Superfund Information Systems: Site Profile

Superfund Site:

PINE STREET CANAL
BURLINGTON, VT

Cleanup Activities

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Background

The 38-acre Pine Street Canal site consists of a canal and turning basin, adjacent wetlands, an area formerly known as Maltex Pond, and an additional portion of land. Around 1908, a coal gasification plant began operating on Pine Street, southeast of the canal. The plant ceased operations in 1966. Plant wastewaters and residual oil and wood chips saturated with organic compounds were directly discharged or disposed of in the Pine Street Canal wetland. During the 1960s and 1970s, an oil-like material was detected seeping from the wetland into Pine Street Canal, the turning basin, and Maltex Pond. The State detected high levels of organic compounds associated with coal tar at several locations while investigating the site for a then proposed major highway. The State was concerned that construction would release organic compounds into the canal and possibly into Lake Champlain, the source of Burlington's drinking water. The area is surrounded by large and small businesses. There are several single and multiple-family dwellings, including apartment buildings, located within 1 mile of the site. Burlington has a population of approximately 39,100.

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What Has Been Done to Clean Up the Site?

In 1985, EPA undertook an emergency removal of coal tar, capping of the Maltex Pond area, and construction of gates at key access points to reduce exposure to hazardous substances. A ROD for the site cleanup was signed in September 1998. In November 1999, a Consent Decree between EPA, Department of Justice (DOJ), and twenty-one potentially responsible parties was lodged in Federal Court. The remedy which included capping eight acres of contaminated sediments, habitat restoration, long-term operation and maintenance, and compliance monitoring, was completed in 2004. Deed restrictions to ensure that the site is not used in a way so as to expose the waste left in place and/or adversely affect the remedy, were recorded in July 2006. The first five-year review was completed in October 2006; the second was completed in December 2011, and an addendum was completed in August 2014. The parties responsible for the remedy constructed an amended cap in 2010 to address releases of oil and coal tar seeping through the existing sand cap at the southern end of the canal. In 2012 - 2013, the parties also installed a subsurface vertical barrier and monitoring wells at the northwestern corner of the Site, to prevent the potential for possible migration of contaminants into Lake Champlain. EPA and the VT Department of Environmental Conservation will continue to oversee the project.

The site is being addressed in two stages: emergency actions and a long-term remedial phase focusing on cleanup of the entire site.

Emergency Actions
In 1985, the EPA excavated 500 cubic yards of coal tar, solidified it, and disposed of it in an approved facility. The Maltex Pond area also was capped with clay and covered with topsoil and seeded. A temporary fence was erected, warning signs were posted, and sampling was conducted.
 
Entire Site
By early 1991 the EPA had conducted field investigations, including a soil gas survey, a geophysical survey, air sampling, ecological studies, surface water and sediment sampling, soil sampling, installation of monitoring wells, and groundwater sampling to determine the nature and extent of the site contamination. Treatability studies to aid in remedy selection were completed in 1992. An investigation to determine cleanup alternatives was completed in late 1992 and the EPA proposed a cleanup plan. The cleanup plan was withdrawn in 1993 in response to the comments received during the public comment period. Additional studies focusing on ecological risk and contaminant migration were then completed by the potentially responsible parties. The EPA completed a supplemental ecological risk assessment based on new data. EPA evaluated alternative cleanup measures in late 1997 thru 1998. A cleanup proposal was released for public comment in June 1998. A Record of Decision (ROD) was signed on September 29, 1998. The ROD contains the remedy supported by the public. Elements of the remedy include, capping contaminated sediments in portions of the canal, turning basin and adjacent wetlands, institutional controls to prohibit potable use of groundwater below the site, institutional controls for certain land-use development such as residential and children's day care center, site boundary definition to allow for redevelopment of certain adjacent parcels, long term performance monitoring, and five year reviews.

Historic Resources
It has been determined that sunken barges in the canal and other features at the site are eligible for the National Register of Historic Places. EPA, the Vermont State Historic Preservation Officer, and the Peforming Defendants agreed to a mitigation plan for the damages to these historic resources that will be incurred as a result of implementing this remedy. Under the plan, the Lake Champlain Maritime Museum (LCMM) studied another sunken barge of similar type, this one in Lake Champlain proper near Charlotte, VT. Field work on the barge, called the Sloop Island Canal Boat, was conducted during the summers of 2002 and 2003. The artifact collection removed from the canal boat includes such items as vessel rigging, cooking utensils, crocks, tools, bottles, canning jars, clothing and jugs. All of the recovered artifacts were analyzed, photographed, drawn and conserved at LCMM's Conservation Laboratory. Many items from the collection can be viewed in the Sloop Island Canal Boat exhibit at the LCMM in Vergennes, VT. See below for a link to Sloop Island Canal Boat Study: The Archaeology of a Champlain Canal Boat and the Pine Street Barge Canal, an educational booklet produced by LCMM. Additional information about this project can be found by visiting www.lcmm.org

First Five Year Review
The first five year review of the remedial action was completed in October 2006. The remedy is currently protective of human health and the environment except for ongoing release of coal tar in a limited area of the subaqueous cap in the canal. Absorbent booms placed across the canal have prevented contamination from entering Lake Champlain while a more permanent solution could be designed and constructed. The remedy will not be protective in the future without a mechanism in place to monitor to determine compliance with institutional controls that have been established to restrict land and groundwater use at the site. Two issues that must be evaluated in order to determine protectiveness in the future are: 1) the vapor intrusion to indoor air pathway and the potential to impact current or future indoor receptors and 2) the ability of the existing compliance monitoring program to adequately monitor performance standards for contaminant migration given new site conditions.

Amended Cap
In April 2009, after a 30-day public comment period, EPA issued an Explanation of Significant Differences which modifies the remedy selected in 1998. Although the remedy is working effectively to isolate contaminants in the canal sediments over most of the site, oil and coat tar were breaking through the underwater sand cap at the southern end of the canal. In areas where seepage was occurring, the sand cap was replaced with a cap that contains a material that will capture the oil and coal tar before it is released into the canal. Over time, the new cap will fill up and have to be replaced. To extend the life of the new cap, several passive recovery wells were installed along the banks of the canal. Oil and coal tar that accumulate in the recovery wells will periodically be removed and shipped off site for treatment or disposal at an approved facility. Construction of the amended cap was completed in December 2010.

Vertical Barrier
In September 2011, after a 30-day public comment period, EPA issued a second Explanation of Significant Differences. A component of the containment remedy selected in 1998 was a groundwater monitoring program, the purpose of which was to ensure that dissolved contaminants in the groundwater do not migrate beyond the site boundary. For nearly ten years, the groundwater plume was stable. However, since 2008, increases in benzene concentrations in groundwater samples along with the intermittent presence of measurable accumulations of coal tar in several monitoring wells on the lake side of the canal at the northern end of the site indicate that additional containment is needed. To protect Lake Champlain from potentially being impacted by the migration of contaminated groundwater and coal tar left on site, a 200-300 foot long vertical barrier and passive recovery wells were installed in 2012 to 2013, and a monitoring program is in place.

Second Five Year Review
The second five year review of the remedial action was completed in December 2011. While the remedy is protective for most pathways of exposure to contaminants, a protectiveness determination could not be made until further information was obtained to evaluate potential vapor intrusion impacts at the Burlington Electric Department (BED) building, located just south of the original manufactured gas plant. In addition, in order for remedy to be protective in the long-term, it was necessary to construct the vertical barrier, described above.
 
Five Year Review Addendum
In response to EPA deferring a statement of remedy protectiveness in the second five year review, the Pine Street Canal Performing Defendants undertook a soil gas and groundwater study at 585 Pine Street. Based on an evaluation of those data, EPA made the determination, with the concurrence of the State of Vermont, that there are no unacceptable risks to human health in the BED building due to the vapor intrusion pathway. In August 2014, EPA issued an addendum to the second five year review stating the following: a) the remedy is protective in the short term, and b) for the remedy to remain protective in the long term, future data collection (e.g., soil gas, groundwater) and a new assessment of the vapor intrusion pathway may be required to demonstrate that conditions at the Site have not changed.

Third Five Year Review
The third five year review of the remedial action was completed in December 2016.   The remedy remains protective of human health and the environment.  The next review will be conducted in 2021.

Enforcement Highlights
In 1993, a Coordinating Council was formed to address the complex issues regarding the cleanup of this site. The group, under the direction of a neutral facilitator, includes EPA, the State, the potentially responsible parties, the U.S. Fish and Wildlife Service, the city, and environmental and community groups. Working as an EPA pilot project for more effective community involvement the group planned additional studies to fill data gaps and recommended a final cleanup remedy to the EPA. The remedy selected by the EPA in the ROD is the plan recommended by the coordinating council.

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What Is the Current Site Status?

The 1998 Record of Decision (ROD) called for the placement of a subaqueous cap in the canal to address risk to ecological receptors; long term monitoring; and the imposition of land use restrictions on the site to prevent migration or unacceptable human exposure to contaminants. The remedy was implemented in two phases. The first involved the installation of a weir where the canal empties into Lake Champlain. The weir will maintain desired water levels in the canal to prevent future erosion of the subaqueous cap. Construction of the weir was completed in November 2001. The second phase involved capping contaminated soils at the southern end of the site, placing the subaqueous cap over contaminated sediments in the canal and turning basin, making improvements to the stormwater control system, and wetlands restoration. Work began in July 2002, and was completed in March 2003. In June 2003, a breakout of coal tar and oil was discovered in an uncapped area immediately adjacent to, but not in, the canal. During the summer of 2004, the sand cap was extended over a portion of the canal's west bank where coal tar and oil was being released to the ground surface via macropores (e.g., historic cribbing, root system of dead trees). The expanded cap appeared to address the release of contamination until oily sheens and globules of coal tar were observed floating on the surface water at the southern end of the canal during routine compliance monitoring in the spring of 2005. Subsequent studies conducted by the parties responsible for the implementation of the cleanup, under the supervision of EPA and VT DEC, concluded that the coal tar and oil is migrating upwards through the sand cap, primarily when gas bubbles are released from the peat below the cap. Absorbent booms placed across the canal have prevented contamination from entering Lake Champlain while a more permanent solution could be designed and constructed.

In April 2009, after a 30-day public comment period, EPA issued an Explanation of Significant Differences (ESD), modifying the remedy to include an amended cap at the southern end of the canal that will capture the oil and coal tar before it is released to the canal. Construction was completed in December 2010. Over time the new cap will fill up and have to be replaced. To extend the life of the new cap, several passive recovery wells were installed along the banks of the canal, which will also prevent contamination from migrating into the canal. Oil and coal tar that accumulates in the recovery wells will periodically be removed and shipped off site for treatment or disposal at an approved facility.

In September 2011, after a 30-day public comment period, EPA issued a second ESD modifying the remedy. For nearly ten years, the groundwater plume beneath the site was stable. However, since 2008, increases in benzene concentrations in groundwater samples along with the intermittent presence of measurable accumulations of coal tar in several monitoring wells indicate that additional containment is needed. To protect Lake Champlain from potentially being impacted by the migration of contaminated groundwater and coal tar left on site, a 200-300 foot long vertical barrier and passive recovery wells were installed during 2012 - 2013.

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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.

Institutional controls are required for this site.
 
This site requires ICs because a decision document, such as a Record of Decision, has documented some level of contamination and/or remedy component at the site that would restrict use of the site. These ICs are required to help ensure the site is used in an appropriate way and that activities at the site do not damage the cleanup components. These ICs will remain in place for as long as the contamination and/or cleanup components stay on site. The site contacts should be consulted if there are questions on the ICs for this site.
 
The following IC Instruments provide media-specific use restrictions that have been implemented by EPA for protecting human health, the environment and remedial engineering on this site. Instruments are documents used by EPA or other organizations to implement the use restrictions at a site. To know about other media-specific use restrictions that are planned but not implemented at this site, please contact the Regional Office using the Site Contact listed above.
 
Click here for IC Instruments implemented for this site.

To contact EPA regarding Institutional Controls and/or activity and use limitations, please complete this form.

ICs are generally defined as administrative and legal tools that do not involve construction or physically changing the site. Common examples of ICs include site use and excavation restrictions put in place through State and local authorities like zoning, permits and easements. ICs are normally used when waste is left onsite and when there is a limit to the activities that can safely take place at the site (i.e., the site cannot support unlimited use and unrestricted exposure) and/or when cleanup components of the remedy remains onsite (e.g., landfill caps, pumping equipment or pipelines). Effective ICs help ensure that these sites can be returned to safe and beneficial use.
 
Disclaimer: This information is being provided by EPA as an informational tool to further assist the public in determining the types of restrictions that may be in place at National Priorities List sites being addressed by EPA under the Superfund program. In addition to the areas addressed by the institutional controls identified on this web site there may be other areas on the property that require restrictions on use of the property that are not captured in this EPA database. States and other entities may have implemented laws or restrictions applicable to this site. The information provided herein does not replace a title search or meet "All Appropriate Inquiry" requirements. U.S. EPA encourages users to review the Site files to obtain information regarding remedy components, containment systems and the land use for which cleanup standards were selected for these sites. More information and links can be found in the Institutional Control instrument collection of document, above, and the EPA regional offices may also be contacted.

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