7.0 Second Record of Decision (ROD): 1991
Record of Decision: September 26, 1991
Document: Located in Record of Decision Links
During the issuance of this second Record of Decision (ROD), the first ROD, signed in 1990, had resulted in a Remedial Action (RA) in September 1990. The RA was nearing completion during the signing of this second ROD on September 26, 1991.
Concurrent with the RA, a Focused Feasibility Study (FFS) and proposed plan were being prepared to address the remediation of the 34-acre slag area (OU-3) and the southeast park (OU-2). Principle threats were contaminated slag and soil containing elevated concentrations of heavy metals and polycyclic aromatic hydrocarbons.
7.1 Areas of Concern (OU-2) and (OU-3):
OU-2 Contained:
- Surface soil samples detected volatile and semi-volatile organic contaminants at low levels, except for PAHs in one sample.
- Chromium, lead, and zinc exceeded the State’s interim soil action levels and nearby background soil levels
OU-3 Contained:
Slag Area:
- 34 acres
- Ranging in thickness from several inches to 30 feet, thickest deposits were along the
Delaware River along the Site’s northwestern edge - Estimated volume of Slag material is approximately 1,458,000 cubic yards
- Material consists of very coarse soils, primarily comprised of residues from high temperature processing iron ore
- Slag fill contains numerous fissures and voids, allowing water infiltration
- Slag material contaminants included volatile and semi-volatile organic contaminants at low levels, except for acetone, 2-butanone, PAHs, and methylene chloride, which were above standard in the samples
- Inorganic contaminants were also detected at high levels, including, antimony, arsenic, barium, cadmium, chromium, copper, iron, lead, magnesium, manganese, mercury, nickel, selenium, silver, thallium, vanadium, and zinc.
- Detectable levels of lead in the leachate from two samples
- Estimated slag material needing treatment – 30,000 cubic yards
7.2 Human Health Risk Assessment/Environmental Risk Assessment:
Contaminants of concern for OU-2 and OU-3 were addressed separately. Heavy metals and polycyclic aromatic hydrocarbons were the most significant contaminants within the slag area, and to a lesser degree within the southeast park area. Lead was detected in the slag area at a maximum concentration level of 10,400 ppm (health based cleanup criteria in an industrial zone is 1,000ppm). Lead was detected in park soils at a maximum concentration of 261ppm (NJDEP Soil Cleanup Criteria in a residential area is 250ppm).
Exposure pathways for the public presented a potential risk for inadvertent ingestion and dermal contact with surface soil during recreational activities, as well as inhalation of suspended soils. During this time the Site was fenced off in order to restrict entrance to contaminated areas, signs of vandalism and trespassing were observed in these areas. Under the EPA guidelines the likelihood of carcinogenic and noncarcinogenic effects due to exposure of Site chemicals are obtained by adding the hazard quotients for all compounds across all media. A HI is determined, if the HI is greater than 1 it indicates a potential exists for noncarcinogenic effects to occur as a result of site-related exposure. The slag area, showed a noncarcinogenic HI of 27, therefore there was potential risk for noncarcinogenic adverse human health-effects, such as vital organ damage. For the southeast park area, the HI was less than 1, therefore the noncarcinogenic adverse health effects for this area is unlikely.
A baseline ecological risk assessment was conducted to assess the potential impacts to wildlife. Since both the slag area, and Southeast Park
7.3 Description of Alternatives:
Technologies eliminated included: incineration, superficial fluid extraction, biodegradation, washing and extraction, in-situ flushing, in-situ vitrification, in-situ solidification, stabilization of the entire slag area, off-site disposal. The reasoning for deleting these alternatives included incompatible treatment processes, and technical infeasibility.
Slag Area (OU-3) Remedial Alternatives:
Alternative SA-1: No Action
Estimated Cost: $31,600
Implementation Period: 2 Months
Annual inspection of monitoring equipment, as well as sampling and testing air and groundwater for 30 years.
Alternative SA-2: Limited Action
Estimated Cost: $72,100
Implementation Period: 4 Months
Maintaining a fence and warning sign along the slag area, long-term monitoring program, and public awareness. 30 years of monitoring, institutional controls on land and groundwater use would also be implemented under this alternative, and would include a deed restriction and groundwater use restriction.
Alternative SA-3: Treatment of Hot-spots and Soil Cover
Estimated Cost: $6,758,900
Implementation Period: 1 Year
Construction of a soil cover over the slag area to contain the contaminated slag material, the cap would be sloped to allow precipitation to flow easily into a drainage system that would runoff into the river, restrict runoff coming from adjacent areas, and minimize erosion. Cap would consist of a 2 foot deep, vegetated top soil layer that would extend to the side slopes. Riprap would be provided along the river shoreline to minimize erosion. Long-term groundwater monitoring and a 5 year review. Areas leaching contaminants would be excavated and treated on-site using a mobile treatment unit. A treatability study would be performed during the remedial design process. If contaminated material (slag that fails TCLP test) is found below water table, dewatering may be necessary during its excavation. Extracted water would be collected, treated, and disposed. The treated slag would be returned to an area above the water table to prevent placement in a wet location, which could affect the stabilized slag. Solidified slag would have to pass the TCLP test before it could be redeposited on site.
Alternative SA-4: Multimedia RCRA Cap
Estimated Cost: $11,597,700
Implementation Period: 1 Year
Capping requirement set forth by Federal and State Law. A small portion of slag area that is in the 100-year flood plain area would be graded above the flood plain. Multi-layer RCRA cap would be installed over entire area. The cap would be sloped to allow precipitation to flow easily into a drainage system that would runoff into the river, restrict runoff coming from adjacent areas, and minimize erosion. Cap would consist of: 2 foot clay layer with a permeability less than 10 centimeters per second, 20 millimeters high density polyethylene membrane, 12 inch sand layer for drainage, geotextile filter fabric layer, and 2 foot deep vegetative top soil layer. Riprap would be provided along the river shoreline to minimize erosion.
Alternative PS-1: No Further Action
Estimated Cost: $0
Implementation Period: 2 Months
No action alternative consists of a long-term monitoring program to assess the migration of park soil contaminants. This action would involve soil sampling for 30 years. A review would be completed after 5 years, determining whether the remedy was still protective.
Alternative PS-2: Limited Action
Estimated Cost: $59,500
Implementation Period: 4 Months
No active remediation. Installing fence and warning signs. Public awareness program. Monitoring program would continue for 30 years.
Alternative PS-3: Excavation and off-site Disposal of Contaminated Soil
Estimated Cost: $114,500
Implementation Period: 1 Year
Contaminated soil excavated and transported off-site. Estimated volume based on soil exceedances. Excavated area backfilled with clean soil and re-vegetated. Additionally soil sampling would be performed during design phase to confirm extent of contamination.
7.4 Selected Remedy:
The selected remedy for the slag area was SA-3, this alternative was selected for its ability of treat highly contaminated areas and contains the entirety of the slag area with a soil cover. The alternative provided a high level of protection by reducing risks associated with exposure to slag contaminants and reducing migration to the environment. The alternative for the southeast park was PS-3, this alternative was selected for its ability to remove contaminated park soil to an off-site facility and remediate contaminated soil, eliminating potential risks of exposure.
7.5 Completion:
Operable Unit 2 (OU-2):
The remedy selected for the Southeast playground (OU-2), which included excavating contaminated soil hotspots, off-site treatment of contaminated soils, and disposal at the appropriate facility, was conducted by the Region II Removal Action Branch of the EPA. The COE submitted the final design to the EPA, in the Fall of 1994. Remedial Action was completed in March 1995. Approximately 640 cubic yards of contaminated park soil was excavated and restored with clean soil and vegetation. Since all contamination associated with OU-2 ROD was removed, a five-year review is not required for this remedy.
Operable Unit 3 (OU-3):
The remedy selected for the Slag Area, which included treating hotspots (defined as highly contaminated slag material that fails the RCRA Toxic Compound Leaching Procedure test), and then covering the entire 34-acre slag area with a soil cover and vegetation, was amended in 2003, the original remedy selected for the OU-3 was modified.
Design and construction activities are ongoing for OU-3. Design and construction activities for the shoreline stabilization component were completed in July 2006 and November 2006. These included grading shoreline slopes, placement of geotextile fabric and placement of riprap rock to construct the revetment. Installation of 3,000 linear feet of shoreline revetment stabilized the Slag area and better prepared the Slag area to receive the dredged sediments in November 2006. The Slag area is currently receiving dredged sediments.
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