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Investigation Activities <br /> ERM-West was then further retained by Catellus Development <br /> Corporation to investigate the extent of the release at Site #2 and to <br /> assess the need for remediation Two phases of additional <br /> investigation have been conducted by ERM-West to assess the extent of <br /> the release and evaluate the need for remediation The Phase I <br /> investigation conducted in March 1992 included the installation of four <br /> ground water monitoring wells (MW-1A through MW-4A) and the <br /> collection of soil samples from the monitoring well borings The <br /> locations of the four ground water monitoring wells constructed at the <br /> site during the Phase I investigation are illustrated on Figure 3-4 <br /> In addition, in December 1992, a geophysical survey was conducted at <br />' Site #2 to identify the potential presence of any buried objects which <br /> could represent another source for a release of chemicals to soil or <br /> ground water The survey was performed using both a magnetometer <br /> and ground penetrating radar to locate the potential presence of buried <br /> objects and/or debris at the site The survey investigated a 150-foot by <br /> 150-foot area which covered the entire site investigation area north of <br /> the warehouse building (including all boring locations except MW-4A <br /> inside the warehouse) and extended to the edge of the Stockton Deep <br /> Water Channel The results of the investigation found no anomalies <br /> characteristic of buried objects or debris over the entire survey area <br /> The Phase II investigation conducted in April 1993 consisted of the <br /> installation of one additional monitoring well (MW-5A) and four soil <br /> borings Detailed descriptions of the two phases of investigation are <br /> provided in the PAR <br /> Sample AnalyNis <br /> Selected soil samples and ground water samples from the first phase of <br /> the investigation were analyzed for the following constituents <br /> • TPH as gasoline and diesel, <br /> • Total Lead, <br /> • Organic Lead, and <br /> • EDB <br /> For QA/QC purposes during the ground water sampling, field blanks <br /> and trip blanks were collected and analyzed for TPH as gasoline and <br /> 3-4 <br />