Highlights of the FINAL PROPOSED PLAN  for Sites 61 and 104 (PICA 102)  -  continued 

discussed on page 12: 

“Groundwater contamination at both sites will be addressed separately under the Mid-Valley Groundwater Operable Unit. The RAOs are as follows:

· Manage soils with calculated risk in the risk range of 10^-6 to 10^-4  following NCP guidance and the Geis Memorandum;

· Maintain current land use (industrial) and current institutional controls;

· Control disturbance and exposure to site soils that could lead to unacceptable human health risks”.

The proposed plan further elaborates on page 12 about groundwater with the following statement:

“This Proposed Plan does not address groundwater at Sites 61 and 104 (PICA 102); therefore, COCs were not identified for groundwater at either site”.  

An underlying tenet influencing the Army’s selection of remedial actions at Picatinny Arsenal is the Geis Memorandum. This memorandum refers to an agreement concluded by the NJDEP and the U.S. Army. It is attributed to General Geis a former commandant of Picatinny Arsenal. The Geis Memorandum is alluded to in the following statement on page 2 :

“Per the Geis Memorandum, the Army agreed with NJDEP to control exposure to soils using technologies such as engineering controls and institutional controls rather than removal or treatment actions for sites where risks to human health fall within the generally acceptable risk range of 1 X 10^-4  to 1 X 10^-6.  Decisions regarding remedial actions at sites in this range are made on a site

 

 

 

by site basis under both the NCP and the Geis Memorandum. The excavation of AA_104SS-1  and AA_104SS-2  at Site 104 was considered appropriate based on contaminant concentrations and proximity to Green Pond Brook”.

According to the proposed plan an area of attainment (AA) is the area over which remedial action objectives are to be obtained. The determination of an AA is based on site cleanup level (SCL) exceedances. AAs were determined for both soil and sediment in Sites 61 and 104.  In Site 61 soil exceedances were identified at levels of 4 feet bgs. Therefore consideration was given to surface and subsurface  soil at Site 61.

The proposed plan provides the following human health summary on page 9 regarding soil :

“Unacceptable risks to human health and the environment under the current and reasonably anticipated future use were not identified in soil or sediments at Site 61 and 104 (PICA 102)”.

The plan clarifies its human health risk assessment on page 9 with the following human health summary regarding surface water and sediment :

“Human health risks were not quantified for exposures to surface water and sediments at either Site 61 or 104 as exposure to these media was not expected. However, concentrations of chemicals in surface water were compared to Region 3 Risk-Based Concentrations (RBCs) for tap water and New Jersey Water Quality Criteria. The maximum concentration of four chemicals exceeded a respective screening concentration based on drinking water exposure. However, because Green Pond Brook and Robinson Run are not used as a drinking water supply, exposure to surface water does not result in

 

 

an unacceptable risk to human health”.

The proposed plan elaborates further on page 12 regarding surface water contaminants :

“Six surface water contaminants (TCE, PCE, RDX, Aroclor 1016, Aroclor 1260, and lead) were initially determined to be a potential human health concern if surface water was used as a drinking water supply. However, as surface water is not used as a drinking water supply, these six contaminants are not considered a concern for human health, even taking into account potential incidental surface water ingestion. Swimming is prohibited within GPB, and swimming by a trespasser also is unlikely”.

The Army’s currently recommended response action as delineated on page 16   :

 “...would involve excavation of contaminated soil from AA_104SS-1 and AA_104SS-2 at Site 104, including confirmatory sampling at the limits of the excavation. Excavated soil would be transported off-site for disposal. Based on existing data, it is estimated that approximately 54 CY of contaminated soil would be excavated comprising an area of approximately 1,242 square feet. Sites 61 and 104 (PICA 102) would be subject to maintenance of existing ECs to prevent disturbance of the existing vegetative cover at AA_104SS-3 and exposure to contaminated soil.

Because some contamination above residential standards would remain at the site, LUCs will be required even after completing active remedies to control use of the site that may lead to unacceptable risk”.