Sites on the shore of picatinny lake

proposing ideas and plans that are later formulated into documents which are then submitted to regulators for their review. This memorandum

includes the Army’s recommendation of “GW-2 – Continued Implementation of Institutional Controls and Monitored Natural Attenuation (MNA) as the preferred Response Action for groundwater.” 

The memorandum cites Arcadis contention that the concentrations of TNT and RDX are decreasing and that there is evidence to support continued MNA. As is required by the USEPA for MNA alternatives, the memorandum  calculates time frames for the dissipation of those contaminants. The USEPA was quick to respond  on November 6, 2008 by noting that it did not find a decreasing trend in concentrations of TNT and RDX. The USEPA also pointedly questioned whether or not the plume was in fact actually migrating elsewhere rather

than just attenuating naturally. Or is the plume perhaps migrating and attenuating?  Plume maps contained in the report (Figures 3 and 4) are interesting. However, the depiction of RDX plumes in 2002 versus 2008 (Figure 4) seems to indicate that the areal extent of higher RDX concentration (greater than 10 ug/L) has actually expanded rather than contracted as one would expect in a situation of attenuation. An expansion implies – but does not guarantee — that RDX migration may be occurring.  No statistical analyses

 were included in the document to support the contention of a trend of decreasing RDX concentrations. The Army/Arcadis has not yet responded to the USEPA’s query. The Army’s response to the USEPA will be provided in a newsletter as and when it becomes available. However, Arcadis has provided the following explanation of its perspective:

“…We believe there is no disagreement between the

PHASE-IN  GUIDANCE  FOR  NEW  SOIL  STANDARDS

New Jersey’s recently enacted soil standards have had an effect on some of the sites at Picatinny Arsenal that are in the process of being  remediated. Arcadis has determined that the Record of Decision (ROD) and Remedial Design (RD) for Area B (PICA 205) are not subject to

the phase-in period for the new NJDEP soil standards. In

consultation with the NJDEP, Arcadis determined that Sites 61 and 104 (PICA 102) and Sites 31 and 101 (PICA 72) can proceed under the phase-in guidance. The RAB’s DoD Co-chmn., Mr. Ted Gabel,

comments : “...older Soil Cleanup Standards are more stringent for certain parameters than those recently promulgated by NJDEP. This particularly is relevant to lead removal aspects at Site 31/101”.

Pending documents for the two sites are expected to be updated with language acknowledging the recent promulgation of new standards but these documents will not identify the new soil standards as ARARs.

EPA and the Army regarding the migration of RDX and TNT at PICA 079. In fact, it was noted during its presentation of the data to the EPA and DEP that migration of the contaminant and discharge into the Lake was likely occurring, as well as attenuation by chemical breakdown. All parties agreed on this data trend, and all parties agreed that sampling of the lake sediments and water at the points of groundwater discharge was important. This work was completed by Arcadis on an expedited basis and no detections of explosive were reported in either media. The referenced 6 November 2008 EPA memo was an approval of the document”.   

Michael Glaab comments : “...the possibility that the migration of a contaminant will occur undetected and that its migration will be misinterpreted as evidence of attenuation is a risk in and of itself. This risk will tend to be larger for water soluble contaminants and it will probably be directly proportional to the ease with which those contaminants go into solution in water.”