The NJDEP commented (October 2008)on the Draft Final Pre-Design Technical Memorandum for Group 1 Sites (PICA 079). Picatinny Arsenal provided their response to the NJDEP in an e-mail dated February 10, 2009.  Comments and responses are provided below.

NJDEP Comments:

“The preferred remedy for the TNT/RDX plume(s) is Monitored Natural Attenuation. The remedy is unacceptable, and violates N.J.A.C. 7:26E-6.1(b)3. The remedial timeframe of 11-13 years is based on the attenuation of contaminants to the Federal Drinking Water Health Advisories for TNT of 2.0 ug/l and RDX of 2.0ug/l. The New Jersey Ground Water Quality Criteria must be used. 

The preferred remedy for RDX is RDX-2 (Monitored Natural Attenuation), and is unacceptable. The criteria used to evaluate the contamination and remedy is unacceptable.

Page 10 describes the comparison criteria for RDX and TNT in groundwater as 2.0 ug/l. The remedial action fails to comply with state laws, regulations and requirements. 

The LOC for RDX in groundwater should be set to 0.5ug/l. This state criterion was set in place on September 11, 2006. The groundwater LOC for 2,4,6-TNT should be 1.0 ug/l. these are the New Jersey State Groundwater Criteria.”

Army Response:

“The U.S. Army and USEPA have agreed on a LOC of 2.0 ug/L for RDX and TNT per the Federal Drinking Water Advisory Level (HAL). This criterion is being used for RDX and TNT consistently across numerous USEPA Regions. However, per recent discussion pertaining to the RDX standard in the Mid Valley Feasibility Study, the U.S. Army has

 

 

developed text which acknowledges the States guidance number, and presents a remedial time frame to meet the NJDEP guidance number.  This information will be added to this Pre-Design Technical Memorandum, as well as other subsequent CERCLA documents, for informational purposes. Below is the text that will be added to the document.

‘In addition, regarding the TNT and RDX plumes, while the Health Advisory Level (HAL) of 2.0 ug/L is the selected criteria for RDX and TNT at Picatinny, the Army recognizes that the State of New Jersey has a non-promulgated guidance number of 0.3 ug/L for RDX (with a practical quantitation limit of 0.5 ug/L) and a non-promulgated guidance number of 1.0 ug/L for TNT. Anticipated remedy durations are calculated to achievement of the HAL, which will be the performance criteria of the CERCLA action. However, MNA durations to the NJDEP guidance numbers are also provided within this document for informational purposes’”               

The subject of cleanup criteria for RDX and TNT was apparently discussed again at the April 8, 2009 technical meeting and according to the meeting minutes they “...were discussed extensively.”  There was speculation that a final NJDEP decision would depend upon a decision being issued by a district attorney

 

general of the state attorney generals office. 

The NJDEP is concerned with the proposed use of the Federal Drinking Water Advisory Levels (HALs) instead of NJDEP’s interim guidance numbers for the contaminants. Despite the apparent lack of agreement with the NJDEP it has been reported  that Arcadis is moving forward with finalizing the Pre-Design Technical Memorandum.

Michael Glaab comments that “...the PAERAB is acutely aware of the need to assure that these water soluble contaminants are treated promptly enough to avoid offsite migration. The duration of a remedial action for a particular contaminant at a site should be  the amount of time required to remediate that site to an acceptable standard. But a significant disadvantage to relying on monitored natural attenuation (MNA) to remediate a site is the possibility that the site’s contaminants will migrate prior to being degraded. Arsenal groundwater does tend to slowly migrate beyond its borders to the south by southwest. The Rockaway River is nearby and Picatinny lies above large aquifers. Therefore time is a critical factor. Cleanup standards have to be sufficiently restrictive to be meaningful - and - the duration of MNA must be short enough to guarantee that the contaminants will decompose before they migrate elsewhere”.

 

Rdx AND TNT STANDARD IN PLAY AT PICA 079

Provided below for comparison purposes are the monitored natural attenuation (MNA) timeframe estimates to meet the

NJDEP Guidance Criteria: