Laserfiche WebLink
San Joamuin County Environmental Health Division <br />June 20, 2008 <br />Page 2 <br />discarded equipment and containers. The Phase I ESA noted that the Westway facility <br />and adjacent properties located north and southeast of the Site formerly contained <br />underground storage tanks (USTs) filled with petroleum products. The Phase II <br />investigation conducted by IT Corporation in 1991 did not detect elevated <br />concentrations of pH, hydrocarbons, benzene, toluene, ethylbenzene and xylenes <br />(BTEX), chloride and nitrate in the soil and groundwater samples collected. The Phase <br />II investigation did include a subsurface geophysical survey, which identified one <br />significant magnetic anomaly. The exact location of this anomaly is currently unknown <br />and further investigations of the anomaly does note appear to have been performed. <br />The Phase I ESA report presented supplemental information regarding the investigation <br />and remediadon of Koppel Stockton Terminal (Koppel) located adjacent to the <br />southeast boundary of the Site, including a copy of the Five-Year Evaluation and 2006 <br />Annual Groundwater Monitoring Report, prepared by CH2MHill, dated October 2006. <br />The Koppel site has been undergoing routine groundwater monitoring and <br />phytoremediation for the constituents of concern Total Kjehldahl Nitrogen (TKN), <br />nitrate as nitrogen, ammonia as nitrogen, pH and total dissolved solids (LOS). The <br />investigation and remediation of the Koppel site is being overseen by the Central Valley <br />Regional Water Quality Control Board (RWQCB) and includes four monitoring wells <br />that are located on the USBG Site. The Koppel investigation indicated that groundwater <br />elevations fluctuate seasonally, ranging from approximately 5 to 12 feet below ground <br />surface (bgs), and was determined to flow toward the south to southeast; however, the <br />1991 Phase II investigation indicated that groundwater underlying the Site flows <br />towards the north. <br />Phase II Investigation <br />BC will perform a Phase II investigation as presented below. The objective of the <br />subsurface investigation activities is to provide REG/USBG data on the existing <br />conditions at locations of potential concern. This Phase II investigation was developed <br />based on the information gathered during the previous environmental investigation of <br />the Site and the adjacent Koppel property. <br />Task 1. Pre-field Activities <br />Prior to performing the investigation's field sampling activities, BC will perform the <br />following: <br />Notify Underground Service Alert (USA) of the pending drilling activities. <br />Contract a California C-57 licensed driller, a private subsurface utility locator, and <br />a California Department of Health Services certified analytical laboratory. <br />P:035000 \ 135531-USIMG Phase II InvesFtnal Documents \Final REG Phase II Work Plan 052808.doc1dt