Recent Findings on the Extent of Contamination in the Lower Passaic River
Edward A. Garvey(1), AmyMarie Accardi-Dey, Juliana Atmadja, Susanne Biteman, Manali Desai, Adrian Ezeagu, Solomon Gbondo-Tugbawa, Cindy How, Shane McDonald, John Peake, Erika Zamek,
and Carolyn Zeiner
Malcolm Pirnie, Inc., 17-17 Route 208 North, Fair Lawn, NJ 07410, (201) 797-7400, (201) 797-4399, www.pirnie.com, (1) egarvey@pirnie.com
In support of the remedial investigation and feasibility study for the Lower Passaic River Restoration Project, Malcolm Pirnie, Inc. conducted an extensive geochemical evaluation of the historical data relating to contamination in the Lower Passaic River. In this evaluation, we examined the vertical and horizontal extent of contamination in the Lower Passaic River as well as evidence to identify contamination source areas. In addition to the use of historical geochemical data, we also evaluated historical bathymetric data and incorporated the results of a 15.5-mile side-scan sonar survey conducted in 2005. Our data sources included data obtained by Lamont-Doherty Earth Observatory, NJDOT, NOAA, Rensselaer Polytechnic Institute, Tierra Solutions, Inc., the USACE, and the USEPA. The geochemical evaluation represents a major step in the partner agencies’ investigation of the Lower Passaic River.
The geochemical evaluation addressed a broad range of issues including the following:
• Transport of contaminants and solids from the Lower Passaic River to Newark Bay.
• Vertical and horizontal extent of contamination in the sediments.
• Identification of historical and current (circa 1995) source areas to the Lower Passaic River, including the region above the Dundee Dam.
• The effects of transport processes on contaminants in the Lower Passaic River.
• Volume of contaminated sediments in the Lower Passaic River.
• Evidence for the possible identification of localized “hot spots.”
The evaluation led to a number of important conclusions regarding the Lower Passaic River. Among the more important was the lack of evidence to support the identification of “hot spot” areas where local remedial efforts could be focused. Rather, the evaluation identified the broad areas of contamination, on the scale of a mile or more in length and nearly the width of the river. Recent contaminant deposition was shown to be homogeneous throughout the lower 7 miles of the river, indicating that tidal mixing served to homogenize sediments over broad areas prior to deposition. While recently deposited sediments were homogeneous over long distances, deposition rates were not, with local variations of ±6 inches occurring over very short distances. Deposition rates were shown to be greatest in center of the river channel, atypical for an estuary but probably a direct result of historical channel dredging and recent lack of maintenance. Estimates of the volume of contaminated sediment in the Lower Passaic River (RM 0.9 to 7) ranged up to 8.0 million cubic yards with a corresponding average depth of contamination of 13 feet. Dated sediment cores were used to establish the depositional histories for a wide range of contaminants, including heavy metals, 2,3,7,8-TCDD, DDT, PCBs, and PAHs. Core data were also used to show that a number of contaminants, including mercury, PCBs, cadmium, and lead, have historically originated in the Upper Passaic River, above the Dundee Dam. Several contaminants, in particular mercury and PAHs extend below the depth of available core data, indicating that these contaminants have very old historical sources, probably extending to the early part of the 20th century. Forensic evidence for the 2,3,7,8-TCDD input to the Lower Passaic River as well as Newark Bay shows that the Lower Passaic River represents the dominant 2,3,7,8-TCDD input for the entire Newark Bay complex. Finally, estimates for the mass of 2,3,7,8-TCDD and mercury in the sediments of the Lower Passaic River (RM 0.9 to 7) were approximately
29 kg and 37 metric tons, respectively. The complete report can be found at http://ourpassaic.org/projectsites/premis_public/DM/Search/index.cfm/2006-03-06%20Draft%20Geochemical%20Evaluation%20(Step%202).pdf?fuseaction=GetDoc&DocId=5697