SITE INFORMATION AND CORRESPONDENCE 1993-1995

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James L. Tjosvold, P.E. July 12, 1995 Page 2 At the February 28, 1995 meeting, PG&E also briefly presented for discussion a preliminary remediation approach for this site that PG&E plans to incorporate into the Feasibility Study. The approach includes remediation of soils with higher levels of contamination to eliminate them as potential sources of groundwater degradation and continuation of groundwater monitoring to demonstrate that natural groundwater attenuation is occurring. At the meeting, DTSC and the RWQCB requested that PG&E install additional groundwater monitoring wells to further define the groundwater plume, in particular, to delineate the nondetect groundwater contour. PG&E agreed to submit to DTSC and the RWQCB a Phase IV Groundwater Investigation Work Plan identifying additional groundwater monitoring wells. The purpose of the Phase IV Work Plan will be to identify well locations at the edge of the groundwater plume. PG&E also agreed to take monthly groundwater level measurements to determine the groundwater flow gradient in A, B and C Zones for the next six months. In addition, the groundwater monitoring program was modified at the meeting. On March 14, 1995, PG&E submitted the"Final Phase III Technical Memorandum, Stockton Former Manufactured Gas Plant Site, Pacific Gas and Electric Company", to DTSC and the RWQCB. This final Technical Memorandum incorporates DTSC and RWQCB comments on the January, 1995 Technical Memorandum. The first round of groundwater sampling for 1995 occurred on March 13-14, 1995. The quarterly monitoring report containing the results of this groundwater monitoring round was submitted to DTSC on May 8, 1995. II Activities Performed During Current Quarter: On April 24, 1995, PG&E and DTSC conducted a conference call to discuss DTSC and RWQCB comments on PG&E's final Phase III Technical Memorandum (submitted to PG&E in a letter dated April 12, 1995). During the conference call, PG&E and DTSC agreed that installation of additional groundwater monitoring wells should be postponed until PG&E had collected at least six sets of monthly groundwater elevation measurements (a workplan to install additional wells had been scheduled for submittal on April 25, 1995). PG&E was requested to separate the soil and groundwater efforts to allow progress on soil remediation without waiting for further groundwater investigation. In response to this conference call, PG&E submitted a revised work scope and project schedule to DTSC on May 1, 1995. In the May 1, 1995 letter PG&E agreed to separate the soil and groundwater into two operable units and to proceed with separate Feasibility Studies (FS's) and Remedial Action Plans (RAP'S) for each operable unit.