Metropolitan Transportation Authority Long Island Rail Road Voluntary Cleanup Agreement
Posted on June 22, 2015
Client: Metropolitan Transportation Authority Long Island Rail Road
Location: Suffolk, Nassau and Queens Counties, New York
Project Type: Investigation and Remediation of 20 Substations for PCB and Mercury Contamination
The Long Island Rail Road (LIRR) entered into three Voluntary Cleanup Agreements (VCAs) with the New York State Department of Environmental Conservation (NYSDEC) to perform investigations and remedial actions at 20 LIRR electrical substations found to contain mercury and polychlorinated biphenyl (PCB) contamination. The LIRR retained the services of D&B Engineers and Architects, P.C. to perform this work.
The LIRR constructed, operated and maintained substations from the early 1930s through 1951 that utilized mercury rectifiers and transformers which contained PCBs. The rectifiers allowed the LIRR to receive 60-cycle, alternating current (AC) from local utilities and convert it to direct current (DC) for use as a source of electric power for its locomotives and electric passenger car fleet. It is believed that during the early 1980s, the remaining mercury rectifiers were taken out of service and physically removed from these LIRR substations and replaced with nonmercury-containing solid state equipment. However, due to uncertainties surrounding the work practices that may have been employed when managing the operation and maintenance of these mercury rectifiers, the LIRR believed it was necessary to conduct environmental assessments to determine the potential effects that may have occurred to the surrounding environment.
The 20 substations are located throughout Suffolk (2 sites), Nassau (13 sites) and Queens Counties (5 sites) on Long Island, New York. As part of that program, D&B identified mercury and PCB contaminated soil at all 20 substations. Due to impending LIRR substation upgrade requirements associated with the upgrading of the rail system to accommodate the new fleet of M7 train cars, additional investigation and remediation of these three substations was given priority over the remaining 17 substations that were initially investigated.
Investigation Scope of Work
After completing initial investigations of all 20 substations in 1999, D&B undertook more comprehensive investigations, starting in 2002 with the Massapequa, Island Park and Manhasset Substations and the investigation of the remaining 17 substations in 2005. The primary objective of the site investigations were to further delineate the extent of impacted soil within areas where mercury had previously been identified during the initial Site Assessment of the 20 substations conducted in 1999. The Scope of Work associated with this project was conducted simultaneously with two other environmental projects which D&B was undertaking at the substations, namely an Underground Injection Control (UIC) Closure program and Construction Excavation Sampling and oversight. As a result, continuous cooperation between the LIRR’s System Safety, Substations, Flagging and Capital Departments, as well as the Nassau County Department of Health, NYSDEC, subcontractors, and local residents and business owners was paramount. The ongoing field investigation of the 20 substations will include:
Human Health Exposure Assessment
- collection of approximately 1,000 surface soil samples for chemical analysis;
- collection of approximately 2,000 subsurface soil samples for chemical analysis;
- advancement of approximately 1,200 soil probes both outside and inside the substations structures;
- installation and sampling of an 86-foot monitoring well at the Manhasset Substation;
- advancement and sampling of 56 groundwater probes;
- collection of four sediment samples within Manhasset Bay;
- continuous air monitoring of the breathing zone for mercury during sampling activities; and
- Fish and Wildlife Resources Impact Analysis at eight of the Substations.
As part of the second phase of the investigation, referred to as the Delineation Phase II Site Assessments, D&B has completed an exposure assessment at each Substation to determine how and when an individual might be exposed to contaminants of potential concern under existing and future site conditions.
The objectives of the Human Health Exposure Assessment for the three substations include:
- provide a determination of potential risk under current/ baseline site conditions, including identification of contaminant migration pathways and potential receptors;
- provide a basis for determining contaminant levels that provide adequate protection of human health and the environment;
- assess exposure pathways associated with surface soil, subsurface soil, groundwater and air; and
- identify the need for corrective measures.
Interim Remedial Measure Program
The initial field investigation program completed in 1999 clearly indicated that certain substations exhibited mercury and/or PCB-impacted soil either within or immediately adjacent to the facility. In certain situations, it was concluded that the presence of mercury and PCBs could pose a potential human exposure scenario. This was primarily due to the potential impact to on-site substation operation and maintenance personnel as well as the proximity of certain impacted areas to train platforms, access to train platforms and other areas that could be traversed by the general public. As a result, the firm was requested by the LIRR to develop a Statement of Work that would allow the railroad to retain a remedial contractor to undertake and complete a series of Interim Remedial Measures (IRMs).
The IRM program was implemented at electric substations that exhibited an immediate exposure pathway for on-site workers or pedestrians. The program basically consisted of the excavation and removal of mercury-contaminated soil in areas immediately adjacent to each of 11 electric substations identified as having a potential exposure scenario. Subsequent to the excavation and removal action, endpoint soil samples were collected by the firm to demonstrate the effectiveness of each IRM and to determine if additional delineation sampling and analysis would be needed during the next phase of work. The firm also provided engineering oversight of the IRM program to ensure the implementation of all activities associated with the removal program and document its successful completion. Each of the areas excavated was backfilled with clean soil and “blue stone.”
Remedial Action Work Plan
Based on the results of the investigation described above, D&B has completed a Remedial Action Work Plans (RAWPs) for each substation that included the evaluation of several remedial alternatives to eliminate or mitigate identified potential exposure pathways at the various substations. Remedial alternatives for each substation were selected based on this evaluation and the RAWPs included a detailed description of the selected remedial alternative.
Upon approval of the RAWPs by the NYSDEC, D&B will proceed with the full scale design of the selected remedial alternative for each of the remaining substations.
As of the winter of 2013, D&B has completed remedial activities at 11 of the 20 substations. These remedial activities have included:
Underground Injection Control (UIC) Closure Program
As discussed above, D&B conducted a UIC closure programs at the several substations. This program consisted of the following activities:
- drainage/discharge determination to identify the discharge points of various floor drains, slop sinks and pits inside and outside of the substations;
- subsurface soil sampling to depths ranging up to 20 feet bgs at 20 structures;
- engineering oversight of soil excavation from the bottom of 18 UIC structures, including the demolition and removal of a 10-foot deep dry well within saturated soil in Island Park and excavations in level C (respirator) protective equipment beneath concrete pits inside the Manhasset Substation;
- post-excavation endpoint sampling to confirm successful remediation; and
- engineering oversight of backfilling and concrete capping of injection well.
Through continuous coordination with the LIRR, NCDOH and USEPA, D&B successfully closed 20 UIC structures at eight substation sites.
Construction Excavation Sampling Program
As discussed above, the LIRR was in the process of performing substation upgrades at the substations in order to accommodate their new fleet of M7 train cars. These upgrades called for the replacement of the rectifier and transformer equipment. In addition, the LIRR had plans for erecting an entirely new substation adjacent to the existing Island Park Substation and prior to demolition and construction, D&B conducted subsurface soil sampling to identify any site-related impacts within areas that had been planned for excavation.
As part of the Construction Excavation Sampling Program, D&B advanced a total of 31 soil probes at the three substation sites to depths of up to 20 feet below grade. Sample analysis included Target Analyte List (TAL) metals, Semivolatile Organic Compounds (SVOCs) and PCBs. The results of this sampling program indicated isolated areas where these constituents were found to be in excess of the NYSDEC Technical and Administrative Guidance Memorandum (TAGM) 4046 Recommended Cleanup Objectives. However, these constituents were not detected at levels which would invariably pose a threat to the health of on-site construction personnel or LIRR employees.
Construction Excavation Engineering Oversight
Subsequent to the Construction Excavation Sampling Program, the LIRR utilized an environmental remediation contractor to conduct the excavations of all areas necessary to support the substation upgrades. In association with this effort, D&B provided engineering oversight to ensure that all appropriate areas were excavated to the required depths. In addition, D&B implemented a health and safety plan, which included community air monitoring, to ensure the safety of all on-site personnel. Throughout this project, D&B acted as a liaison between the LIRR and their remedial contractor, often coordinating various logistics associated with a successful outcome. Some of these issues included the following:
- daily and weekly scheduling of remediation to allow the LIRR as much commuter parking as practical (Island Park Substation);
- enforcement of work plan requirements to prevent LIRR nuisances to local residences (Manhasset and Island Park); and
- assistance in daily coordination between LIRR System Safety Department’s remedial contractor and LIRR Capital Department’s civil contractor (Island Park).
For more information about this service, email us at firstname.lastname@example.org.