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September 2001 Off-Post Quarterly Groundwater Monitoring Report
Section 3 - September 2001 Groundwater Sampling Procedures
The quarterly off-post groundwater monitoring was performed September 17 through September 20, 2001. Two additional wells were sampled September 27, 2001. Off-post wells sampled during the initial quarterly monitoring event were selected based on proximity to known VOC source areas and the post boundary. Results from previous monitoring events were also considered during the selection of wells to be sampled. Public supply and private wells located west and south of CSSA were selected for the initial round of quarterly sampling. Figure 1.1 illustrates the locations of off-post private and public wells sampled during the September 2001 quarterly event.
One private well was sampled from the Dominion area, which is located directly south of CSSA (DOM-2). Two public supply wells were sampled in the Fair Oaks area (FO-22 and FO-J1). These wells are located southwest of the SWMU B-3 andO-1 source areas, but north-northwest of the Building 90/AOC 65 site Five privately-owned wells were sampled in the Jackson Woods subdivision (JW-6, JW-9, JW-12, JW-13, and JW-14), located west of CSSA and just south of Fair Oaks. One well was sampled in the I-10 area (I10-2), which is southwest of CSSA and west of the suspected source area at AOC 65. Six wells in the Leon Springs area were sampled, four public wells, LS-1, LS-2, LS-3, and LS-4, and two privately-owned wells, LS-6 and LS-7. LS-2 and LS-3 were sampled after the quarterly event conducted the week of September 17, 2001. Leon Springs is located south of CSSA and the suspected contaminant source at AOC 65. Five wells were sampled in the Ralph Fair Road area (RFR-6, RFR-7, RFR-8, RFR-9, and RFR-10), located west of CSSA. In total, twenty off-post wells were sampled during September 2001 (Figure 1.1). Wells LS-2, LS-3, and RFR-10 were sampled from September 27 through October 12, 2001.
All wells were sampled from a tap installed by CSSA as close to the wellhead as possible to obtain a representative sample before pressurization or storage and before it enters the water supply distribution system. Taps were installed the week of September 3, 2001 on privately-owned wells RFR-8, JW-9, JW-12, JW-14, JW-13, RFR-6, RFR-9, RFR-7, DOM-2, and I10-2. JW-6 was fitted with a tap on September 19, 2001. Wells LS-4, LS-1, FO-22, FO-J1, and RFR-10 had existing taps at the wellhead. Because LS-6 and LS-7 have GAC units installed, samples were collected before (PRE) and after (POST) treatment. Prior to sample collection, water was flushed to engage the well pump. While the well was pumping, the pH, conductivity, and temperature readings were recorded to confirm adequate purging. When these parameters stabilized, in accordance with the FSP located in the Environmental Encyclopedia, Volume 1-4, the groundwater samples were collected. Field notes including well purging data are included in Appendix D.
Each groundwater sample collected was analyzed for VOCs using SW846 Method 8260B by APPL Laboratory in Fresno, California. Eighteen groundwater samples, two field duplicate samples, one MS/MSD pair, and one trip blank were submitted to APPL. The Parsons internal data package DO5084 #10 contains the analytical results for this sampling event. Laboratory results were reviewed and verified according to the guidelines outlined in the AFCEE QAPP, version 3.0. The data package was received by Parsons on October 11, 2001, and submitted to AFCEE on December 18, 2001 where it was placed in line for priority review. This data package was approved by AFCEE in January 2002.