SITE INFORMATION AND CORRESPONDENCE 1993-1995

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James L. Tjosvold, P.E. October 13, 1995 Page 2 As part of the soil FS process, PG&E plans to further characterize the extent and nature of manufactured gas plant and underground tank residues in identified source areas at the site. In preparation for this, on June 12, 1995, PG&E submitted to DTSC a workplan for performing supplemental soil investigation at the site. The proposed soil investigation consisted of drilling a minimum of twenty one soil borings to a depth of 25 feet and collecting approximately four soil samples from each soil boring. Both field and laboratory analysis were to be performed to determine the concentration of polynuclear aromatic hydrocarbons (PNAs) and total petroleum hydrocarbons in the soil. The soil investigation, as outlined in the workplan, began on June 28, 1995 and was completed on July 5, 1995. On May 8, 1995, PG&E submitted its response to DTSC's and the RWQCB's April 12, 1995 comments on the final Phase III Technical Memorandum. On May 12, 1995, PG&E submitted minutes for the February 28, 1995 meeting between PG&E, DTSC and the RWQCB, "The Quarterly Monitoring Report, PG&E Stockton Former MGP Site, First Quarter, 1995" was submitted to DTSC and the RWQCB on May 8, 1995. The second quarterly groundwater monitoring was conducted during the week of June 5, 1995. (The results of this second quarterly groundwater monitoring were submitted to DTSC and the RWQCB on July 28, 1995.) Monthly water level measurements of all wells was conducted. II. Activities Performed During Current Ouarter: The supplemental soil investigation, which was conducted in accordance with the June 12, 1995 workplan began on June 28, 1995 and was completed on July 5, 1995. During the investigation, twenty-four soil borings were drilled to a depth of approximately 25 feet (unless refusal was encountered) and 62 samples were collected. Both field analyses (using Handby test kits) and laboratory analysis were performed to determine the concentration of PNAs and total petroleum hydrocarbons in the soil samples. Soil samples were also analyzed for benzene, toluene, ethylbenzene and xylene in the laboratory, and 25 soil samples were analyzed for additional parameters in the laboratory(pH, cyanide, sieve analysis, moisture content and total organic carbon). The results of this supplemental soil investigation will be included in the soil operable unit FS being prepared for this site. On August, 17, 1995, PG&E submitted to DTSC its proposed remedial action objectives for the Stockton project. These proposed remedial action objectives and goals were to be used to develop and evaluate possible alternatives in the soil operable unit FS. In the