Starting in 1985, comprehensive Remedial Action Plans were initiated to restore impaired beneficial uses in Great Lakes Areas of Concern. These plans were a catalyst for developing programs to remediate contaminated sediments. In 1987, the U.S. Environmental Protection Agency implemented the Assessment and Remediation of Contaminated Sediment Program to: measure contaminant concentrations in sediments and their potential effects on aquatic life; evaluate risks to wildlife and human health; and test technologies that might be used to clean up these contaminated sediments. In 2002, the U.S. Great Lakes Legacy Act was signed into law with the intent to remediate contaminated sediments at Great Lakes Areas of Concern. Before Great Lakes Legacy Act, only limited progress had been made in addressing contaminated sediments, a major, intractable issue impacting 9 of the 14 listed beneficial use impairments in Areas of Concern. Between 2004 and 2017, Great Lakes stakeholders have completed a total of 46 contaminated sediment remediation projects in U.S. Areas of Concern, resulting in the remediation of over 6.6 million m3 of contaminated sediments at a cost of over $1 billion. Although much has been accomplished, more contaminated sediment remediation must be undertaken to fully restore Areas of Concern. The Great Lakes Legacy Act and Great Lakes Restoration Initiative have been essential components for completing this important remediation and restoration work in Areas of Concern that is resulting in significant economic and environmental benefits.
Contaminated sediments are a significant problem in the Great Lakes basin (Zarull et al., 1999). Since the signing of the 1972 Great Lakes Water Quality Agreement and up through the mid-1980s, the governments of the U.S. and Canada, the eight Great Lakes states, and the Province of Ontario, were substantially involved in contaminated sediment issues through the International Joint Commission (IJC) (Table 1). The IJC provided guidance to the Parties and performed their review and evaluation role of federal government activities and programs.
In 1985, as a result of a recommendation of the IJC’s Great Lakes Water Quality Board, the Parties, in cooperation with the jurisdictions, committed to developing and implementing Remedial Action Plans (RAPs) to restore impaired beneficial uses in each Area of Concern (AOC) within their jurisdictional boundaries (IJC, 1985). This commitment to RAPs was then codified in the 1987 Protocol to the Great Lakes Water Quality Agreement. In many respects, RAPs became a catalyst for the development of contaminated sediment programs by federal, state, and provincial governments.
Prior to the mid-1980s, there were no comprehensive federal, state, or provincial programs to address contaminated sediment. It should be noted that dredging for navigational purposes, to keep shipping channels open, resulted in a secondary benefit of removing some contaminated sediments. Governments and RAP groups quickly discovered that: the severity and geographic extent of contaminated sediments was not well understood; contaminated sediment problems were not quantitatively coupled to use impairments; remedial technologies were limited in scope; and stakeholders lacked a basis for determining how much sediment to clean up and what environmental/ecological improvements to expect over time. RAPs helped catalyze the scientific assessment of the severity and geographic extent of contaminated sediments in AOCs and the identification of scientifically-defensible options to remediate contaminated sediment.
In 1987, in response to concern for contaminated sediments in the Great Lakes, the U.S. Congress authorized a five-year study and demonstration project to identify the best techniques for addressing contaminated sediments. Additionally, the 1987 Protocol to the Great Lakes Water Quality Agreement directed the Parties to establish methods to quantify, manage, and remediate contaminated sediments (Canada and the U.S., 1987; White, 1998). As a result of these two policies, the U.S. Environmental Protection Agency (EPA) created the Assessment and Remediation of Contaminated Sediment (ARCS) Program. The aims of ARCS were to: measure concentrations of contaminants at chosen sites on the Great Lakes; recommend approaches to gauge the effects of these contaminants on aquatic life; recommend approaches to assess risks to wildlife and human health posed by the contaminants; and test technologies that might be used to clean up these contaminated sediments. Although the ARCS program significantly added to the scientific understanding of sediment assessment and remediation techniques, federal and state enforcement programs were primarily responsible for progress in remediating contaminated sediment in AOCs. In 2002, U.S. EPA's Great Lakes Legacy Act (GLLA) was signed into law with the specific intent to expedite projects to remediate contaminated sediments in Great Lakes AOCs. Again, prior to 2002, removal and disposal of contaminated sediment was only a secondary benefit of dredging for navigational purposes that primarily focused on maintaining or increasing the depth of navigational channels for shipping. Enforcement programs were an additional tool that legally enforced responsible parties to remediate contaminated sediment that they had caused. GLLA focuses on “legacy” contaminated sediment where there is no potentially responsible parties.
Since the onset of ARCS and the enactment of GLLA, federal and state agencies, environmental groups, industries, and local citizens have worked together to identify contaminated sites, develop remediation plans, and restore the sediments to safe levels for the ecosystem. The purpose of the paper is to provide a brief overview of U.S. EPA’s programmatic efforts to assess and remediate contaminated sediments in AOCs, document progress in contaminated sediment remediation, present four case studies, and share some practical lessons learned.
Contaminated sediment program and assessment methods
Although significant progress had been made since the 1970s in reducing the discharge of persistent, toxic chemicals into the Great Lakes, high concentrations of contaminants were still in the bottom sediments of rivers and harbors. These contaminated sediments have raised considerable concern over the potential risks to aquatic organisms, wildlife, and humans (Zarull et al, 2002). As a result, fish consumption advisories are in effect in most AOCs around the Great Lakes (Zarull et al, 1999).
Through U.S. EPA’s ARCS Program, considerable effort has gone into assessment of the severity and geographic extent of contaminated sediment problems, evaluating remedial options, and selecting appropriate remedial actions. Detailed methods were developed to assess the nature and extent of sediment contamination in Great Lakes AOCs, quantify ecological impacts, assess biomagnification in food webs, evaluate risks, and evaluate technologies to remedy such contamination (U.S. EPA, 1994). It should also be noted that in addition to potential ecological damage attributed to contaminated sediments, there were also economic concerns in that contaminated sediment could impact the viability of commercial ports because of restrictions on navigational dredging and the disposal of dredged sediments (Zarull et al., 2001). New bioassessment tools have also been developed to evaluate and manage contaminated sediments, including assessment of the similarity to reference community assemblages, toxicity, biomagnification, etc. (Krantzberg et al, 2000; Hartig et al, 2004; Chapman and Anderson, 2005).
In general, U.S. EPA typically uses a two-phased sediment assessment approach:
The first phase includes a comprehensive sampling of the entire AOC to help pinpoint the location of “hot spots;” and
The second phase works in the “hot spots” to perform more detailed chemical and biological analyses to provide sufficient information for making potential sediment remediation decisions.
The overall goal is to generate the information needed to make scientifically-defensible remediation decisions. The U.S. EPA works closely with state agencies and local communities involved in the RAP process in developing sampling plans, testing protocols, and Quality Assurance Project Plans for individual projects. The U.S. EPA provides technical, financial, and field support for federal, state, and tribal partners to assist in addressing contaminated sediments with the work aimed towards reaching remedial decisions and environmental restoration.
Progress in cleaning up contaminated sediments
Contaminated sediment is a known problem in 37 of the 43 AOCs (United States and Canada, 2016). In the U.S., the GLLA and enforcement programs are the primary tools to clean up contaminated sediments in AOCs. Although the GLLA was initially a five-year funding authority (U.S. Congress, 2002), the program was extended in 2008 (U.S. Congress, 2008) and the Great Lakes Restoration Initiative currently provides funding to implement contaminated sediment cleanup projects under the GLLA. Indeed, this Act and Initiative have clearly accelerated contaminated sediment cleanups since their inception in 2002 and 2010, respectively (Figure 1). Prior to 2002, some contaminated sediment was removed and contained via dredging programs of the U.S. Army Corps of Engineers established to maintain depths of shipping channels. In addition, there were a few sediment remediation projects implemented as a result of enforcement actions on responsible parties. Following the onset of GLLA and Great Lakes Restoration Initiative, contaminated sediment cleanup accelerated with 16 projects implemented in 2002-2010 and 30 projects implemented in 2011-2017 (Figure 1).
In total, there have been 46 contaminated sediment remediation projects undertaken in U.S. AOCs between 2004 and 2017, remediating over 6,600,000 m3 of contaminated sediment at a cost of approximately $1.2 billion (Table 2). This acceleration of sediment remediation projects has provided significant benefits towards completing required management actions at U.S. AOCs. Since the inception of the Great Lakes Restoration Initiative, all necessary remedial actions, including contaminated sediment remediation, have been completed in the Sheboygan River (Wisconsin), Waukegan Harbor (Illinois), Ashtabula River (Ohio), Menomonee River (Wisconsin and Michigan), River Raisin (Michigan), White Lake (Michigan), Deer Lake (Michigan), Rochester (New York), and St. Clair River (Michigan) AOCs in the United States. In addition, numerous other sediment remediation projects are planned for implementation under GLLA over the next few years. These projects will help contribute to delisting additional AOCs. The GLLA and Great Lakes Restoration Initiative programs can assist in completing these future cleanups in all AOCs and lead to significant environmental and economic benefits.
River Raisin AOC case study
The River Raisin AOC is located in Monroe County, Michigan on western Lake Erie. It was originally designated an AOC in 1985, primarily due to PCBs in sediments. In 1997, Ford Motor Company removed 20,000 m3 of highly PCB-contaminated sediment from the AOC, under U.S. EPA oversight. From 1998-2002, the U.S. EPA and the Michigan Department of Environmental Quality (MDEQ) performed post-remediation sediment monitoring, finding that high levels of PCBs remained in both the sediments and in fish tissue. PCB contamination caused the following beneficial use impairments: restrictions on fish and wildlife consumption, bird or animal deformities or reproductive problems, and restrictions on dredging activities.
In 2012, the U.S. Army Corps of Engineers performed a strategic navigational dredging project that removed 52,750 m3 of PCB-contaminated sediment. Additional sediment remediation took place in 2012-2013 and 2016 under the GLLA, in partnership with Ford Motor Company and the MDEQ. Methods employed included mechanical dredging, hydraulic dredging, and capping. In total, 95,350 m3 of PCB-contaminated sediment were removed and disposed (completed in 2016). MDEQ and Ford provided cash and in-kind services of over $15.4 million under the GLLA cost-sharing agreement. The contaminated sediment was transported to a disposal facility certified to handle contaminated material in Wayne County, Michigan. Partners in the project included: U.S. EPA, MDEQ, and Ford Motor Company.
Since 2010, U.S. EPA has provided more than $27 million in Great Lakes Restoration Initiative funding to accelerate implementation of actions to restore the River Raisin AOC, including aquatic habitat restoration projects and dam removal or retrofitting to support upstream fish migration, in addition to the contaminated sediment remediation projects. These Great Lakes Restoration Initiative funds have leveraged an additional $18 million in state and private funding for AOC work. The federal, state, local, and private partnerships on Great Lakes Restoration Initiative projects have remediated over 144,000 m3 of contaminated sediment, restored over 121 ha of aquatic habitat, and opened up an additional 36.8 km of the River Raisin to fish migration and spawning. All remedial actions identified for use restoration in the RAP have now been implemented.
Sheboygan River Area of Concern case study
In 1985, the lower 22.4 km Sheboygan River and its harbor in Sheboygan, Wisconsin were designated an AOC. The primary cause was contaminated sediment from historical, industrial waste – polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs).
The worst areas of contamination in the Sheboygan River were designated as Superfund sites. The Superfund Program is a long-term, cleanup program for uncontrolled hazardous waste. Phase 1 Sheboygan River and Harbor Superfund Site cleanup was completed in 2004. Phase 2 Sheboygan River and Harbor Superfund Site cleanup was completed in 2007. These two Superfund cleanups laid the foundation for the GLLA cleanup.
In 2012, U.S. EPA completed a GLLA project that removed 113,000 m3 of contaminated sediment. A separate U.S. EPA strategic navigational dredging project was completed in 2013 where over 118,000 m3 of contaminated sediment was removed from the Inner Harbor between the 8th Street Bridge and the river mouth. All contaminated sediment was removed by dredging and taken to a licensed landfill for disposal.
In addition, Great Lakes Restoration Initiative funding went to the Wisconsin Department of Natural Resources and the City of Sheboygan for habitat restoration projects along the river. These projects included shoreline restoration projects at Kiwanis Park, Wildwood Island, and in the area of Taylor Drive and Indiana Avenue, as well as bank stabilization and in-stream habitat projects.
In total, over $80 million has been spent to dredge contaminated sediment and restore habitat in the Sheboygan River AOC. This cleanup work was funded through the Great Lakes Restoration Initiative and by responsible parties through the U.S. EPA’s Superfund Program. All remedial actions identified in the RAP to delist the AOC have been completed.
Ottawa River/Maumee River Area of Concern case study
The Maumee River AOC covers 2,007 km2 and includes the Ottawa River and several tributary creeks. It was expanded in 1992 to include three additional creeks. Beneficial use impairments have included: restrictions on dredging activities, loss of fish and wildlife habitat, restrictions on fish and wildlife consumption, and eutrophication of undesirable algae.
The Ottawa River, a Maumee Bay tributary at Toledo, Ohio, was severely impacted by contaminated sediments. High concentrations of PCBs and metals in the lower river posed unacceptable risks to human and ecological health. Contaminated sediments, especially in the Ottawa River, were a primary reason for designating the Maumee River as an AOC and remediating these contaminated sediments was one of the Maumee River RAP's top priorities.
Historical pollution sources along the Ottawa River included several landfills, industrial facilities, and eight combined sewer overflow points. Initially, controlling contaminants at their source was a top priority. This included capping three landfills, cleaning up five industrial sites, and controlling combined sewer overflows.
U.S. EPA completed a GLLA sediment cleanup in 2011 that involved remediating 192,030 m3 of contaminated sediment from a 9-km stretch of the Ottawa River. These sediments were hydraulically dredged and transported through a pipeline to the nearby Hoffman Road Landfill. U.S. EPA completed this work in partnership with the Ottawa River Group, a consortium of industrial partners, who provided the non-federal cost share for this important GLLA project.
Kinnickinnic River/Milwaukee Estuary Area of Concern case study
The Milwaukee Estuary was designated an AOC in 1985 because of historical discharges that contributed toxic contaminants to the AOC and Lake Michigan. Contaminated sediments and habitat alteration contributed to most of the beneficial use impairments within the AOC.
In 2009, a GLLA project dredged a 0.6-km section of the Kinnickinnic River on the south side of Milwaukee between Kinnickinnic Avenue, the downstream limit, and Becher Street, the upstream limit. This sediment was contaminated primarily with PCBs and PAHs, as a result of expanding urban growth and development, industrial activities, and a lack of effective regulations before the mid–1970s.
In total, 127,680 m3 of contaminated sediment were removed in 2009 at a cost of $22.4 million. The sediment was transported by barge and disposed of in the special cell built at the Milwaukee Area Confined Disposal Facility at Jones Island that is owned by the Port of Milwaukee and operated by the U.S. Army Corps of Engineers. A total of 65% of these funds came from GLLA, with 35% coming from the state bond fund under the Governor’s Growing Milwaukee Initiative. The Kinnickinnic River sediment cleanup was the result of many years of collaboration among U.S. EPA, the U.S. Army Corps of Engineers, Wisconsin Department of Natural Resources, the City and Port of Milwaukee, and local stakeholders, including Business Improvement District #35.
While the problem of contaminated sediments still persists in the Great Lakes, especially in AOCs, measurable progress is being made in the remediation of these contaminated sediments. The rate of sediment remediation activities, removal of beneficial use impairments, and delisting of AOCs has accelerated since the GLLA and Great Lakes Restoration Initiative programs were initiated. However, the job of cleaning up contaminated sediments in Great Lakes AOCs is not complete and sustained efforts under the GLLA, along with state and federal enforcement programs, are required to complete this work and realize the many human health, ecological, and economic benefits of contaminated sediment remediation. Practical sediment remediation lessons include:
Developing and maintaining good working relationships between all project partners is a key to success;
Selecting and sizing of equipment (e.g. dredge) is an important consideration in keeping projects on schedule; and
Placement methods for chemical containment layer are critical to project success.
Completed sediment cleanups have been a springboard for local communities to convert areas that were once a detriment to economic growth into valuable waterfront economic assets (Great Lakes Commission and U.S. EPA, 2011). These communities are literally transforming former toxic “hot spots” into amenities and building a foundation for future growth. For example, the sediment remediation of the Kinnickinnic River in Milwaukee, Wisconsin contributed directly to the creation of a waterfront destinations for businesses, recreation, and tourism.
Continued efforts to remediate contaminated sediments in Great Lakes AOCs can set the stage for completing habitat restoration actions and lead to community revitalization under a “remediation to restoration to revitalization” framework that has provided immense benefits to AOCs. Additionally, initiating and strengthening public-private partnerships has been an important component to the success of the GLLA program. Such partnerships can provide similar benefits to the broader AOC efforts and throughout the larger Great Lakes community.