Contamination in the Floodplains
The 68th Street Dump Site Case Study
by Zoe Kerrich
Photo by Micah Epstein.
Managing land contaminated by hazardous wastes from industrial activities is a major challenge for improving environmental quality in the United States. The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) is one tool the United States Environmental Protection Agency (EPA) uses to remediate contamination at sites of high concern. However, CERCLA does not consider the future hazards of climate change, and many CERCLA sites are located in areas at risk of flooding due to extreme weather events or sea level rise. The 68th Street Dump in Baltimore shows how historic siting choices have resulted in Superfund sites in floodplains or at risk of sea level rise from climate change. This report discusses what current practices exist for remediation of these sites, and the interim protection of surrounding environmental quality. Finally, this report discusses complications of, and environmental justice considerations for, cleanups at high-risk sites, and discusses appropriate future land use planning around Superfund sites in floodplains.
68th Street Dump Case Study
In the Chesapeake Bay Watershed, at the headwaters of the Back River, there are 239 acres of land that have suffered from decades of hazardous material disposal and dumping. This site, the 68th Street Dump, spans land across the municipalities of the city of Baltimore and nearby Rosedale, Maryland. The area is bounded by highways: I-95 to the west and 695 to the east. The land surrounding the dump is primarily industrial in use, with the exception of some residential zoning to the northeast. Multiple types of landfills operated on the site between late 1940s and the late 1970s, including municipal, industrial, and hazardous waste landfills. The headwaters of the Back River are a wetland ecosystem, much of which was filled in during the use of the site for landfill operations.
In 1999, EPA proposed adding the 68th St Dump to the National Priorities List, thereby designating it as a CERCLA (Superfund) site. Hazardous materials from industrial activities dumped at the site include solvents, paints, fly ash, automobile tires, and 55-gallon drums containing heavy metal sludges. The site has experienced uncontrolled fires, nuisance odors, and migration of oil and refuse into local waterways. There are six waterways that pass through the area which flow east, south, and north. Thus, hazardous waste and contamination at the 68th Street Dump have spread offsite via these waterways into the Chesapeake Bay (eastward), and to areas north and south of the site. Testing by EPA of these waterways revealed elevated concentrations of antimony, arsenic, barium, iron, and manganese.
Access to the area was unrestricted prior to remediation activities, and trespassing frequent. With hazardous substance releases and contamination of the sediment, surface water, groundwater, and biological resources (e.g., soil and benthic invertebrates, plants, birds, mammals, and fish), trespassers were likely exposed to and may have transported contaminated materials. Addressing contamination on-site required categorizing the 239 acres of land into seven Management Area(s) (MAs). For all MAs, EPA has proposed venting landfill gas, constructing barriers to prevent trespasser access to the site, implementing institutional controls, and establishing monitoring and maintenance programs. Institutional controls include environmental covenants and zoning restrictions to limit future site uses, such as precluding residential zoning, prohibiting subsurface disturbance, and prohibiting use of groundwater. Three drums potentially containing hazardous materials were removed in the 1980s, but as of 2018 long-term cleanup activities have yet to begin. The remediation methods under consideration include excavation of sediment, soil cover over sediment with other remediation treatments, engineered caps of sediment, and wetland systems. Across the MAs, engineered caps were not selected because of high costs and the necessary conversion of the area landscape from wooded forest to grasslands, which would increase stormwater runoff into the Chesapeake Bay.  Instead, remediation plans include soil cover for three of the MAs, one with an enhanced wetland system, excavation at three of the MAs, and limited action at the seventh MA. Potential future uses for the management areas suggested by EPA include light industrial, solar energy generation, habitat enhancement, and passive or active recreation. 
The 68th Street Dump Site varies in elevation from near mean sea level to greater than 80 feet above mean sea level and is a wetland area connected to the Chesapeake Bay. Some areas of the site will become inundated with even one foot of sea-level rise, and with five feet of sea level rise, more than 25 percent (63 acres) of the site will be inundated.  EPA’s Final Action Record of Decision (ROD) for the site does not discuss potential impacts of climate change hazards, including sea level rise, on contamination pathways. Inundation at the site has the potential to impact both contamination pathways and appropriate future uses of the site after remediation. The site is also under pressures associated with population growth: while the city of Baltimore saw a slight decline in population between 2010 and 2020, the suburbs surrounding it, including Rosedale, continue to see growth in population.
Photo by Zoe Kerrich
Wetlands and Zoning
Wetlands in the United States are a disappearing ecosystem: more than half of the original wetlands in the lower 48 states have been filled in.  Historically, the US has viewed wetlands as unproductive land and damaged or changed the land by draining these landscapes for agricultural uses, using wetland areas as sites for landfills, or draining and filling the land for development.  When cities across the United States began to implement zoning ordinances starting in the 1920s, areas in floodplains were usually zoned for industrial uses, as wetlands were seen as unsanitary and undesirable land for residential uses.  Many of these urban floodplains were residential areas however, with poor and minority groups frequently building housing in these areas because wetlands were often the only areas in the city that had open land with unrestricted access. Industrial zoning of areas disadvantaged communities lived in has resulted in a legacy of environmental injustices; in urban areas poor and minority individuals are far more likely to live near industrial areas and are thus disproportionately exposed to environmental hazards including poor air and drinking water quality. 
As climate change drives sea level rise and increased frequency and intensity of extreme weather events, sites with industrial legacies in or near floodplains are at an increased risk of flooding and even inundation. Flooding of contaminated sites puts surrounding areas at increased risk of exposure to hazards, as floods can transport contaminated water, soil, and sediment across the landscape and deposit these soil media in new locations. Although distributions of population demographics have certainly changed between the 1920s and today, poor and minority populations continue to be more likely to live near Locally Unwanted Land Uses (LULUs) such as industrial sites, including landfills. With many contaminated sites located within floodplains, and disadvantaged communities disproportionately more likely to live near these sites, prioritization of remediating Superfund or other contaminated sites within the floodplain is an environmental justice issue.
The populations living closest to the 68th Street Dump Site are in census tract 4501 in Rosedale, which includes Rosedale Terrace, located immediately east of the site.  Overall, the population in Rosedale has not changed significantly in size over the past decade (from 19,257 in 2010 to 19,961 in 2020), but the population has diversified significantly. In 2000, 75 percent of the population identified as white, while in 2020 the white share of the population decreased to 53 percent.  Additionally, the 68th Street Dump Site is not the only source of potential contamination in the area; the Back River Sewage Treatment Plant is some 2,600 feet downstream of the site at the confluence of Herring Run and Back River, several interstate highways cross over waterways near the site which contribute to roadway stormwater runoff discharge onto the site, and within a one-mile radius of the 68th Street Dump Site there are six sites identified by the Maryland Department of Environment as potential hazardous waste sites. One of the six sites identified by the Maryland Department of Environment is the Kane and Lombard federal Superfund site, approximately 3,000 feet southwest of the 68th Street Dump Site.  The siting of multiple potential sources of contamination in such close proximity to each other and in the floodplain of Herring Run poses significant risks to both local populations and the wetland ecosystem in the area, including nearby sections of the Chesapeake Bay.
Congress passed the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, also known as the Superfund law, in response to the discovery and necessary emergency cleanup of a toxic dumpsite underneath a residential development.  While the Resource Conservation and Recovery Act of 1976 addresses the management and disposal of hazardous wastes, it does not provide a mechanism for remediating contamination of the environment resulting from improper management or disposal of hazardous materials.  Crucially, the Superfund law provides a funding mechanism for financing cleanup and remediation activities. EPA has the authority to recover cleanup costs from parties responsible for contamination, can bill individual states for 10 percent of cleanup costs on private land and 50 percent of costs on public land, and Congress established a tax on chemical and petroleum industries that funds a trust fund for cleanup activities. [13, 14]Not all contaminated sites in the United States are part of the Superfund program; today there are 1,333 sites on the National Priorities List. Contaminated sites on the National Priorities List are sites with significant contamination that require long-term cleanup efforts. 
Nineteen Potentially Responsible Parties (PRPs) signed an agreement with EPA in 2006 to investigate contamination and develop cleanup alternatives at the 68th Street Dump site.  The group of PRPs includes former property owners and businesses that either generated or transported waste to landfills at the site.  EPA added the site to the National Priorities List due to surface water contamination alone, although contamination is also present in the groundwater and soil on-site. 
The 68th Street Dump in Baltimore shows how historic siting choices have resulted in Superfund sites in floodplains or at risk of sea level rise from climate change.
Remediation Practices and Considerations
Addressing contamination can be decades-long process, particularly at larger or more contaminated sites. EPA initially proposed adding the 68th Street Dump Site to the NPL in 1999, and more than two decades later it is unclear if remediation activities have begun. The site was officially listed as a Superfund site in 2003, and the site’s Record of Decisions for Final Action (ROD) was published in September of 2013. Since adding sites to the NPL is an arduous process, many contaminated sites are addressed at the state level or, as in the case of the 68th Street Dump prior to listing, are only addressed on an as needed or emergency basis. EPA estimates that there are more than 450,000 brownfield sites in the US – sites that require some remediation for re-use, but are not immediate threats to human or ecological health. 
For sites that are added to the NPL, EPA assesses contamination types, media, and levels to determine what treatment and cleanup options may be appropriate for a site to develop a proposed plan for site cleanup. Cleanup activities generally contain contamination on-site, via engineered caps or soil cover systems, or remove contamination by excavating or draining contaminated soil and sediment or surface water. Contaminated groundwater is very difficult to clean; remedies usually require continued monitoring of water quality with natural attenuation.  Regardless of clean up methods used, long-term monitoring is required to ensure that remediation was effective. The cleanup at a landfill in New Jersey that EPA placed on the NPL in 1983 was completed in 2013 and continues to be monitored, with required reporting every five years. 
Neither excavation nor on-site management of contamination erase hazardous material from contaminated soil. In the case of excavation, contaminated soil is disposed of in a landfill, with tarps to prevent wind or rain from transporting contaminants. Excavated areas are filled with “clean fill” – soil that is not contaminated. Treating soil may physically remove contaminants via washing, but contaminants washed out of the soil are still hazardous waste that must be disposed of.  The remediation plan for the 68th Street Dump calls for excavation of soil, sediment, and surface water. The plan does not detail how excavated media will be handled.  Across the seven MAs, there is reliance on the natural wetland ecosystem of the area to aid in long-term remediation. EPA anticipates that excavation of contaminated materials in some sections will improve wetland health, allowing for more effective treatment of leachate and groundwater.
The ROD for the 68th Street Dump does not address how sea level rise may impact the remediation methods for the site. While enhancing wetlands in the area can provide long-term remediation services, sea level rise can cause wetlands to migrate upland, and the ecosystem will be lost. Additionally, sea level rise may result in hydrologic connections between contaminated groundwater on-site and groundwater further inland that is not currently connected.  The 68th Street Dump Site is located in the Coastal Plain region of Maryland, where 1.4 million people rely on groundwater in the Coastal Plain.  While the natural flow of groundwater near the 68th Street Dump Site is towards the Chesapeake Bay and away from residential areas, significant groundwater pumping has the potential to alter groundwater flows. In a report from USGS in 1996, authors reported large regional cones of groundwater depression due to heavy groundwater extraction in the area.  As local hydrologic conditions change with sea level rise, current remediation processes may no longer be the best available option for protecting human health and local ecosystems.
Interim Protection Measures
Existing interim protection measures may also be insufficient to protect human health and local ecosystems in the face of sea level rise and extreme weather events. Protection measures prior to remediation may include emergency removal actions and institutional controls. 
Community involvement in decision-making for remediation activities functions both as an information institutional control and ensures that community members are able to provide input into and potentially shape decisions around remediation. For the 68th Street Dump Site, the Community Involvement Plan from 2013 notes that community involvement up to that point had primarily consisted of public meetings and fact sheets distributed to community members. By consistently providing information and updates on work at the site, EPA can discourage trespassing on the contaminated land. While institutional controls such as community involvement and fencing may reduce interim exposure to hazardous wastes by discouraging trespassing, these interim control measures do not address risk of exposure associated with transport of contaminated media during extreme weather events.
In August of 2021, Hurricane Ida brought flooding to the Baltimore area, including Rosedale.  As part of the direct Chesapeake Bay Watershed, Herring Run undoubtedly flooded during this time as well, possibly spreading contaminated media outside of the boundaries of the Superfund site. Local news reports from 2021 note that upstream of the 68th Street Dump, Baltimore County bought out two properties along Herring Run in Towson’s Overbrook neighborhood due to chronic flooding.
Emergency Removal Actions for High-Risk Contaminants
Emergency removal actions, institutional controls, and remediation activities are the suite of tools EPA relies on to address contaminated sites. Emergency removal actions are important to address immediate risk presented by hazardous waste, such as the removal of forty 55-gallon drums from the 68th Street Dump site following a fire on site in 1985.  Yet similar to remediation activities, contaminated materials must be addressed even once removed from the site. The Resource Conservation and Recovery Act (RCRA) stipulates five ways to dispose of toxic waste: burial, deep-well injection, incineration, fly-age storage, and treatment and storage in liquid form.  No disposal method eliminates risk of future exposure to hazardous waste: landfills can leak, deep-well injection can contaminate aquifers, incineration can release toxins into the air, fly ash can contaminate groundwater if it interacts with stormwater runoff, and containers of liquids can corrode and leak over time.  Just as the initial siting of land uses that rely on hazardous materials is an environmental justice issue, so too is the disposal of hazardous wastes from contaminated sites.
There are 11 RCRA sites in Maryland that accept off-site hazardous waste.  The two closest to the 68th Street Dump are both in the city of Baltimore; a city with a poverty rate nearly twice the national average (Baltimore: 20%; US overall: 11.4%), and a majority Black population (62%, compared to 13.4% for the US overall). EPA anticipates that remediation activity at the 68 Street Dump site will begin in 2023; from available documentation there is no information on where excavated contaminated soil, or other hazardous wastes present on-site will be transported to for disposal. But it is likely that one of these two landfills will be the selected location; proximity is usually a driving factor in deciding where to transport contaminated materials, as the further the transportation distance, the more opportunity there is for accidental dispersal of contaminated material. Contaminated soil is usually transported in a truck, with a tarp over the soil to reduce dust and associated dispersal of contaminated media. Poor and minority communities are disproportionately likely to live in places with exposure to environmental contamination; even as state and federal agencies work to clean up historically contaminated sites, this does not necessarily reduce the disproportionate impact. For sites like the 68th Street Dump Site, the process for deciding how to clean up the site is complex; leaving contamination on-site increases risk of local dispersal of contamination during flooding events and long-term contamination of groundwater resources due to sea level rise, while off-site management of hazardous media may simply place the burden of risk on other communities instead.
Future Remediation and Land Use Planning
There are no clear-cut solutions for addressing legacy contamination at the 68th Street Dump Site, particularly in areas at risk of flooding and other climate change-driven disruptions. The current remediation plan for the 68th Street Dump relies on natural remediation from the wetland ecosystem of the area; as the sea rises this ecosystem will no longer be able to provide this ecosystem service. Managing contamination on-site in the future may require installing flood protection measures such as sea walls or earthen berms, such as those installed at the American Cyanamid Superfund site in New Jersey. This site flooded during Hurricane Irene in 2011 prior to installation of flood protection measures, but did not flood during Hurricane Ida in 2021.  Similar to the 68th Street Dump Site, the American Cyanamid Superfund site is located only 700 feet from the Raritan River. Other aspects of the cleanup plan are significantly different, however.  The American Cyanamid Superfund site cleanup relies on binding contaminated soil and sediment by introducing additives to solidify the material, and several areas of the site will be capped engineered materials.  These approaches were not considered at the 68th Street Dump Site due to the negative ecological impacts. 
Future uses of the 68th Street Dump Site suggested by EPA, once remediation activities are complete, include light industrial, solar energy generation, open space, habitat enhancement, and recreation.  In the context of the most recent sea level rise projections, some of these uses are likely to no longer appropriate. Additionally, the site has unique ecological value as one of the few un-urbanized parcels of land in the Baltimore area. The site reduces stormwater runoff into Back River and the Chesapeake Bay, so any use that reduces vegetation and topographic complexity would damage the larger ecosystem. However, remediation activity and future land use planning for the site that does not factor in future flooding risk puts nearby communities and vital ecosystems at risk of contamination. An increased focus on wetland enhancement on-site, and reductions in impervious surface coverage in the surrounding wetland could potentially reduce the flood extents and thus exposure and spread of contaminants.
For sites like the American Cyanamid Superfund Site, engineered caps and soil solidification and stabilization may be appropriate if ecosystem services have already been lost. However, for sites like the 68th Street Dump, enhancing ecosystem services with a plan to support inland migration of wetlands can assist in environmental remediation of contaminants and manage stormwater runoff. On-site management or removal of contaminated materials should also consider risk to human and ecological health associated with sea level rise, flooding, or other extreme weather events.
About the Author: Zoe Kerrich
Zoe Kerrich is a second-year student in the City Planning Department of the Stuart Weitzman School of Design at the University of Pennsylvania, focusing on various intersections of water and health. In her free time, Zoe loves to weave, and is looking forward to having even more free time post-graduation to focus on lost wax metal casting.
1 ROD, 46.
2 ROD, 19.
3 Community involvement plan.
4 Daniels, 2014, p. 343.
6 Moga, 2020.
7 Center for Science and Democracy, 2020.
8 Environmental Resources Management, Inc. 2013.
9 United States Census Bureau, 2000 and 2020 decennial
10 Environmental Resources Management, Inc. 2013.
11 Daniels, 2014, p. 252.
12 Ibid. p. 251.
13 Ibid. p. 253.
14 USEPA, CERCLA overview.
15 There are three ways a site may become eligible for the National Priorities List: (1) a site may receive a Hazard Ranking System score of greater than 28.5; (2) a state or territory may designate one site annually for listing; (3) the Agency for Toxic Substances and Disease Registry may issue a public health advisory along with other requirements. USPEA, NPL site listing process.
16 The Superfund law has a strict liability provision, which makes all current or previous owners, or site users potentially liable for cleanup costs, regardless of whether they contributed to the contamination activity.
17 ROD, 2013, p. 5.
18 USEPA, HRS Documentation Record: 68th Street Dump.
19 USEPA, Brownfields Program Overview:
20 USEPA, Guidance for Groundwater Cleanups.
21 USAEPA, Brick Township Landfill.
22 Chemtech International, Dealing with Contaminated Soils.
23 ROD, 2013, p. 52.
24 USGS, 2020.
25 Maryland Geological Survey, “Groundwater.”
26 Fleck and Vroblesky, 1996.
27 USEPA, Citizen’s Guide to Understanding Institutional
28 Cardin, 2021.
29 Hayes, 2021.
30 ROD, 2013, p. 7.
31 Daniels, 2014, p. 245.
33 RCRAInfo Database.
34 USEPA, A Citizen’s Guide to Excavation of Contaminated Soil, 2012.
35 USEPA, American Cyanamid Superfund Site, 2021.
37 USEPA, American Cyanamid Co Bridgewater, NJ.
38 ROD, 2013. Alternatives.
39 ROD, 2013, p. 19.