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June 2001 On-Post Quarterly Groundwater Monitoring Report
Section 4 - June 2001 Analytical Results
Groundwater sampling was performed June 11 through June 15, 2001. Twenty-two onsite wells were sampled: 1, 2, 9, 10, 16, D, G, H, I, MW1-LGR, MW2-LGR, MW3-LGR, MW4-LGR, MW5-LGR, MW6-LGR, MW6-BS, MW6-CC, MW8-LGR, MW8-CC, MW9-LGR, MW9-BS, and MW9-CC. In addition, one offsite well, Well LS-7, was sampled.
Wells G, H, MW6-LGR, MW6-BS, and MW6-CC were sampled with a bailer during this sampling event. Bladder pumps had not yet been installed in the MW6 cluster wells as of June 2001. The samples from Wells MW8-LGR and MW8-CC were collected with a gasoline-powered submersible pump that was being used to develop these wells during this sampling event.
Groundwater sampling was affected by two separate problems during the June 2001 sampling event. Well 11 could not be sampled during this event because the pump controller was not operational. In addition, bladder pumps in several of the newly installed monitoring wells were not functioning correctly at the time of sampling. The bladder pumps malfunctioned in Wells MW3-LGR, MW4-LGR, MW5-LGR, MW9-LGR, MW9-BS, and MW9-CC because their bladders became partially disconnected while pumping as a result of defective bladders. The partially detached bladder allowed air to enter the pump tubing and aerate the sample. VOC analytical results for samples affected by this problem may be impacted because VOC concentrations could be reduced by the aeration.
The analytical program for on-post wells was revised from previous groundwater testing protocols to include only metals and VOCs. For initial sampling at a newly installed monitoring well, groundwater was also tested for cations and anions. The data packages DO5084-8 and DO5084-9 contain the analytical results for this sampling event.
The data packages were received by Parsons on July 13, 2001, and subsequently validated and submitted to AFCEE on August 7, 2001. All of the detected concentrations of cations, anions, metals and VOCs are presented in Table 2. Full analytical results for June 2001 are presented in Appendix B. Historical VOC and metals data can be found in Tables 6 and 7, respectively, of the Introduction to the Quarterly Groundwater Monitoring Program at CSSA (Parsons ES 2001).
4.1 - Volatile Organic Compound Analyses
A group of newly installed monitoring wells that was sampled for the first time during this event included Wells MW3-LGR, MW4-LGR, MW5-LGR, MW6-LGR, MW6-BS, MW6-CC, MW8-LGR, MW8-CC, MW9-LGR, MW9-BS, and MW9-CC. The only VOC concentrations above the RL identified in these wells occurred in Well MW5-LGR with cis-1,2-DCE at 1.90 �g/L and TCE at 1.70 �g/L. Both of these concentrations are well below their MCLs of 70 �g/L and 5�g/L, respectively.
Several new monitoring wells exhibited sub-RL VOC concentrations. Wells MW5-LGR and MW8-LGR both had a PCE concentration of 1.10 �g/L. Well MW8-LGR also had a TCE concentration below the RL at 0.18 �g/L. Well MW6-LGR was found to have a cis-1,2-DCE concentration of 0.26 �g/L, a PCE concentration of 0.50 �g/L, and a TCE concentration of 0.42 �g/L. Sub-RL concentrations of toluene were detected in Wells MW6-BS and MW6-CC at concentrations of 0.34 �g/L and 0.43 �g/L, respectively.
MCLs for TCE, PCE, and cis-1,2-DCE were exceeded in Well 16 during the June 2001 sampling event. The PCE concentration was 75.00 �g/L, the TCE concentration was 73.00 �g/L, and the cis-1,2-DCE concentration was 73.00 �g/L. The concentrations of these compounds in Well 16 decreased from the levels found during the March 2001 monitoring event. The March 2001 levels of PCE, TCE, and cis-1,2-DCE were 125.68 �g/L, 150.60 �g/L, and 141.18 �g/L, respectively. Chloroform and trans-1,2-DCE, which had been previously found in Well 16, were not detected during this event.
The TCE (140.0 �g/L), PCE (110.0 �g/L), and cis-1,2-DCE (130.0 �g/L) concentrations in Well D were above MCLs. The March 2001 levels of TCE (91.4 �g/L), PCE (63.55 �g/L), and cis-1,2-DCE (77.73 �g/L) in Well D were somewhat lower than the results from this monitoring event. Well D also had a trans-1,2-DCE concentration of 0.94 �g/L and chloroform was detected below the RL at 0.17 �g/L during this event.
The concentrations of PCE, TCE, cis-1,2-DCE, and trans-1,2-DCE in Well MW1-LGR were 21.00 �g/L, 30.00 �g/L, 27.0 �g/L, and 0.27 �g/L, respectively. Except for trans-1,2‑DCE, the concentrations of these compounds remained relatively unchanged from March 2001 levels of 24.56 �g/L, 27.8 �g/L, 27.2 �g/L, and 2.55 �g/L, respectively. The PCE and TCE MCLs were exceeded in Well MW1-LGR.
PCE and TCE concentrations were above the MCLs in Well MW2-LGR at 7.10 �g/L and 6.50 �g/L, respectively. A cis-1,2-DCE concentration of 4.63 �g/L was also identified. The compound trans-1,2-DCE was not detected in this well.
The water supply wells, Wells 1, 9, and 10, did not have any VOC concentrations that exceeded the RL. Off-post Well 1 had a sub-RL TCE concentration of 0.19 �g/L which is very similar to the March 2001 level of 0.2 �g/L. PCE was not found in Wells 9 and 10 during this monitoring event after being detected for the first time in these wells in March 2001. Well 10 had a chloroform detection at 0.26 �g/L. Well 9 had no VOC detections. As mentioned previously, Well 11 was not sampled due to a malfunctioning pump controller.
Several occurrences of metals concentrations exceeded MCLs during this monitoring event. Most notably, Well I, which is equipped with a windmill driven sucker rod apparatus, exhibited a zinc concentration of 3470 mg/L. This result is much higher than previous zinc levels in this well. The zinc results for this well will be compared to the September sampling event results to determine if this measurement is reliable. Well I exhibited a lead concentration of 0.0349 mg/L, which exceeds the AL (action level) of 0.015 mg/L.
The term action level is used here because EPA�s Safe Drinking Water Standards list action levels only (no MCLs) for lead and copper. According to 40 CFR 141.2, action level is defined as the concentration of lead or copper in water specified in 40 CFR 141.80(c) which determines, in some cases, the treatment requirements that a water system is required to complete.
The lead AL was also exceeded in Well H and Well MW3-LGR, which had concentrations of 0.0459 mg/L and 0.0316 mg/L, respectively. Well MW8-CC had an iron level of 0.316 mg/L that exceeded the AL for this metal (0.3 mg/l). No other CSSA wells, including the remaining newly installed wells, exhibited metals levels that surpassed the MCLs/ALs during this monitoring event.
4.3 - Cations and Anions Analyses
Samples collected from thirteen newly installed CSSA monitoring wells during the June 2001 sampling event were analyzed for cations and anions. Further evaluation of the cation and anion data from all new monitoring wells, however, will be initiated as new wells are completed. A future groundwater monitoring report will include a detailed evaluation and data summary after sufficient data has been collected.
4.4 - Offsite Groundwater Monitoring
A sample was collected from private Well LS-7 during this sampling event and was analyzed for VOCs only. No contaminant levels above MCLs were found. PCE was detected at a concentration of 4.00 mg/L, which is a slight increase above the March 2001 level of 3.76 mg/L. Aside from the June 2000 results, where the PCE level dropped below its initial level, the presence of PCE has generally been increasing in Well LS-7 since sampling began over a year ago in December 1999. TCE was identified below the RL at 0.43 mg/L. The results of all sampling events for off-post wells are listed at the end of Tables 4 and 5 in the Introduction to the Quarterly Groundwater Monitoring Program at CSSA.