Recent Trends in the Selection of Remedies at Superfund Sites

The U.S. Environmental Protection Agency (U.S. EPA) recently issued the 15th edition of its Superfund Remedy Report (SRR).  The report is a compilation of over 300 remedies selected in decision documents for contaminated sites on the National Priorities List (NPL) from October 2011 to September 2014.


Remedies included in the document relate to soil, groundwater, and sediment.  The remedies were counted by specific technology or approach, and also grouped into categories, such as treatment, on-site containment, off-site disposal, monitored natural attenuation (MNA), and institutional controls (ICs). The study analyzed remedies by media (i.e., soil, sediment, and groundwater), and the types of contaminants of concern (COCs) in those media. The evaluation also included vapor intrusion mitigation remedies.

The SRR compiles data on remedies and presents separate analyses for contaminants overall and contaminants in select media (soil, sediment and groundwater). This edition also includes a separate analysis of remedy and response action data for large sediment sites.

Dredging PCB-Contaminated sediment on the Hudson River

For the majority (78 percent) of the 1,540 Superfund sites with decision documents available, treatment has been selected, often in combination with other remedies. Most of these sites have more than one contaminated media, most frequently groundwater and soil. Most sites also have different types of contaminants of concern (COCs): more than half of sites address volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs) and metals, while a quarter of sites address two of these groups.

For FYs 2012 to 2014, remedies were selected in 308 decision documents, including 242 RODs and ROD Amendments, and 66 ESDs with remedial components. Of the 308 decision documents, 188 (61 percent) include a remedy for source materials (such as soil and sediment) and 160 (52 percent) for groundwater. Remedies were also selected for soil gas and air related to vapor intrusion.

Source Remedies

For this three-year period, nearly half of decision documents with source remedies include treatment. A quarter of all source decision documents include in situ treatment. Soil vapor extraction, chemical treatment, and in situ thermal treatment are the most frequently selected in situ treatment technologies for sources with soil being the most common source medium addressed. Physical separation, recycling, and solidification/stabilization (S/S) are the most common ex situ treatment methods. Metals, polycyclic aromatic hydrocarbons (PAHs) and halogenated VOCs are the COCs most commonly addressed.

Table 1: Summary of Source Control Remedies

• Chemical, biological, or physical means to reduce toxicity, mobility, or volume of contaminated source media

• Can be either in situ or ex situ

• examples include chemical treatment and in situ thermal treatment

On-site containment
• Examples include the use of caps, liners, covers, and landfilling on site
Off-site disposal
• Includes excavation and disposal at an off-site facility
Monitored natural attenuation (MNA)
• Reliance on natural processes

• Natural attenuation processes may include physical, chemical, and biological processes

Monitored natural recovery (MNR)
• Reliance on natural processes to reduce risk from sediments

• Natural attenuation processes may include physical, chemical, and biological processes

Enhanced monitored natural recovery (EMNR)
• Combines natural recovery with an engineered approach for sediments

• Typically includes placing a thin layer of clean sediment to accelerate the recovery process

Institutional controls
• Nonengineered instruments, such as administrative and legal controls, that help minimize the potential for human exposure to contamination and protect the integrity of the remedy

• Examples for source media include land use restrictions and access agreements

• Source control remedies that do not fall into the categories of source control treatment, on-site containment, off-site disposal, MNA, MNR, EMNR, or engineering controls

• Examples include wetlands replacement and shoreline stabilization

Sediment Remedies

Of the 188 recent source decision documents, 39 include a remedy for sediments. Most of the sediment decision documents (87 percent) include dredging, excavation, off-site disposal or on-site containment as part of the selected remedy. Some treatment was also selected — for example, in situ amended caps and ex situ and in situ S/S. Examples of other remedies include wetlands replacement and enhanced or monitored natural recovery (EMNR or MNR). Two-thirds of the sediment decision documents include institutional controls (ICs). Metals, PAHs and polychlorinated biphenyls are the COCs most frequently addressed.

EPA also analyzed newly acquired remedy and response action data on the largest sediment sites, known as Tier 1 sediment sites. The data include 112 actions for 66 sites. Some of these actions have progressed to design or implementation. Most remedies for these sites include dredging and excavation (84 percent), 48 percent include residual caps, and 29 percent include engineered caps designed to isolate contaminants from the waterway. A quarter of the Tier 1 sites include MNR and 18 percent include EMNR.

The U.S. EPA analyzed the contaminants of concern (COCs) addressed by sediment remedies in recent decision documents.  Over three-quarters of these documents include metals. PCBs and PAHs are the next most frequent categories of COCs with 44 percent each, as seen in the Figure below.

Figure 1: Detailed COCs in Decision Documents with Sediment Remedies

Groundwater Remedies

For the 160 groundwater decision documents signed in FYs 2012 to 2014, the groundwater remedies continue to be primarily a mix of in situ treatment, pump and treat (P&T), and monitored natural attenuation; most also include ICs. The use of in situ groundwater treatment continues to rise and is now selected in over half of groundwater decision documents. Of these, bioremediation and chemical treatment remain the most frequently selected. The majority of in situ bioremediation remedies specify anaerobic bioremediation, and more than half of chemical treatment remedies specify in situ chemical oxidation. The selection of P&T in groundwater decision documents has decreased significantly since the early 1990s and reached its lowest, 17 percent, in FY 2014. Containment technologies (vertical engineered barriers such as slurry walls) were selected at a few sites. By far, halogenated VOCs (primarily chlorinated VOCs) are the most common type of groundwater COC, addressed in 72 percent of recent groundwater decision documents.

Table 2. Summary of Groundwater and Vapor Intrusion Remedy Categories

In situ treatment
• Treatment of groundwater in place without extraction from an aquifer

• Examples include in situ chemical oxidation and in situ bioremediation

Pump and treat (P&T)
• Pumping of groundwater from a well or trench, followed by aboveground treatment

• Examples of aboveground treatment include air stripping and granular activated carbon

Monitored natural attenuation (MNA)
• Reliance on natural attenuation processes

• Natural attenuation processes may include physical, chemical, and biological processes

• Containment of groundwater using a vertical, engineered, subsurface, impermeable barrier
Institutional controls
• Examples include drilling restrictions and water supply use restrictions
Alternative water supply
• Examples include installing new water supply wells, providing bottled water or extending a municipal water supply
• Groundwater remedies that do not fall into the categories of in situ treatment, P&T, MNA, containment, institutional controls, or alternative water supply

• Examples include drainage/erosion control and wetlands restoration

Vapor intrusion
• Mitigation of soil gas or indoor air to reduce exposure to vapor contamination in buildings

• Examples include active depressurization technologies and passive barriers

Institutional controls
• Examples include land use restrictions and vapor intrusion mitigation for new buildings

Vapor Intrusion Remedies

EPA selected vapor intrusion mitigation for existing structures in nine of the recent decision documents, and ICs for either existing structures or future construction in 34 of these documents. Some ICs restrict the future use of structures to avoid vapor intrusion exposure and others require the installation of mitigation systems as part of future construction. Active depressurization was the most common mitigation method specified, followed by passive barriers and subslab ventilation systems.

Combined and Optimized Remedies

In this report, the U.S. EPA also discusses the use of combined remedies and optimization reviews. The combined remedy highlights provide examples of recent decision documents where remedies are combined spatially or in sequence. The optimization highlights provide examples of how optimization efforts have informed remedy decisions in recent decision documents.

The remedy and site information provided in this report can help identify program needs for expanded technical information and support. For example, growing use of in situ groundwater technologies suggests the need for additional knowledge and support associated with those technologies. This analysis also provides information of value to stakeholders including technology developers; consulting and engineering firms; and federal, state, and tribal remediation professionals. In particular, developers and service providers can gain insight into the demand for specific remedial technologies.


The analysis of most recent Superfund decision documents shows continued selection of a full range of treatment, containment, and disposal technologies and approaches for both source material and groundwater. Selection of some remedies is increasing in frequency (such as in situ groundwater technologies), while others are decreasing (such as pump-and-treat). Remedial approaches, including in situ bioremediation, are often combined in time or space to address different areas of the site or applied sequentially. Remedy optimization and reevaluation has resulted in changes to previously selected or implemented cleanup approaches. Overall, most Superfund sites contain different types of COCs: more than half of sites with remedies address VOCs, SVOCs, and metals/metalloids, and almost a quarter of sites address two of these groups.



U.S. EPA Sees New Challenges Ahead for Superfund

by  Loren R. Dunn and Eric L. Klein, Beveridge & Diamond PC

The U.S. EPA released a four-year “strategic plan” in mid-February that continues to emphasize the Superfund program as one of Administrator Scott Pruitt’s top priorities.  While it has been clear since last summer’s Superfund Task Force report that the agency’s new leadership wants to accelerate Superfund site cleanups, the agency’s new strategic plan reveals for the first time that the U.S. EPA also sees emerging challenges ahead for Superfund.

“A number of factors may delay cleanup timelines,” the agency wrote in its strategy document.  These factors include the “discovery of new pathways and emerging contaminants” such as vapor intrusion and per- and polyfluoroalkyl substances (PFAS), and new science such as “new toxicity information or a new analytical method.”

Photo Credit: Michael Paulsen / Houston Chronicle

According to the strategic plan, the emergence of this kind of new information can reopen previously settled remedy determinations – and the Superfund sites that still remain on the National Priorities List (NPL) already tend to be the harder cases, with more difficult patterns of contamination and more complex remedies.  The U.S. EPA flagged in particular its waste management and chemical facility risk programs, where “rapidly changing technology, emerging new waste streams, and aging infrastructure present challenges[.]”

It remains to be seen whether the agency’s cautions in the Superfund section of its strategy document represent a meaningful shift in the agency’s frequently-stated intention to reinvigorate the Superfund program.  Early in his tenure, Mr. Pruitt charged his Superfund Task Force with generating a series of recommendations centered around Mr. Pruitt’s goals for Superfund: faster cleanups, the encouragement of cleanup and remediation investments by PRPs and private investors, and a process centered on stakeholder engagement and community revitalization.  In December 2017, in response to one of the Task Force’s recommendations, the agency released a list of 21 high-priority NPL sites that Mr. Pruitt targeted for “immediate and intense attention,” according to an U.S. EPA press release.  The cautionary notes in this week’s strategic plan are a subtle shift in tone for the U.S. EPA.

At the same time, the document also sets forth a plan for improving the consistency and certainty of EPA’s enforcement activities in the regulated community.  It remains to be seen how U.S. EPA intends to achieve consistency while being responsive to state and tribal interests.

These goals, of course, will depend on the details of implementation, which are not set forth in the strategic plan.  And such details will depend on the agency’s budget, which remains in flux for 2019 and beyond.  For example, U.S. EPA’s proposed budget for fiscal year 2019 sought a roughly $327 million cut in the Superfund program, but the funds were added back into the budget proposal as part of last-minute budget agreement reached in Congress last week, securing the program’s funding in the short-term.   Last year, the administration proposed a 30% cut in the agency’s funding  but Congress balked and eventually approved a budget that cut roughly 1%.


About the Authors

Loren R. Dunn represents regional and national companies at locations throughout the country in environmental regulation and litigation issues.  Loren’s environmental projects have involved hazardous waste and large multi-party toxics cleanup sites, including marine and fresh water sediment sites, landfills, and natural resource damages claims. He has also conducted extensive work obtaining permits for key facility operations. He has particularly deep knowledge of the following industries: manufactured gas facilities, regulated utilities, smelters and metals refineries, pesticide sites, and large area contamination sites.

Eric L. Klein is an environmental civil litigator and regulatory counselor in the Washington, D.C. office of Beveridge & Diamond, P.C.  He has handled cases in state and federal courts throughout the United States, litigating a variety of complex civil and commercial matters before juries, trial and appellate courts, arbitrators and administrative tribunals.  Mr. Klein frequently litigates both statutory and common law claims, and specializes in challenging and defending technical experts in the litigation of complex environmental torts.

This article was first published on the Beveridge & Diamond PC website.

U.S. EPA Targets Superfund Sites for Immediate Clean-up

The United States Environmental Protection Agency (U.S. EPA) recently released a list of Superfund Sites targeted for immediate, intense action, as of December 8th 2017. The list is a response to July’s Superfund Task Force Recommendations. The U.S. EPA considers the sites listed to benefit from Administrator Scott Pruitt’s direct engagement, requiring timely resolve of specific issues to streamline cleanup and redevelopment and protect human health and the environment.

3D Image of NAPL contamination at the B.F. GOODRICH facility in Calvert City, KY

The list, spanning all ten EPA regions across the United States, with accompanying plans, issues, and categorizations associated with each site, can be found here.

As reported in the Washington Post, the push is part of Administrator Scott Pruitt’s promise to prioritize the decades-old cleanup program, even as the Trump administration shrinks the size and reach of the EPA. The 21 sites highlighted by the agency span the country, from a former tannery site in New Hampshire to a contaminated landfill from the World War II-era Manhattan Project in St. Louis to an abandoned copper mine in Nevada.

“By elevating these sites, we are sending a message that EPA is, in fact, restoring its Superfund program to its rightful place at the center of the agency’s mission,” Pruitt said in a statement. “Getting toxic land sites cleaned up and revitalized is of the utmost importance to the communities across the country that are affected by these sites.”

The U.S. EPA said that it developed the list using sites “where opportunities exist to act quickly and comprehensively.” Notably, the agency also acknowledged that “there is no commitment of additional funding associated with a site’s inclusion on the list.”

U.S. EPA Settlement with UConn resolves Improper PCB Disposal Activity

The University of Connecticut has taken steps to ensure its PCB waste is properly disposed of in the future to settle claims by the U.S. Environmental Protection Agency (U.S. EPA) that it improperly disposed of PCBs during a 2013 renovation project at its Storrs campus.

An aerial view of the Storrs Campus on Oct. 9, 2013. (Peter Morenus/UConn Photo)Morenus/UConn Photo)

The university disposed of the waste containing polychlorinated biphenyls during a 2013 window replacement project in violation of the federal Toxic Substances Control Act.  Working with its contractors and an environmental consultant, UConn’s renovation project led to the removal of soils contaminated with PCBs from the window caulk, which are classified as PCB “remediation waste.” PCB remediation waste can be disposed of only at approved facilities, but the transportation manifest did not identify the material as such, and the material consequently was shipped to a facility not licensed for this disposal.  Earlier this year, EPA notified UConn of its potential liability under federal law.  UConn and EPA then reached an agreement to resolve the violation. UConn will also pay a penalty of $28,125 as part of this settlement.

“This action demonstrates how important it is that all parties involved with PCB waste ensure that every step in the handling and disposal of the PCBs is done consistent with the regulations,” said Deb Szaro, acting regional administrator of EPA’s New England office.  “EPA appreciates the steps UConn has taken to minimize future violations.”

Once in the environment, PCBs do not readily break down and therefore may remain for long periods of time, cycling between air, water, and soil.  PCBs are classified by EPA as a probable human carcinogen and have been shown to cause other adverse health effects on the immune system, reproductive system, nervous system, and endocrine system.

For more information about health concerns and safe handling practices for PCBs (

SOURCE: U.S. Environmental Protection Agency