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March 2005 On-Post Quarterly Groundwater Monitoring Report

Section 5 - March 2005 Analytical Results

On-post groundwater sampling was performed March 7, 2005 � March 17, 2005. Thirty-three on-post wells were sampled using dedicated low-flow pumps: CS‑2, CS‑4, CS‑D, CS‑MWG‑LGR, CS‑MW1‑LGR, CS‑MW1‑BS, CS‑MW1‑CC, CS‑MW2‑LGR, CS‑MW2‑CC, CS‑MW3‑LGR, CS‑MW4‑LGR, CS‑MW5‑LGR, CS‑MW6‑LGR, CS‑MW6‑BS, CS‑MW6‑CC, CS‑MW7‑LGR, CS‑MW7‑CC, CS‑MW8‑LGR, CS‑MW8‑CC, CS‑MW9‑LGR, CS‑MW9‑BS, CS‑MW9‑CC, CS‑MW10‑LGR, CS‑MW10‑CC, CS‑MW11A‑LGR, CS‑MW11B‑LGR, CS‑MW12‑LGR, CS‑MW12‑BS, CS‑MW12‑CC, CS‑MW16‑LGR, CS‑MW17‑LGR, CS‑MW18‑LGR, and CS‑MW19‑LGR. Six wells, CS‑1, CS‑9, CS‑10, CS‑11, CS‑MW16‑CC and CS‑MWH‑LGR, were sampled using high capacity submersible pumps. One sample was collected from the windmill (CS‑I) that was equipped with a solar-powered submersible pump in September 2003. Samples were collected after field parameters stabilized. The Troll 9000 used in conjunction with the Rugged Reader to record field parameters would not calibrate before being deployed into the field. In lieu of this the YSI meter was used and parameters were recorded in the field logbook.

The analytical program for on-post monitoring wells includes short-list VOC analysis for bromodichloromethane, bromoform, chloroform, dibromochloromethane, dichlorodifluoromethane, 1,1‑dichloroethene (DCE), cis‑1,2‑DCE, trans‑1,2‑DCE, methylene chloride, naphthalene, PCE, TCE, toluene, and vinyl chloride. Samples from the drinking water supply wells (CS‑1, CS‑9, and CS‑10) were analyzed for the full list of VOCs, as well as nine metals. On-post monitoring wells are analyzed for metals once annually. The June 2005 event is the next scheduled annual sampling for metals, including arsenic, cadmium, lead, barium, chromium, copper, nickel, zinc, and mercury. These nine metals were chosen based on CSSA�s waste disposal records and process knowledge. As part of the March 2005 sampling event on-post monitoring wells were analyzed for the short list of VOC analytes.

Parsons data package numbers TO 0008 #119 through #123 containing the analytical results from this sampling event were received by Parsons from March 22, 2005 to March 31, 2005. Data validation was conducted and submitted to AFCEE on April 25, 2005. AFCEE approved the data packages on May 12, 2005. All detected concentrations of VOCs are presented in Table 5‑1. Full analytical results are presented in Appendix B. Cumulative analytical results can be found in Tables 6 and 7 of the Introduction to the Quarterly Groundwater Monitoring Program (Parsons, 2001) (Volume 5, Groundwater).

5.1 - Volatile Organic Compound Results

5.1.1   MCL Exceedances in Monitoring Wells

MCLs were exceeded in wells CS‑MW16‑LGR (formerly well CS‑16), CS-MW16-CC, CS‑MW1‑LGR and CS‑D in the March 2005 event. The detected concentrations are summarized as follows:

Wells in which the contaminants of concern (COC) exceed MCLs were plotted for concentrations over time and are shown in Figure 5-1. Well CS‑MW16‑CC, installed December 20, 2002, does not have results from 1998 through 2002. CS‑MW16-LGR concentrations from the March 2005 event increased since December 2004. In March 2005 concentrations in well CS‑D decreased and are still below the maximum detection that occurred in December 2003. In March 2005 the concentrations in well CS‑MW2‑LGR remained below MCL while concentrations in well CS-MW1-LGR decreased. A remedial process optimization study is being conducted for the CSSA groundwater monitoring program. This study will evaluate sampling frequency and analyte lists. The preliminary statistical evaluation is being conducted.

5.1.2   Toluene and Methylene Chloride Detections

Methylene chloride has been reported periodically in samples from both on- and off-post wells since 1992. Each time methylene chloride was detected, it was also present in the analysis method blank, indicating the analyte was introduced as a laboratory contaminant and was not present in the groundwater. Methylene chloride is considered a common laboratory contaminant and there are no known historical uses of methylene chloride on-post. Methylene chloride was not detected in any samples during the March 2005 sampling event.

Toluene was detected in the March 2005 sampling event at concentrations ranging from 0.25 �g/L to 0.89 �g/L. These levels were below the applicable maximum contaminant level (MCL) for toluene in drinking water (1,000 μg/L). Toluene has been detected sporadically in on-post wells since March 2003.

5.1.3   Detections Below the MCL in Monitoring Wells

Additional wells had detections of COCs below applicable MCLs. These wells are monitoring wells installed as part of the ongoing groundwater investigation. Detections of methylene chloride and/or toluene are not discussed as additional information has been provided previously in Section 5.1.1.

Well CS-4 reported PCE at a concentration of 1.1 �g/L, which was below the applicable RL. Also detected were TCE (2.2 �g/L) and cis-1,2-DCE (1.5 �g/L), above the RL. PCE and TCE have been detected in this well since 1992. June 2004 was the first time concentrations have exceeded the applicable MCLs. The field duplicated reported similar results in well CS‑4.

Wells CS-MWG-LGR and CS-MWH-LGR reported no VOC detections this quarter. Well CS‑2 also had no VOC detections this quarter. This is the second event for well CS-2 without a PCE and/or TCE detection since March 2003.

CS‑MW1‑BS had a detection of cis-1,2‑DCE (0.29 �g/L), below the RL. Toluene was also detected below the RL at a concentration of 0.89 �g/L. This is the second event since September 2003 that TCE has not been detected in this well. Well CS‑MW1-CC had no VOC detections in March 2005.

CS-MW2‑LGR had a detection of cis‑1,2-DCE at a concentration of 4.1 �g/L, above the RL. Well CS‑MW2‑CC was sampled for the eighth time this quarter. The well had no VOC detections in March 2005.

Wells CS-I, CS‑MW3‑LGR, CS-MW4-LGR, and CS-MW4-LGR field duplicate reported no VOC detections in March 2005. Well CS-MW3-LGR had PCE and TCE detections in September 2003, both below the RL. Well CS-I had a toluene detection below the RL in September 2003, but has had no VOC detections since that event.

CS‑MW5‑LGR had detections of PCE, TCE, and cis-1,2-DCE, at concentrations of 0.82 �g/L, 1.0 �g/L, and 1.2 �g/L, respectively. TCE and cis-1,2-DCE were above the RL while PCE was below the applicable RL.

In March 2005 wells CS‑MW6‑LGR, CS‑MW6‑BS, CS‑MW6‑CC, CS‑MW7-LGR, and CS-MW7-CC had no VOC detections. The CS-MW6 cluster has had two occurrences of PCE and/or TCE since the wells were installed in September 2001. The CS-MW7 cluster has had sporadic detections, however PCE and/or TCE has not been detected in these wells since March 2004.

Well CS‑MW8‑LGR had a detection of PCE at a concentration of 0.62 �g/L, below the RL. PCE has been reported in this well since sampling began in June 2001, with the exception of December 2003. All concentrations have been below the RL. PCE was detected for the third time in well CS‑MW8‑CC (0.43 �g/L), below the RL, in March 2005. CS‑MW8‑CC has been sampled quarterly since June 2001.

Wells CS‑MW9‑LGR, CS-MW9-BS, and CS-MW9-CC had no VOC detections in March 2005. CS-MW9-LGR has had sporadic PCE detections in March 2002 and in most of the 2003 monitoring events. CS-MW9-BS and CS-MW9-CC have never had PCE and/or TCE detections.

CS‑MW10‑LGR had detections of PCE and TCE at concentrations of 2.3 �g/L and 0.38 �g/L, respectively. PCE was above the RL but below the MCL while the TCE was below the RL. Well CS-MW10-CC had no VOC detections in March 2005.

Well CS‑MW11A‑LGR was sampled for the eighth time in March 2005. Well CS‑MW11A‑LGR reported a detection of PCE (0.28 �g/L) below the RL. Well CS‑MW11B‑LGR reported a detection of PCE at a concentration of 1.2 �g/L, which is below the RL. This is the sixth sample collected from this well since it was installed in June 2003. PCE has been consistently reported below the RL in CS-MW11B-LGR.

No VOCs were detected in CS‑MW12‑LGR in March 2005. CS‑MW12‑BS had detections of naphthalene and vinyl chloride at concentrations of 0.35 �g/L and 0.30 �g/L, both below applicable RLs. CS‑MW12‑CC had a detection of toluene (0.34 mg/L), below the RL.

PCE was detected in well CS‑MW17‑LGR at a concentration of 0.27 �g/L, below the RL. Well CS‑MW18‑LGR reported no VOC detections this quarter. PCE was first detected at a concentration of 0.051 �g/L in September 2004. CS‑MW18-LGR has been sampled quarterly since September 2002. Well CS‑MW19‑LGR had a detection of PCE (0.23 �g/L), below the RL. PCE has been consistently detected below the RL in wells CS-MW17-LGR and CS‑MW19-LGR since they were installed in September 2002.

5.1.4   Drinking Water Supply Well Results

Drinking water supply wells are analyzed for the full list of VOCs. Current and former drinking water supply wells for CSSA sampled in March 2005 were CS‑1, CS‑9, CS‑10, and CS‑11. All contaminant concentrations detected in these wells were below MCLs.

CS‑1 had no VOC detections in March 2005. In past events, PCE and TCE concentrations have remained constant with sporadic detections of chloroform, methylene chloride and toluene.

Well CS-9 had no VOC detections in March 2005. There have been five detections of PCE since the well was first sampled in August 1991. All detections have been below the RL.

Well CS‑10 had a detection of chloroform at a concentration of 0.19 �g/L, below the RL. Well CS-11 had no VOC detections nor did its field duplicate.

5.2 - Metals Analyses

All drinking water wells were analyzed for the metals arsenic, cadmium, lead, barium, chromium, copper, nickel, zinc, and mercury in March 2005. In March 2005, no drinking water wells had results above the appropriate MCL, action level (AL), or secondary standard. The next annual post-wide sampling event for metals will be conducted in June 2005.

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