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The City of Trenton, New Jersey, has used the Triad approach to successfully advance the plan to convert 60 acres and 11 parcels of land along Assunpink Creek to recreational use. Among the parcels were a wire manufacturer, rail yards, and auto repair shops. This profile focuses on the wire manufacturer, Crescent Wire, Inc.
Following a brief initial field test of analytical methods (Phase I), the main, Triad-based field program (Phase II) was accomplished in four days at the 3-acre Crescent Wire property. The Triad program used a dynamic data collection approach, guided in the field by decision logic, to assess nature and extent of contamination in soil and groundwater, answering the principal study question of a possible connection between contaminants of concern (COCs) at the site and those found in the adjacent Assunpink Creek sediments. The amount of data collected was sufficiently representative to allow agreement among the stakeholders that the COCs found at the Site were actually from upgradient sources. The data further allowed the stakeholder team to agree upon the need and design of a long-term monitoring system and remedial approach for the area.
| Site Name | Assunpink Creek Greenway Project - Crescent Wire |
| Location | Trenton, NJ |
| Site Type |
Cable and Wire Manufacturer |
| Project Lead Organization | City of Trenton entered into a Memorandum of Agreement with New Jersey Department of Environmental Protection (NJDEP) |
| Project Lead Type |
Municipal/Local Lead |
| Regulatory Lead Program |
Voluntary Cleanup Program |
| Triad Project Status | Field Program Completed |
| Reuse Objective Identified |
Yes |
| Proposed Reuse: |
Recreational |
The Crescent Wire site is currently owned by the City of Trenton and was formerly used for the manufacturing of high-tension cables and wires. Operations ceased pre-1995 and the building was destroyed by fire in 1996. Currently, the site is primarily covered by concrete, and is used as a parking lot for a nearby business. The reuse strategy for the Site is conversion into a greenway along Assunpink Creek with walking and biking trails.
After a brief initial Phase I program that verified the appropriateness of the investigation methods, identified potential areas of concern (AOCs), and assessed the presence of fill across the Assunpink Greenway study area, the dynamic investigation of the Crescent Wire site (Phase II) was completed in four days. The field-based analytical methods verified in Phase I (test kits and x-ray fluorescence [XRF]) were used in conjunction with fixed off-site laboratory analysis and field observations to delineate the COCs at the Site. The findings verified that the predominant COC was TPH in oil-saturated soil located at or just below the water table, with low levels of PCBs. The investigation revealed that these COCs were related to upgradient sources rather than activities at the Crescent Wire property itself. These COCs were found in soil at concentrations above NJDEP residential standards, which were established by the stakeholders as cleanup criteria for the greenway parcels. In addition, metals were found above standards in historic fill material. Readers are referred to the Points of Contact (POCs) listed below and the Site and Remedial Investigation Report for more information.
Because the area along Assunpink Creek has been industrialized since the late 1800's, the extent of contamination was largely unknown as redevelopment began. Preliminary assessment indicated potential presence of heavy metals, petroleum hydrocarbons, PAHs, and PCBs. A dynamic approach was used to investigate an area with oil staining and PCB impacts at the water table. The objectives of the dynamic investigation were as follows:
The Triad approach successfully investigated the environmental characteristics of the Crescent Wire site in a shorter timeframe and with greater detail and certainty than would have been possible with traditional methods. The key was the emphasis on systematic planning that resulted in the proper use of a range of field analytical instruments to allow on-site decision-making.
A quantitative evaluation of cost savings was not performed by the project team or stakeholders. However, the Triad approach allowed for the combined site investigation (SI) and remedial investigation (RI) activities (including plan and report preparation) to be compressed into less than a three-month period. Schedule-wise, the project team estimated a time savings of six months to a year. The total costs of the field investigation, including off-site confirmatory analytical samples was $32,727. This investigation was completed over four days.
The success of the brief field program in characterizing the Site without the need for additional mobilizations may have produced significant cost- as well as time-savings over a traditional "phased" approach. Moreover, using lower cost field-based methods allowed for the collection of more samples during the field investigation, which reduced the uncertainty of site characterization.
The systematic planning process involved a careful review of existing environmental data from the site, the generation of a conceptual site model (CSM), and several meetings with stakeholders to identify project objectives and reach a consensus on an investigative approach that involved two phases. The CSM was developed based on the findings of Phase I.
A dynamic work plan was developed for the Phase II investigation of select AOCs, as appropriate, identified in Phase I. These AOCs including the PCB/oil impacts at the Crescent Wire site as well as several AOCs in the Rail Yard Site. The dynamic work plan included multiple features designed to promote real-time decision-making in the field, such as:
The principal decision-making party for the Site was the City of Trenton, working in cooperation with NJDEP. The project management team and field team were from Langan Engineering and Environmental Services (Langan) and S2C2, Inc., contractors for the City of Trenton. Langan provided a full complement of project support staff for the project, including geologists, hydrogeologists, and engineers. S2C2, Inc. provided on-site chemists, drilling, and analytical services.
The City and NJDEP called for a dynamic work strategy (DWS) in the request for proposal (RFP) to hire the technical support contractor for the field investigation. The project team found that the DWS and the Phase I results presented in the RFP greatly improved the quality and creativity of the bid packages and produced focused yet flexible pricing schemes. The selected contractors (Langan and S2C2) finalized the DWS and prepared the dynamic work plan with input from all stakeholders, including the City of Trenton, the USEPA, and the NJDEP. Upon mobilization to the field, the DWS relied on an analytical program of collaborative methods to achieve high sample densities while still attaining low detection limits for specific COCs at decision points. Sample results from these methods were integrated on a continual basis to support daily field decisions.
The DWS framework allowed for shifts in decision logic to address new study questions and data gaps as they arose during the field investigations. A recent journal article shows the sampling approach that evolved dynamically for the Crescent Wire investigation.
At the Crescent Wire site, initial samples were located to delineate a potential hot spot for PCBs and TPH found during Phase I. However, when real-time results implied a wide-spread area of contamination, the decision logic shifted from hot spot delineation to assessing the width and source of the plume. Sampling along the upgradient property for similar COCs and samples collected continued along the boundary until the edges of the plume were identified. Having now substantially improved the CSM by determining that the plume was originating from an upgradient source and was confined to a thin layer of floating weathered product, the decision logic called for a determination of whether the contaminant in the plume had impacted creek sediments downgradient of the Crescent Wire property. This final phase of the DWS established a pattern of borings marching downgradient along the eastern edge of the site, immediately upgradient of Assunpink Creek. The borings rapidly mapped the extent of the PCB/TPH smear zone and established that there were downgradient discharges to the creek from the site or the upgradient source. Overall, the DWS quickly resolved the primary decision questions regarding extent of contamination at the Crescent Wire property with a single mobilization.
More details concerning the decision logic are presented in the Dynamic Work Plan (PDF, 13 MB) and a recent journal article (See reference below).
Direct-push methods were used to collect samples. Selected samples were split between the mobile lab and the DEP-certified fixed lab as a check on the field-based method results. Several split samples were collected from the assessed boundaries of the TPH/PCB impacted area to confirm the delineation achieved by field-based methods and to satisfy NJDEP's requirements for certified data. Two spilt samples were collected for off-site analysis in the area of highest concentrations to check the precision of the field-based method results.
Phase I included a demonstration of method applicability (DMA) to verify the utility of the proposed field-based methods and assist in the design of the Phase II investigation. The DMA assessed direct-push methods, downhole conductivity probes, XRF methods for metals, and test kits and for TPH and PCBs.
TQRS not available
Split samples were used to develop comparison data sets using the mobile laboratory and a NJDEP certified laboratory. The comparison indicates that if the mobile laboratory data indicated a sample was below the NJDEP standard, its split sample sent to the fixed laboratory also was typically below the standard. The mobile laboratory data tended to be biased high when compared to the fixed laboratory data.
The laboratory provided the analytical data daily to the field team leader from Langan. This data was immediately compared to NJDEP standards and mapped on-site maps. The sample results were used to plan the next sampling locations according to the decision rules in the Dynamic Workplan. The field team leader communicated the data to a Langan Project Manager daily and discussed the next sampling locations. The Langan Project Manager provided status updates to the NJDEP and the City of Trenton. Prior to each sampling day, the field sampling crew discussed the previous results and the next sampling locations.
Crescent Wire field work conducted in January 2003.
Phase II field work for all Assunpink greenway projects was completed in less than one month in early 2003.
609-989-4238
leah@njbrownfield.com 973-596-5857 mack@adm.njit.edu 215-348-7101 nderose@langan.comTo update this profile, contact Cheryl T. Johnson at Johnson.Cheryl@epa.gov or (703) 603-9045.
