Page 8 of the PAERAB's Spring 2011 Community Update Newsletter

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Close to ROD for Site 78? ( continued from p. 7)

Text Box: the Army specifically noted a concern that Mr. Putnam might not have actually seen and reviewed the most recent version of the document: “It is possible that Ed Putnam did not see the final ROD that has now been signed by the Army and is awaiting EPA’s Division Director’s signature. ...The last version ... was a tracked-changed WORD version ... supplied electronically on 7 March and quickly approved by EPA (Bill) the next day”. The Army elaborated further by asserting that changes to the ROD had been : “negotiated and modified since it was originally submitted to both the NJDEP and EPA almost a year ago; these changes were done mostly by emails and letters with the EPA with all correspondences copied to [the] NJDEP team.” The Army further stated that : “...we believe the answers should allow Mr. Putnam to sign a ‘concurrence letter’ to EPA and the Army for this ROD.” To be specific, Mr. Putnam offered the following comment regarding a concern that elevated laboratory detection levels might obscure lower concentration occurrences of certain constituents: ‘1. Figure 4: Elevated detection levels for VOCs in Surface water samples. DLs = 1 or 2 ug/l, when surface water ARAR /siite cleanup level is of 0.083 ug/l. ROD states that “surface water indicate that natural attenuation appears to be occurring at a rate that the contaminant mass is degrading prior to discharge at GPB”. How do we know if there’s VC in surface water

Text Box: or not, given these elevated DLs?’ The Army responded to above comment from Mr. Putnam in an e-mail sent by Mr. Ted Gabel on April 28, 2011 as follows: “The notations on Figure 4 (<2 U or <1 U) represent the laboratory reporting limit. Effective in 2010 regular quarterly sampling was initiated, at risk, consistent with the anticipated remedy of MNA. At this time results from 2 rounds of quarterly data are available and data for the third are pending. Trend plots for these data are attached to this email. The actual method detection limit utilized for the most recent sampling events (September and December 2010) is 0.250 ug/L. Although the NJ Surface Water Standard is lower, the laboratory defaults to the lowest achievable method detection limit. Also note that when detections occur below the laboratory reporting limit historically, they were reported and flagged as estimated (J). The data trend plots provided for SW-004 and SW-005 indicate VC was not reported at any of these locations and therefore the statement in the ROD is supported by the current data”. Mr. Putnam offered the following additional comment regarding detection levels: “2. Figure 3: Elevated detection levels of GW samples collected from stream piezometers at P- 78-PZ-002 and 003 * (Figure 2 shows detection levels of 10 and 20 ug/l ) Explanation is needed,” The Army responded in the referred to e-mail as follows: “The reporting limits for some constituents were elevated due to

Text Box: dilution. However, in the case of P-78-PZ-002 the most recent result did not have elevated reporting limits and no exceedances were present. In the case of P-78-PZ-003 a detection was reported and flagged for dilution (D)”. Mr. Putnam offered the following comment regarding the cessation of monitoring at several wells: “3. Figure 3: Groundwater sampling at 78-MW-006 and other wells was stopped in 2007 even though VC levels in the 006 had rebounded to close to the highest levels- not seen since 2004, Data from wells 78-MW-003, 004, 005 and especially 006 does not show a clear trend that contaminant levels will meet cleanup goals in 13 years. Why was the gw monitoring discontinued in 2007?” The Army responded as follows: “After the Pilot Study was completed in 2004, regular groundwater monitoring continued for two years and showed significant degradation. However, as expected, daughter compounds formed and, because of the nature of the degradation sequence, increasing levels of vinyl chloride were reported as the parent compounds degraded. These trends are shown by the attached trend plots. The 2007 data collection was conducted to assess the then current compound distribution although there was no regulatory requirement for sampling. These data indicated that indeed a temporal increase

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