MCLs were exceeded for one or more of PCE, TCE, and cis-1,2-DCE, in wells CS‑MW16‑LGR (formerly well CS-16), CS-MW16-CC, CS-MW1-LGR, and CS-D.

Monitoring wells CS-4, CS-4 field duplicate, CS-MW2-LGR, CS-MW5-LGR, and CS‑MW10-LGR had detections of COCs at concentrations below applicable MCLs but above the RL (Table 6-1).

Monitoring wells CS-2, CS-I, CS-MWG-LGR, CS-MWH-LGR, CS-MW1-CC, CS‑MW2‑CC, CS-MW3-LGR, CS-MW4-LGR, CS-MW4-LGR field duplicate, CS-MW6-LGR, CS-MW6-BS, CS-MW6-BS field duplicate, CS-MW6-CC, CS‑MW7-LGR, CS-MW7-CC, CS-MW9-LGR, CS-MW9-BS, CS‑MW9-CC, CS‑MW10-CC, CS-MW12-LGR, and CS-MW18-LGR had no VOC analytes detected above either the applicable MDL or RL.

Drinking water wells CS-1 and CS-9 had no VOC detections in March 2005.  Well CS-10 had a detection of chloroform below the RL.

Plume maps showing PCE, TCE and cis-1,2-DCE detections for the LGR, CC, and BS are illustrated in Figure 6.1 through Figure 6.7.

The LGR groundwater potentiometric surface map (Figure 2-1) for March 2005 shows groundwater flow to be variable throughout the facility and generally to the east and southeast.

The LGR potentiometric surface map near Building 90 indicated a groundwater flow to the southeast and southwest, and the CC potentiometric surface map near Building 90 indicated a groundwater flow to the east in March 2005.

In March, 2005, vinyl chloride was detected in well CS-MW12-BS.  Historical vinyl chloride detections include:

Metals were sampled in March 2005 in drinking water wells and no concentrations exceeded the applicable MCLs and/or AL.

An average decrease in water levels of 6.47 feet occurred between December 2004 and March 2005.  Between December 3, 2004, and March 7, 2005, WS-N reported 7.38 inches of rain and WS-S measured 6.48 inches of rain.

The CS-WB02-LGR-02 zone is historically dry during sampling and was able to be sampled this quarter.  PCE and TCE were detected.