SITE INFORMATION AND CORRESPONDENCE 1995-2004

Home Browse Search

James L. Tjosvold, P.E. January 24, 1997 Page 3 II. Activities Performed During Current Quarter: On October 10, 1996, PG&E submitted its"Workplan for Additional Soil and Groundwater Investigation during the Feasibility Study" to DTSC and the RWQCB. This Workplan included additional soil borings in Area I; conducting DI WET and TCLP analyses on selected soil samples from Area I; the drilling of soil borings in Area II; and the installation of a Zone B groundwater monitoring well(s) at the perimeter of Area H. A final Workplan, revised to reflect comments received during an October 30, 1996 conference call between PG&E, DTSC and the RWQCB, was submitted to the agencies on November 13, 1996. This final Workplan was approved by DTSC on November 15, 1996. The field work for the additional soil and groundwater investigation approved by DTSC in November, 1996 took place between December 9, 1996 and December 20, 1996. Activities included: 1) drilling six soil borings in Area I to further define Source Areas 2 and 4, including the drilling of two additional borings beyond the four planned borings (these additional borings were determined to be needed based upon field observations) and drilling one soil boring to collect a sample from Source Area 2 for DI WET and TCLP analyses; 2) the installation of six soil borings in Area II, including three borings within the footprint of the former auto repair facility, two borings around a previous boring (MW-22R)which contained hydrocarbons in the groundwater and one boring outside the substation yard upgradient of Area II; and 3) the installation of a B Zone well along El Dorado Street (MW-26). Based upon field observations in Area II, it was determined that additional A and B zone wells were not needed. Soil borings were analyzed for PNAs, TPH-diesel, TPH-gasoline and BTEX(Area II soils were also analyzed for chlorinated solvents). In addition, three soil samples from Area I (one from Source Area 2 and two outside the source areas)were analyzed by DI WET for PNAs and TPH-diesel and by TCLP for TPH-gasoline and BTEX. Hydropunch samples were taken from the A Zone and the B Zone during the drilling of the new B Zone well (MW-26) and a groundwater sample was taken from the newly installed B Zone well (MW-26). These samples were analyzed for PNAs, TPH-diesel, TPH-gasoline and BTEX. The analytical results of this soil and groundwater investigation will be sent to the agencies prior to a conference call scheduled for February 13, 1997 to discuss the results of this soil and groundwater investigation. Quarterly groundwater monitoring was conducted in December, 1996. The results of this groundwater monitoring will be submitted to the agencies by January 31, 1997 in the "Quarterly Monitoring Report, PG&E Stockton Former MGP Site, Fourth Quarter 1996".