Page 1 of the PAERAB's Summer 2009 TAPP Contractor Newsletter

Text Box: A draft final work plan for additional investigation related to the Mid-Valley Groundwater Feasibility Study (FS) was one of the topics of discussion at the recent September 17th technical meeting convened by Arcadis for Picatinny Arsenal, the Army Corps of Engineers, the USEPA, and the NJDEP representatives. Groundwater contaminants in Mid-Valley groundwater include trichloroethene (TCE), tetrachloroethene (PCE), and explosive cyclonite (RDX). The purpose of this work plan is to test a revised conceptual site model (CSM) proposed by Arcadis. Pre-design investigation by Arcadis in the spring of 2009 revealed potential discrepancies with the existing CSM. Basically the CSM put forth by Shaw Engineering (the firm that had worked on the IRP [Installation Restoration Program] prior to award of the performance-based contract to Arcadis) centered on the existence of a buried bedrock channel or valley filled with sediment. This channel was supposed to be coincident with the southern portion of the TCE plume. Shaw had confirmed that this glacial fluvial valley rests on bedrock with multiple well borings. Arcadis installed two extra monitoring wells at the site in April of 2009. As a result Arcadis’ data suggests the presence of weathered bedrock in the

POINTS OF INTEREST:

· The next RAB meeting is scheduled for Thursday, October 29^nd at the Hilton Garden Inn in Rockaway, NJ. The RAB meeting will commence at 7:30 pm after a public meeting. As with all RAB meetings members of the public are invited to attend.

· A public meeting will also be held at 6 pm on Thursday, October 29^nd at the Hilton Garden Inn in Rockaway, NJ. Its purpose is to provide a hearing for the Proposed Plan for Group 3 Sites. Members of the public are invited to attend.

· The most recent Arcadis technical meeting was held on September 17, 2009.

· The next Arcadis technical meeting is scheduled for November 12, 2009.

Area C / NJ Standards	2
600 Area Comments	3
Off-site disposal	4
soil cover depth	4
training	4
Pica 001	5
Bog turtle blight	5
DRMO YARD MEC	6
Monitoring / oswer	7
Land use / mid-valley	9
Pica 001 luc	10
Cleanup template	11
Group 3 sites	13

Summer 2009

Volume 8, issue 3

Text Box: Environmental Happenings At Picatinny Arsenal

Text Box: Recent field activities for June through September 2009 included the following: Former DRMO Yard: Soil sampling (June, August); Clearing of excavation areas (July and August); excavation

Text Box: and demolition (July and August); excavation backfilling (August); and installation of soil consolidation cover (September). Area D – Golf Course: Measurement of water levels, installation of passive diffusion

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MORE INVESTIGATION FOR MID-VALLEY

Text Box: Editorial Reviewers David Forti, Michael Glaab ———————- Technical Advisors Ted Gabel, William Roach, Gregory Zalaskus

bags (PDBs) and groundwater

$Text Box: interval that had previously been classified as “channel fill” (sand, gravel, and cobbles). Further examination of drilling logs by Arcadis showed that previous investigators had relied on drill cuttings to determine the nature of the subsurface material rather than relying on the analysis of split-spoon samples and/or core samples. In addition, the exact location of the supposed “buried bedrock channel” has been called into question. For example, one of Shaw’s figures depicts the “approximate footprint of the bedrock channel” as being directly north of Robinson Run while in discussions between Arcadis and Shaw representatives, Shaw had suggested that the “channel” may actually be slightly south of Robinson Run. Another seeming discrepancy with the CSM was identified when groundwater sampling results were received for the two new monitoring wells. Sampling results disclosed that concentrations of TCE were different from what would have been predicted according to the CSM. It is possible that the southern TCE plume is not continuous. Geophysical survey information derived from a seismic refraction study performed in 2003 by Shaw shows three discrete layers in the study area. Layer 1 was identified as consisting of unconsolidated to$

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