All objectives listed in Table 1.1, Sampling Rationale for December 2002, were accomplished. All wells scheduled to be sampled for the December event were sampled.

Sixteen wells of the 26 sampled wells reported detections of VOCs in December 2002. Of the wells with VOC detections, five wells had concentrations above the MCL for either PCE or TCE. Wells LS-2, LS-6, LS-7, RFR-10, and RFR-11 had detections of PCE above the MCL of 5.0 �g/L and well RFR-10 had a detection of TCE above the MCL of 5.0 �g/L. Wells LS-2 and LS-7 exceeded the MCL (5.0 mg/L) for PCE for the first time in December 2002. These five wells have all been equipped with GAC filtration systems.

Excluding wells listed above, three wells had detections at concentrations above the RL for one or more of the following analytes: PCE, TCE, chloroform, and dichlorodifluoromethane. Chloroform was detected in JW-14, PCE in LS-3, and PCE, TCE and dichlorodifluoromethane in OFR-3. Wells LS-3 and OFR-3 are equipped with GAC filtration systems.

Excluding wells listed above, eight wells reported results that were above the MDL, but below the RL (F-flagged) for one or more of the following analytes, PCE, TCE, cis-1-2-dichloroethene, chloroform, and dichlorodifluoromethane. These analytes were detected in wells HS-2, I10-2, LS-1, LS-4, LS-5, OFR-1, OFR-2, and RFR-12.

PCE concentrations decreased in December 2002 in wells I10-2, OFR-1, and OFR-2 and TCE concentrations decreased in wells I10-2, LS-1, and RFR-11.

PCE concentrations increased in wells HS-2, JW-14, LS-1, LS-2, LS-3, LS-4, LS-5, LS-6, LS-7, OFR-3, RFR-10, RFR-11, and RFR-12.

 TCE concentrations increased in wells LS-2, LS-3, LS-5, LS-6, LS-7, OFR-3, RFR-10 and RFR-12.

 Post-GAC samples were not collected during the December 2002 event. Post-GAC confirmation samples were collected in September 2002 from wells equipped with GAC filtration systems (LS-2, LS-3, LS-6, LS-7, OFR-3, RFR-10, and RFR-11). The results from post-GAC sampling confirm that the wellhead treatment systems are effectively removing VOCs from the drinking water.

Wells with detections above 90% of the MCLs (LS‑2, LS-3, LS-6, LS-7, OFR‑3, RFR-10, and RFR-11) will continue to be sampled on a quarterly basis, including the March 2003 event in accordance with Plan requirements.

Wells with detections of VOCs at less than 80% of the MCL (FO-J1, HS-2, I10-2, I10-4, JW-14, JW-26, LS-1, LS-4, LS-5, OFR-1, OFR-2, and RFR-12) will continue to be sampled on a quarterly basis, including the March 2003 event in accordance with Plan requirements. Depending on concurrence by regulatory agencies, the sampling frequency may then be reduced.

Post-GAC confirmation samples will be collected at all off-post wells with GAC systems during the March 2003 sampling event. This will include wells LS-2, LS-3, LS-6, LS-7, OFR‑3, RFR-10, and RFR-11.

For future sampling events, including March 2003, wells where no VOCs were detected may be sampled as needed. If, in the future, additional wells are located to the west and southwest of AOC‑65, they may be added to future sampling events. Future sampling events will continue to include wells to the west of CS-D and CS-MW16-LGR (Fair Oaks and Jackson Woods) to confirm they meet drinking water standards.

In accordance with project DQOs, the rationale for selection of wells to be sampled in March 2003 is provided in Table 4.1.