U.S. EPA Contaminated Site Cleanup Information (CLU-IN)


U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Fractured Bedrock Project Profiles

Last Updated: January 1, 2011

Point of Contact:
Sameh Abdellatif
USEPA
290 Broadway
New York NY 10007-1866 
Tel: 212-637-4103 
Email: abdellatif.sameh@
pa.gov

Former Inmont Corporation Hawthorne Plant
Hawthorne, NJ


Hydrogeology:

The site is physiographically located in the Piedmont Province of north-central New Jersey. It is locally situated in a broad valley bordered to the west-northwest by the Watchung Mountains (Orange Mountain Basalt) and to the south by the Passaic River. In general, the bedrock beneath the site is overlain by unconsolidated glacial deposits (overburden). The overburden is primarily composed of glacial-fluvial and glacial-lacustrine deposits consisting of moderately sorted silt, sand, and gravel layers, which range in total thickness from 30 to 50 feet. Bedrock beneath the site is comprised of the Passaic Formation, which
generally consists of interbedded red sandstone, siltstone, shale, and conglomerate.

The groundwater system beneath the site consists of two aquifers: an overburden aquifer and a bedrock aquifer. The bedrock aquifer is further segregated into an upper bedrock unit and a lower bedrock unit. The overburden aquifer is typically unconfined and groundwater flow is controlled by topography. Some
of the well-sorted, coarser-grained glacial deposits are capable of yielding large quantities of water.
These deposits are generally limited to the south-southeastern portion of the site. Under non-pumping conditions, groundwater flow in the overburden aquifer beneath the site is to the south, towards the Passaic River, which acts as a discharge area. Depth to the
overburden aquifer ranges from approximately six feet to 50 feet bgs.
Groundwater within the bedrock aquifer is contained primarily within secondary porosity features and is sometimes found under artesian conditions. Regional groundwater flow within this aquifer is strongly controlled by the structural features within the formation. Outcrops in the vicinity of the site indicate that near vertical fractures tending northeast to southwest are the primary pathway for groundwater movement. However, the interbedding of the formation also displays fractures (cleavage and parting) that can store and allow the migration of groundwater in a direction roughly perpendicular to the strikes
and the near-vertical fractures. The upper bedrock aquifer is found at a depth up to 90 feet bgs, while the
lower bedrock unit is found at depths of greater than 90 feet to approximately 250 feet bgs. Under non-pumping conditions, groundwater in the upper portion of the bedrock aquifer flows south and likely discharges to the Passaic River. Groundwater flow direction in the lower bedrock is to the north/northwest
toward the municipal well field and also to the south towards the Passaic River. A groundwater divide is apparent across the center of the site.

Targeted Environmental Media:
  • - Dense Non-aqueous Phase Liquids (DNAPLs)
  • - Fractured Bedrock

Contaminants:

The vertical depth of the plume is to at least 250 feet bgs. The lateral extent was not given.

Major Contaminants and Maximum Concentrations:
  • - Benzene (24 µg/L)
  • - Styrene (151 µg/L)
  • - Nitrobenzene (4,930 µg/L)
  • - 1,2,4-Trichlorobenzene (194 µg/L)
  • - 1,4-Dichlorobenzene (82 µg/L)

Site Characterization Technologies:

No technologies selected.


Remedial Technologies:

  • - Pump and Treat
Comments:
Contaminant levels above are for the upper bedrock and date from 2003. The lower bedrock has a nitrobenzene maximum concentration of 218,000 ug/L.
Remediation Goals:

New Jersey Groundwater Quality Standards.


Status:

The pump and treat system for the overburden and upper bedrock aquifer consists of three overburden wells and five upper bedrock wells. This system has established containment of the plume. The company will complete a report on conditions in the deep aquifer in late 2009.

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For more information on Fractured Bedrock, please contact:

Ed Gilbert
Technology Assessment Branch

PH: (703) 603-8883 | Email: gilbert.edward@epa.gov