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The Caldwell Trucking Co. site is located in Fairfield Township, New Jersey. It consists of properties and groundwater contaminated by the disposal of residential, commercial and industrial septic waste. Immediate actions to protect human health and the environment and soil cleanup have been completed.. Long-term groundwater cleanup is ongoing.

. Caldwell Trucking disposed of septic wastes in unlined lagoons on its 11-acre property from the early 1950s until 1973. After 1973, Caldwell installed underground storage tanks for the storage of these wastes. By 1984, the tanks were no longer used, and Caldwell operated solely as a transport facility until 1988, when it ceased operations. There are about 500 single family homes located in a populated area within one mile of the site. Since 1981, over 300 private wells in the area have been taken out of service due to contamination. The groundwater was found to be contaminated with volatile organic compounds (VOCs), including trichloroethene (TCE), tetrachloroethene (PCE) and 1,1,1-trichloroethane (TCA). The affected residences have been connected to the municipal drinking water supply system. The contaminated groundwater plume originating from the site flows north towards the Passaic River, which is used for recreational activities and as a source of drinking water. Parties responsible for the waste, called the Caldwell Trucking Site Trust, are cleaning-up the site and groundwater, with EPA overseeing the work.

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What Has Been Done to Clean Up the Site?

In the summer of 1989, EPA connected 55 homes and 9 commercial establishments in the contaminated groundwater plume area to the municipal water system. In May 1994, the PRPs installed a seven-foot high security fence around the entire site.

In September 1994, approximately 1650 yd3 (2640 tons) of lead and polychlorinated biphenyl contaminated material was excavated and disposed of off-site. Construction of the soil stabilization phase of the remedial action started in August 1995. However, in November 1995, the PRPs proposed to construct a soil vapor extraction (SVE) system due to high levels of odors and emissions during stabilization activities. EPA approved the request, and in June 1996, the PRPs started the SVE system. The PRPs operated the SVE system from June 1996 to March 1997, and removed over 25,000 pounds of VOCs (over 12 tons) from the soil. Stabilization of approximately 40,000 yd3 (64,000 tons) of contaminated soils was completed in September 1997. 

In October 1997, EPA was informed by the site owner of a new area of contamination. In September 1998, the PRPs stabilized an additional 1,000 cubic yards of lead-contaminated soils. In February 2001, the PRPs found additional lead-contaminated soils in the North Lagoon Area of the site. In July 2003, EPA approved the PRPs request to excavate and stabilize the remaining lead-contaminated soils and restore the wetlands in the area. Approximately 2,500 cubic yards of soil were excavated and stabilized from this area. The PRPs completed construction in early 2004, and EPA approved completion of the Soils Remedial Action Completion Report in September 2004.

During FY2005, the PRP's contractor completed a number of wetlands restoration tasks identified after initial wetlands restoration activities were completed. The wetlands mitigation was monitored twice a year for five years and they submitted Wetlands Mitigation Project Monitoring Reports annually beginning in January 2007. The Final Mitigation Project Monitoring Report, dated February 2011, included information on wetlands activities and data obtained during calendar year 2010. The information collected by Arcadis, the wetlands sub-contractor, indicated that the wetlands has continued to develop with increased wetlands diversity and continued planting and seeding work as well as additional spot herbicidal spraying to eliminate remaining invasive species. A November 09, 2010, letter submitted by NJDEP approved completion of the wetlands mitigation project.

In February 1997, EPA modified the groundwater remedial action schedule and allowed the PRPs to test the effectiveness of an innovative technology, an iron reactive wall system, to intercept the contaminated groundwater before it discharges at a surface water seep which flows into an unnamed tributary and into Deepavaal Brook. Monitoring results on the effectiveness of the iron wall indicate that the wall had reduced the VOC levels in the seep but not to acceptable levels.

In 2002, the PRPs completed installation of an air stripper treatment system to reduce the levels of contamination reaching the seep. The air stripper was upgraded in 2007 with a larger stripper, vapor phase carbon units for off-gas emissions and increased the pumping rate. The surface water influent, effluent and unnamed tributary are sampled monthly and the effluent consistently meets the NJPDES discharge requirements. However, groundwater contaminated with site-related contaminants is still reaching the unnamed tributary and Deepavaal Brook. To address this contamination, construction of an interceptor trench, French drains, a pump station, new discharge point and pipe cleanouts was completed in January 2014. Monthly samples of the new system’s effluent continues to meet the NJPDES discharge requirements. Downstream sample results, including new locations, will continue to be monitored by the PRPS and EPA to determine the effectiveness of the new treatment system. In December 2015, the PRPs submitted recommendations to improve the effectiveness of the new seep system and address a water ponding issue. EPA is reviewing the recommendations.

In October 2000, the PRPs requested permission to pilot test an enhanced biological treatment system in the VOC source area at the site. Results from the pilot test indicate that the system appears to be reducing the level of VOCs in the source area at the site. The PRPs requested permission from EPA to perform a Focused Feasibility Study (FFS) for the purpose of amending the current groundwater extraction and treatment system remedy. EPA and NJDEP notified the PRPs that the FFS was not approved and that they should begin implementing the original pump and treat remedy. The PRPs responded with a request to initiate informal dispute resolution. In November 2004, EPA and the PRPs agreed to hold the dispute resolution in abeyance while efforts were made to try and work out a compromise. The PRPs continue to inject accelerated in-situ biological (AISB) enhancements into several wells in the source area.

Construction and installation of the groundwater pump and treat facility, also known as the O'Connor Drive Groundwater Extraction and Treatment System (GERS) was completed in December 2008. Groundwater data is obtained from approximately 30 monitoring and piezometers wells on an annual basis and from 65 wells and piezometers on a biennial basis. Results from the groundwater monitoring are reported in Area-Wide Groundwater Evaluation Reports which include data from sampling of all active wells at the site included GERS wells and Groundwater Extraction and Treatment Annual reports which assesses the GERS system. The reports indicate that the system is operating as designed to contain the contaminated groundwater. The PRPs have conducted a pilot study to determine if groundwater effluent can be reinjected into on-site wells as opposed to the current disposal at the Two Bridges Sewerage Authority. EPA and the PRPs are currently in discussion over the 90% Design Report.

In 2005, high TCE contamination was found in well MW-33 in what is known as the North Lagoon Area (NLA). Between 2005 and 2014, the PRPs delineated the extent of highly elevated TCE levels in the NLA through a number of monitoring wells. In 2015, the PRPs proposed an AISB pilot study to address the contamination through a series of injection and monitoring wells. When the results of the study are submitted EPA will consider if this is a successful treatment approach for the NLA.

The PRPs submitted an Expanded Vapor Intrusion Work Plan in October 2006 and the PRPs began sampling residential and commercial properties downgradient of the Caldwell Trucking Site in April 2007. By August 2010, the PRPs have completed sampling with EPA oversight at nearly 100 residential properties included in the study area. Currently there are 18 properties where mitigation systems have been installed. The EPA reviewed data from the West Essex High School and two day care facilities in the vicinity of the Site indicate no further work is required for these sensitive populations. The PRPs continue to monitor residents with mitigation systems.

With the excavation and off-site disposal of contaminated material and stabilization of the remaining contaminated soil and waste materials at the site, all on-site soil contamination has now been removed or rendered harmless. The restored wetlands monitoring is complete after five years. The use of an alternate drinking water supply by affected homes and businesses in the area of the Caldwell Trucking Site has significantly reduced the potential for exposure to contaminated groundwater. However, high levels of groundwater contamination still remain, and the PRPs have completed the construction of a pump and treat containment facility to remediate the contaminated groundwater near the source area using extraction wells in the vicinity of O'Connor Drive. The upgrade of the seep area treatment system has been completed and additional investigations are being conducted.

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What Is the Current Site Status?

Site cleanup was addressed in three stages: immediate actions and two long-term remedial phases focused on cleanup of contaminated soils and groundwater. The immediate actions and the cleanup of the contaminated soils have been completed.
Immediate Actions: Several actions in 1990 reduced the potential for exposure to site contaminants. Chain-link gates and fences were put in place to restrict site access. The exposed lagoon and the four underground storage tanks were covered and surrounded with snow fencing. To minimize exposure of trespassing dirt bike riders to hazardous substances, parts of an access road were covered with geotextile fabric and stone. Warning signs were posted on the fences and at the entrance to the site.

Soils and Drinking Water: The remedy selected in the site’s September 1986 Record of Decision, or ROD, included: (1) restoring a lost drinking water resource by providing treatment of Municipal Water Supply Well No. 7; (2) providing an alternate water supply for residents potentially affected by groundwater contamination; and (3) digging up and treating about 28,000 cubic yards (yd3) of contaminated soils and waste materials via low temperature thermal treatment, and disposing of treated soils in a secure on-site landfill in accordance with Resource Conservation and Recovery Act (RCRA) requirements. In February 1995, EPA signed a ROD Amendment changing the 1986 ROD soil remedy to on-site stabilization/solidifications.

Groundwater: The remedy selected in the site’s September 1989 ROD required the installation of groundwater recovery wells at various locations throughout the study area to intercept the entire contaminated groundwater plume. The 1989 ROD also provided for a contingency remedy if EPA could not obtain community acceptance regarding access to the properties needed for implementation of the selected remedy. A 1993 Explanation of Significant Differences (ESD) changed the groundwater remedy to install groundwater wells to intercept the most contaminated portion of the groundwater. It also included cleanup of a seep that is recharged with contaminated groundwater.
The use of an alternate drinking water supply by affected homes and businesses near the site has significantly reduced the potential for exposure to contaminated groundwater. However, high levels of groundwater contamination remain. Site potential responsible parties, called the Caldwell Trucking Site Trust, have completed the construction of a pump-and-treat containment facility to remediate contaminated groundwater near the source area using extraction wells near O'Connor Drive. The Trust is now piloting biological treatment of groundwater, which has indicated success in breaking down contamination even further. The Trust has also treating a portion of the site where groundwater is emerging as surface water, called a seep, using air strippers and carbon filters.   Finally, the Trust has sampled nearby homes for vapor intrusion and installed mitigation systems as a precaution. All of this work has occurred with EPA's oversight.

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Activity and Use Limitations

At this site, activity and use limitations that EPA calls institutional controls are in place. Institutional controls play an important role in site remedies because they reduce exposure to contamination by limiting land or resource use. They also guide human behavior. For instance, zoning restrictions prevent land uses – such as residential uses – that are not consistent with the level of cleanup.

For more background, see Institutional Controls.

Chain-link gates and fences were put in place to restrict site access. To minimize exposure of trespassing dirt bike riders to hazardous substances, parts of an access road were covered with geotextile fabric and stone. Warning signs were posted on the fences and at the entrance to the site.

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Sampling and Monitoring

Over 95 wells have been installed in the area to monitor groundwater quality. The Trust provides montly sampling reports to EPA for the seep and groundwater pump and treat system. The Trust also provides an annual evaluation that reports and summarizes all data for the site and submits to EPA for review and approval.

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