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emora n d u m CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD e CENTRAL VALLEY REGION 3443 Routier Road Phone: (916) 361-5600 Sacramento, CA 95827-3098 ATSS: 8-495-5600 TO: KENNETH D. LANDAU FROM: Wendy L. Cohen Senior Engineer Project Engineer DATE: 5 June 1987 SIGNATURE: L SUBJECT: REVIEW OF GROUND WATER MONITORING REPORTS, UNIVERSITY OF CALIFORNIA, LAWRENCE LIVERMORE NATIONAL LABORATORY SITE 300, SAN JOAQUIN COUNTY I have reviewed two ground water monitoring reports for the fourth quarter 1986 and first quarter 1987 submitted by Lawrence Livermore National Laboratory (LLNL) on 23 February and 21 May 1987, respectively, for ongoing monitoring at Site 300. My comments follow: 1. Both reports still contain unexplained symbols, dashes, and blank spaces in the tables containing data. For example, in the February 1987 report, Tables Al and A4 contain dashes and in the May 1987 report, Tables Al, A2, and A4 contain the symbols "TBA" and "NA" and Table A2 contains dashes. These symbols and dashes need to be explained. Also the symbol "NO" for "non-detectable" should be accompanied by the detection limit achieved. 2. Both reports contain statistical analyses for data from Pit 1 and from the high explosives surface impoundment (called 817) . The analysis in the February 1987 report used the first four quarters of sampling in each case from the upgradient wells as background. For Pit 1, LLNL used the fourth quarter 1985 through third quarter 1986 as background, and for 817 the second quarter 1985 through first quarter 1986. In this analysis, they correctly compared subsequent quarters of data from downgradient wells to the respective background values, resulting in findings of statistically significant increases in several parameters for both Pit 1 and 817. LLNL discounted the significance at 817 based on a variety of explanations. In the May 1987 report, another statistical analysis was performed, but was not done correctly. Background was calculated based on the four quarters of 1986 for both Pit 1 and 817 which is a different background than used in the previous report. Also, the downgradient data from the first quarter 1987 was incorrectly compared to first quarter 1987 data from the up- gradient wells instead of to upgradient background. Statistical analyses are needed for both Pit 1 and 817 using a justifiable background period (this does not have to be limited to four quarters but should have a logical basis) . Once background is calculated, it does not change, and each quarter, the downgradient data is compared to the same background. Once the new analyses are complete, we will determine the need for a ground water quality assessment program (Pit 1) or verification monitoring (817).