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Notes of Meeting on 28 February 1995 <br /> III groundwater investigation. <br /> Phase III Paula Bolio presented the objectives of Phase III. The objectives were 1) to <br /> Objectives further evaluate Zone C groundwater upgradient and downgradient of <br /> property, and 2)to collect groundwater data to support the evaluation of <br /> groundwater remedial action alternatives during the FS process. <br /> Data Collected Paula Bolio presented the components of the Phase III investigation. These <br /> components are described in detail in the Phase III Technical Memorandum. <br /> Groundwater Paula Bolio presented the present knowledge of Zones A, B, and C by zone. <br /> Results The main results of Phase III are: <br /> • Zone A will not sustain sufficient pumping rates. <br /> • Water levels have increased over time. <br /> • Groundwater flow direction in Zones A and B shows apparent shift from <br /> south to southeast in Zone A and from northeast to east in Zone B. <br /> • The clay layer separating Zones B and C includes interbedded sands. <br /> • Concentrations in Zone C are similar or higher than in onsite well MW-13. <br /> • Groundwater flow direction in Zone C appears to be to the east-southeast <br /> and the newly installed Zone C wells appear to be upgradient and <br /> crossgradient of the site. <br /> • The concentration of PNAs in groundwater has continued to decrease in <br /> Zones A and B since 1992. <br /> • The concentration of VOCs and TPH has decreased over time in the <br /> monitoring wells in Zone A near the former USTs. <br /> • Similar or greater PNA and benzene concentrations occur in upgradient <br /> and crossgradient Zone C wells than in the onsite Zone C well. <br /> Soil Results Paula Bolio presented results of all soil investigations by potential chemical of <br /> concern. <br /> • PNAs and petroleum hydrocarbons in soils are located primarily near the <br /> former tar sump and pit, the former lampblack separator, the former fuel <br /> Risk tanks and the former lampblack storage bin. <br /> Assessment <br /> Paula Bolio presented the results of the 1992 risk assessment for Areas I, II, <br /> and III. The Phase III results fit into the assumptions made during the risk <br /> assessment. <br /> • DTSC and RWQCB verbally presented PG&E with their comments on the <br /> 2 <br />