 1997) and <br /> Addendum to Work Plan (dated April 3, 1997) which was approved by San Joaquin County Public <br /> Health Services Environmental Health Division on April 10, 1997 Specifically, the work included <br /> • Hand augering three on-site soil borings (HAI through HA3) in the vicinity of catch basins <br /> i <br /> located adjacent to dispenser islands, <br /> • Drilling four on-site soil borings (B4 through B7), and constructing duel completion <br /> groundwater monitoring wells MW4S through MW7S (shallow wells) and MW4D through <br /> MW7D (deep wells) in borings B4 through B7, <br /> • Collecting soil samples from the borings to evaluate soil stratigraphy, <br /> • Collecting and submitting soil samples for laboratory analyses for gasoline and diesel <br /> hydrocarbons and hydrogeologic parameters, <br /> • Developing newly installed wells, and, <br /> • Evaluating groundwater monitoring and sampling data provided by MPDS Services, Inc <br /> (MPDS) <br /> Results of the investigation indicate the following <br /> • Banks and Company did not note any leaks in the existing piping or in UST Interstitial spaces <br /> during their March 20, 1997 inspection Chromatograms are currently unavailable to evaluate <br /> whether methyl tert-butyl ether (MTBE) was present in groundwater prior to tank <br /> replacement <br /> • Sediments encountered in soil borings typically consisted of silty clay, clayey silt, and fine- <br /> grained sand <br /> 74 Digital Drive, Suite 6, Novato, California 94949 415-382-9105 (FAX 475-382-1856) <br /> Irvine • Novato - Seattle <br />