SITE INFORMATION AND CORRESPONDENCE 1993-1995

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Notes of Meeting on 28 February 1995 Topic: Proposed Revisions to Groundwater Monitoring Program Item Discussion Monitoring Paula Bolio presented proposed revisions to the 1995 groundwater monitoring Program program. These revisions included 1) sampling new wells quarterly, 2) sampling previously installed perimeter wells annually, 3) not sampling inner wells MW4, MW-8, and MW-5, 4) analyzing groundwater samples for PNAs and BTEX compounds. Barium and antimony would analyzed for one time only and cyanide would be analyzed for wells MW-9 and MW-19 one time. Discussions about the proposed monitoring program led to the following modifications: • Interior monitoring wells;MW-4 (A Zone), MW-5 (B Zone), MW-8 (A Zone) and MW-13 (C Zone), will be monitored semi-annually(March and September schedule). • All other monitoring wells(perimeter and newly installed wells) will be monitored quarterly. • Monthly groundwater level measurements will be collected for six months. The need to continue monthly water level measurements thereafter will be evaluated • One round of TPH(diesel and gasoline), barium and antimony, and cyanide for wells MW-9 and MW-19 will be performed in March 1995. The need to continue monitoring for these wells thereafter, will be evaluated Wendy Cohen mentioned that the odor threshold for gasoline and diesel is fairly low(e.g. 100 ppb for diesel and 5 ppb for gasoline). Therefore, they suggested that the detection limit for TPH-gasoline be lowered • Quarterly monitoring reports are to be submitted one month after the end of the quarter. Topic: Schedule Item Discussion Activities/ Paula Bolio presented the near-term schedule which originally included a Schedule PG&E response to agency comments on the Technical Memorandum on March 14, 1995 and delivery of the draft Feasibility Study to DTSC on April 28, 1995. • It was agreed that a final Technical Memorandum would be submitted to 4