NOAA's Response and Restoration Blog

An inside look at the science of cleaning up and fixing the mess of marine pollution


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In Oregon, an Innovative Approach to Building Riverfront Property for Fish and Wildlife

This is a post by Robert Neely of NOAA’s Office of Response Restoration.

Something interesting is happening on the southern tip of Sauvie Island, located on Oregon’s Willamette River, a few miles downstream from the heart of Portland. Construction is once again underway along the river’s edge in an urban area where riverfront property typically is prized as a location for luxury housing, industrial activities, and maritime commerce. But this time, something is different.

This project will not produce a waterfront condominium complex, industrial facility, or marina. And as much as it may look like a typical construction project today, the results of all this activity will look quite different from much of what currently exists along the shores of the lower Willamette River from Portland to the Columbia River.

Indeed, when the dust settles, the site will be transformed into a home and resting place for non-human residents and visitors. Of course, I’m not referring to alien life forms, but rather to the fish, birds, mammals, and other organisms that have existed in and around the Willamette River since long before humans set up home and shop here. Yet in the last century, humans have substantially altered the river and surrounding lands, and high-quality habitat is now a scarce commodity for many stressed critters that require it for their survival.

On the site of a former lumber mill, the Alder Creek Restoration Project is the first habitat restoration project [PDF] that will be implemented specifically to benefit fish and wildlife affected by contamination in the Portland Harbor Superfund Site. The project, managed by a habitat development company called Wildlands, will provide habitat for salmon, lamprey, mink, bald eagle, osprey, and other native fish and wildlife living in Portland Harbor.

Mink at a river's edge.

The Alder Creek Restoration Project will benefit Chinook salmon, mink, and other fish and wildlife living in Portland Harbor. (Roy W. Lowe)

Habitat will be restored by removing buildings and fill from the floodplain, reshaping the riverbanks, and planting native trees and shrubs. The project will create shallow water habitat to provide resting and feeding areas for young salmon and lamprey and foraging for birds. In addition, the construction at Alder Creek will restore beaches and wetlands to provide access to water and food for mink and forests to provide shelter and nesting opportunities for native birds.

Driving this project is a Natural Resource Damage Assessment conducted by the Portland Harbor Natural Resource Trustee Council to quantify natural resource losses resulting from industrial contamination of the river with the toxic compounds PCBs, the pesticide DDT, oil compounds known as PAHs, and other hazardous substances. The services, or benefits from nature, provided by the Alder Creek Restoration Project—such as healthy habitat, clean water, and cultural value—will help make up for the natural resources that were lost over time because of contamination.

Young Chinook salmon on river bottom.

Fish and wildlife species targeted for restoration include salmon (such as the juvenile Chinook salmon pictured here), lamprey, sturgeon, bald eagle, osprey, spotted sandpiper, and mink. (U.S. Fish and Wildlife Service)

Wildlands purchased the land in order to create and implement an early restoration project. This “up-front” approach to restoration allows for earlier implementation of projects that provide restored habitat to injured species sooner, placing those species on a trajectory toward recovery. The service credits—ecological and otherwise—that will be generated by this new habitat will be available for purchase by parties that have liability for the environmental and cultural losses calculated in the damage assessment.

Thus when a party reaches an agreement with the Trustee Council regarding the amount of their liability, they can resolve it by purchasing restoration credits from Wildlands. And Wildlands, as the seller of restoration credits, recoups the financial investment it made to build the project. Finally, and most importantly, a substantial piece of land with tremendous potential value for the fish, birds, and other wildlife of the lower Willamette River has been locked in as high-quality habitat and thus protected from future development for other, less ecologically friendly purposes.

Robert NeelyRobert Neely is an environmental scientist with the National Oceanic and Atmospheric Administration’s Office of Response and Restoration. He has experience in ocean and coastal management, brownfields revitalization, Ecological Risk Assessment, and Natural Resource Damage Assessment. He started with NOAA in 1998 and has worked for the agency in Charleston, South Carolina; Washington, DC; New Bedford, Massachusetts; and Seattle, Washington, where he lives with his wife and daughter. He’s been working with his co-trustees at Portland Harbor since 2005.


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On the Chesapeake Bay, Overcoming the Unique Challenges of Bringing Restoration to Polluted Military Sites

Transformations are taking place at more than 10 government facilities, mostly owned by the Department of Defense, across the Chesapeake Bay and its tributaries. These properties typically include large, relatively undisturbed natural areas, which often serve as key habitats for endangered fish, birds, and wildlife. Yet the same federal facilities also have become Superfund sites, slated for cleanup under CERCLA, with pollution at levels which threaten the health of humans and the environment.

Heavy equipment clearing a former landfill for restoration.

Naval Amphibious Base Little Creek, a major base for the Navy’s Atlantic fleet, is one of the facilities that was slate for cleanup on the Chesapeake Bay. Here, heavy equipment prepare a former landfill for restoration post-cleanup in 2006. (U.S. Navy)

Yet in spite of some unique challenges, these areas are being cleaned up and restored to become healthy places for all once more. Success has stemmed largely from two critical pieces of the process: collaborating closely among numerous government agencies and incorporating restoration into the process as early and often as possible.

According to Paula Gilbertson of the U.S. Navy, “The close partnership among the many federal and state agencies involved has provided a framework for success. Great things can happen when people work together toward a common goal.”

Moving Past the Past

Past activities leading to pollution at U.S. Army, Air Force, and Navy sites on Chesapeake Bay were many and varied, and included: incineration, landfilling, ship and airplane repair and maintenance, military testing, and pesticide and munitions disposal. As a result, beginning in the 1980s, entire facilities along the bay became Superfund sites and listed for priority cleanup.

Typically during the Superfund process, the party responsible for polluting has to work with the U.S. Environmental Protection Agency (EPA), which leads the cleanup, and other state and federal agencies—known as trustees—which represent affected public lands and waters.

A landfill on the Little Creek naval base before cleanup.

A landfill on the Little Creek naval base before cleanup in 2006. (U.S. Navy)

But in these cases, the Department of Defense has to play multiple roles: trustee of natural resources on the property, entity responsible for contamination, and lead cleanup agency. In addition, the EPA still oversees the effectiveness of the Superfund cleanup, and the military branches at each site still have to coordinate with the other trustees: NOAA, the U.S. Fish and Wildlife Service, and state agencies.

NOAA and the Fish and Wildlife Service also are part of a special technical group run by the EPA (the Biological Technical Assistance Group, or BTAG), which coordinates trustee participation and offers scientific review throughout the ecological risk assessment and cleanup process at each site.

According to Bruce Pluta, coordinator of the EPA BTAG, “The collaborative efforts of the EPA Project Team, including the BTAG, and our partners at the Department of Defense have resulted in model projects which integrate remediation and ecological restoration.”

Working Together for the Future

What does not change during this process is that the trustees are working to protect and restore the “trust resources,” including lands, waters, birds, fish, and wildlife affected by contamination coming from these military sites. This can include natural areas adjacent to the sites and the animals that could migrate onto the federal properties, such as striped bass, herring, blue crabs, eagles, and herons.

Other important differences exist governing how all these government entities work together in the Superfund cleanup process. For example, NOAA often works to evaluate ecological risks and determine environmental injuries resulting from hazardous material releases at Superfund sites. Then we implement restoration projects to compensate for the injuries to coastal and marine natural resources and the benefits they provide to the public. This is the Natural Resource Damage Assessment process. NOAA seeks legal damages (payment) or works with those responsible for the pollution through cooperative agreements to restore, replace, or acquire the equivalent natural resources.

Restored wetlands.

A site transformed: Immediately after completion of cleanup and restoration activities at a landfill on the Little Creek naval base on the Chesapeake Bay. (U.S. Environmental Protection Agency)

As federal trustees, we are significantly limited in our ability to conduct a formal damage assessment against a fellow federal agency doing cleanup because we are both trustees of the affected natural resources. However, all federal and state trustees can work together with EPA to protect the lands, waters, and living things during cleanup, maximize the potential for restoration at each site, and develop measures to ensure both environmental recovery and resilience.

“By considering restoration early in the process and getting input from natural resource managers, many simple, common sense measures are being incorporated that benefit ecosystems, reduce overall costs, and improve the effectiveness of the cleanup,” says Simeon Hahn of NOAA.

Overcoming Challenges

Having so many government agencies involved in overlapping but distinct roles requires a great deal of collaboration and communication. This became clear early in the process if each case were to achieve multiple objectives:

  • Cleaning up the military sites and returning the lands and waters to productive uses.
  • Performing cleanups using environmentally friendly strategies to remove, recycle, and reuse materials while also addressing climate resiliency.
  • Protecting and restoring natural resources.
  • Accomplishing everything within a reasonable budget and timeframe.

Despite the many challenges, the process of cleaning up and restoring these contaminated military facilities has been going well. EPA, the Department of Defense, and fellow trustees have collaborated to protect and restore affected natural resources while also helping adapt these areas to the threats and impacts of climate change. By integrating restoration into cleanup planning early and often, we have made significant progress toward a healthier Chesapeake Bay—at lower costs and in less time.

Map of hazardous waste sites on federal properties in the Chesapeake Bay area.

Hazardous waste sites on federal properties in the Chesapeake Bay area. (NOAA)

Over the coming months, we will be sharing more about these successes here on the blog. We will recount the removal and recycling of thousands of tons of concrete; the restoration of hundreds of acres of wetlands, shorelines, creeks, and forested areas; and the revitalization of numerous acres of land contributing to benefits such as natural defenses for coastal communities. Stay tuned!


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How Much do Coastal Ecosystems Protect People from Storms and What is It Worth?

Sand dunes with grass.

Sand dunes along the New Jersey shore. (NOAA)

 This post was written by the Office of Response and Restoration’s Meg Imholt and is based on research done during the summer of 2014 by OR&R intern, Emory Wellman.

Nearly a year ago, one lawsuit spurred the question–how much do coastal ecosystems protect people from storms and what is that worth?  It’s a question NOAA scientists and economists are working to answer.

At NOAA, our job is to protect our coasts, but often, coastal ecosystems are the ones protecting us. When a severe storm hits, wetlands, sand dunes, reefs, and other coastal ecosystems can slow waves down, reducing their height and intensity, and prevent erosion.  That means less storm surge, more stable shorelines, and more resilient coastal communities.

When the coastal Borough of Harvey Cedars, New Jersey, replenished beaches with sand dunes to offer this ecosystem service, a New Jersey couple, the Karans, sued on the grounds that the newly placed dunes obstructed the ocean view from their home. Initially, the court barred the jury from considering storm protection benefits from the dunes in their decision. The jury awarded the Karans $375,000, but New Jersey Supreme Court overturned the ruling. The jury should consider storm protection benefits, according to the Supreme Court, and when it did, the Karan’s settlement dropped to $1.

Cases like this one spur a lot of questions for both science and the courts.

NOAA has been supporting ecosystem services in court for decades through Natural Resource Damage Assessments (NRDA), but putting a price tag on ecosystem services isn’t easy. Instead, NOAA often determines how ecosystem services were hurt and what it will take to replace them.  Following a spill or chemical release, NOAA is one of a number of mandated state and federal natural resource trustees that assess if and how ecosystem services were injured and typically focuses on habitat and recreation. That assessment is then used to determine how much restoration the responsible party must provide to compensate for the injury.

Destroyed homes along the coast.

At the end of October 2012, Hurricane Sandy sped toward the East Coast, eventually sweeping waves of oil, hazardous chemicals, and debris into the coastal waters of New Jersey, New York, and Connecticut. (U.S. Air Force)

Determining exactly how much storm protection may have been lost is another challenge. We know that already; there are a variety of estimates showing how much coastal ecosystems reduce a storm’s impact. Still, the science of storm protection is complicated. For example, an ecosystem’s type, location, topography, and local tides all impact its ability to protect us from storms. So, determining how much storm protection services were lost, who they benefited, and what type of restoration could compensate depends on all of those factors too.

Ultimately, the decision on how to assess storm protection benefits may be up to the courts.  The next case like Borough of Harvey Cedars v. Karan may provide some clues, but until then, we’ll keep working on the science.


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Buoys Serve as Latest Gardening Tool for Restoring Eelgrass in San Francisco Bay

Bright red buoys floating on a bay.

“Seed buoys” are dotting the waters of San Francisco Bay. Below the water, they are attached to mesh bags filled with shoots of eelgrass, which spread seeds that will eventually sprout and restore habitat on the bay’s bottom. (NOAA)

Many of us likely have spent some time planting seeds in our yards to grow vegetables or flowers. But how do scientists plant seeds to help restore plants in our bays and coastal waters? If you look out on the waters of San Francisco Bay right now, you can see the answer.

Floating on the surface of the bay is a series of “seed buoys.” Each buoy is connected to a mesh bag containing shoots of the underwater plant eelgrass (Zostera marina). These shoots, which are flowering, were harvested by biologists and will soon be releasing ripening seeds. These buoys will move with the tides, distributing seeds that, by next spring, will develop into new eelgrass seedlings on the bay bottom. The seed buoy is a relatively easy, low-tech way of growing this underwater grass. The traditional method of planting eelgrass—by hand in the bay’s floor using scuba divers—can be dangerous, expensive, and labor intensive.

Mesh bags holding flowering eelgrass plants.

Anchored to various locations on the sea floor, seed buoys perform like flowering eelgrass plants, dispersing seeds as the water current moves these mesh bags. Buoys are placed where underwater soil conditions are optimal for the seeds to germinate into young plants. (NOAA)

By seeding and transplanting eelgrass in this area where none currently exists, we hope to create vibrant eelgrass beds that provide cover and food for fish, juvenile Dungeness crabs, and birds. Eelgrass beds provide important habitat in California’s San Francisco Bay, serving as nurseries for young fish and foraging areas for many species of fish, invertebrates, and birds. They also improve water quality by reducing turbidity, or cloudiness, of the water.

This work is part of a restoration project which has the ultimate goal of compensating for past oil spill impacts in San Francisco Bay as a result of the 2007 M/V Cosco Busan oil spill. It aims to create 70 new acres of eelgrass habitat at several sites throughout San Francisco Bay over nine years. This project is funded by the legal settlement resulting from the cargo ship Cosco Busan striking one of the towers of the San Francisco-Oakland Bay Bridge and releasing 53,000 gallons of heavy oil into the surrounding waters.

A result of the work of the Cosco Busan Oil Spill Trustee Council, the eelgrass restoration project also is carried out in cooperation with San Francisco State University and Merkel and Associates, Inc.

For more information, you can read about:


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With Lobster Poacher Caught, NOAA Fishes out Illegal Traps from Florida Keys National Marine Sanctuary

This is a post by Katie Wagner of the Office of Response and Restoration’s Assessment and Restoration Division.

On June 26, 2014, metal sheets, cinder blocks, and pieces of lumber began rising to the ocean’s surface in the Florida Keys National Marine Sanctuary. This unusual activity marked the beginning of a project to remove materials used as illegal lobster fishing devices called “casitas” from sanctuary waters. Over the course of two months, the NOAA-led restoration team plans to visit 297 locations to recover and destroy an estimated 300 casitas.

NOAA’s Restoration Center is leading the project with the help of two contractors, Tetra Tech and Adventure Environmental, Inc. The removal effort is part of a criminal case against a commercial diver who for years used casitas to poach spiny lobsters from sanctuary waters. An organized industry, the illegal use of casitas to catch lobsters in the Florida Keys not only impacts the commercial lobster fishery but also injures seafloor habitat and marine life.

Casitas—Spanish for “little houses”—do not resemble traditional spiny lobster traps made of wooden slats and frames. “Casitas look like six-inch-high coffee tables and can be made of various materials,” explains NOAA marine habitat restoration specialist Sean Meehan, who is overseeing the removal effort.

The legs of the casitas can be made of treated lumber, parking blocks, or cinder blocks. Their roofs often are made of corrugated tin, plastic, quarter-inch steel, cement, dumpster walls, or other panel-like structures.

Poachers place casitas on the seafloor to attract spiny lobsters to a known location, where divers can return to quite the illegal catch.

A spiny lobster in a casita on the seafloor.

A spiny lobster in a casita. (NOAA)

“Casitas speak to the ecology and behavior of these lobsters,” says Meehan. “Lobsters feed at night and look for places to hide during the day. They are gregarious and like to assemble in groups under these structures.” When the lobsters are grouped under these casitas, divers can poach as many as 1,500 in one day, exceeding the daily catch limit of 250.

In addition to providing an unfair advantage to the few criminal divers using this method, the illegal use of casitas can harm the seafloor environment. A Natural Resource Damage Assessment, led by NOAA’s Restoration Center in 2008, concluded that the casitas injured seagrass and hard bottom areas, where marine life such as corals and sponges made their home. The structures can smother corals, sea fans, sponges, and seagrass, as well as the habitat that supports spiny lobster, fish, and other bottom-dwelling creatures.

Casitas are also considered marine debris and potentially can harm other habitats and organisms. When left on the ocean bottom, casitas can cause damage to a wider area when strong currents and storms move them across the seafloor, scraping across seagrass and smothering marine life.

“We know these casitas, as they are currently being built, move during storm events and also can be moved by divers to new areas,” says Meehan. However, simply removing the casitas will allow the seafloor to recover and support the many marine species in the sanctuary.

There are an estimated 1,500 casitas in Florida Keys National Marine Sanctuary waters, only a portion of which will be removed in the current effort. In this case, a judge ordered the convicted diver to sell two of his residences to cover the cost of removing hundreds of casitas from the sanctuary.

To identify the locations of the casitas, NOAA’s Hydrographic Systems and Technology Program partnered with the Restoration Center and the Florida Keys National Marine Sanctuary. In a coordinated effort, the NOAA team used Autonomous Underwater Vehicles (underwater robots) to conduct side scan sonar surveys, creating a picture of the sanctuary’s seafloor. The team also had help finding casitas from a GPS device confiscated from the convicted fisherman who placed them in the sanctuary.

After the casitas have been located, divers remove them by fastening each part of a casita’s structure to a rope and pulley mechanism or an inflatable lift bag used to float the materials to the surface. Surface crews then haul them out of the water and transport them to shore where they can be recycled or disposed.

For more information about the program behind this restoration effort, visit NOAA’s Damage Assessment, Remediation, and Restoration Program.

Katie Wagner.Katie Wagner is a communications specialist in the Assessment and Restoration Division of NOAA’s Office of Response and Restoration. Her work raises the visibility of NOAA’s effort to protect and restore coastal and marine resources following oil spills, releases of hazardous substances, and vessel groundings.


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Two Unlikely Neighbors, Orphans and Industry, Share a Past Along the Delaware River

Sign in a grassy field, in front of an old brick building.

An EPA sign marking the Metal Bank Superfund Site stands near the old St. Vincent’s Orphanage building. (EPA)

When NOAA environmental scientist Alyce Fritz talks about her first visit to the Metal Bank Superfund Site back in 1986, she always mentions the orphanage next door. St. Vincent’s Orphans Asylum, as it was named when it was opened by the Catholic Archdiocese of Philadelphia in 1857, is separated from the Metal Bank site by a stormwater outfall that drains into the Delaware River just north of the former orphanage.

The Metal Bank Superfund Site and St. Vincent’s are located several miles north of the center of Philadelphia, Pennsylvania, on the banks of the Delaware River in an industrial district that is part of the historic Tacony neighborhood. Located on 29 acres along the river, St. Vincent’s looks like a beautiful old park. What Fritz remembers clearly on that first visit was the children’s playground equipment placed near the river’s edge.

Large brick building with St. Vincint's over the door.

St. Vincent’s, as it appears today on the Delaware River in the Tacony neighborhood of Philadelphia.

On the adjacent 10 acre Metal Bank site, a company called Metal Bank of America, Inc., owned and operated a salvage facility where scrap metal and electric transformers were recycled for over 60 years. Part of the recycling process used by Metal Bank of America, Inc. involved draining oil—loaded with toxic compounds including PCBs—from the used transformers to reclaim copper parts. PCBs are considered a probable cause of cancer in humans and are harmful to clams and fish found in the mudflats and river next to the site.

In the 1970s the U.S. Coast Guard discovered oil releases in the Delaware River and traced them back to the site. Throughout the 1980s, the Metal Bank site’s owners used an oil recovery system to clear the groundwater of PCB-laced oil. However, oil continued to seep from an underground tank at the site. As a result, PCBs and other hazardous substances were left in the soil, groundwater, and river bed sediments at the Metal Bank site and adjacent to St. Vincent’s.

In 1983 the Metal Bank site was placed on the National Priorities List (the Superfund program) and slated for federal cleanup. During the course of the federal cleanup process, various parties were identified as being liable for the contamination at the site, including a number of utility companies that transported their used electrical transformers to the Metal Bank site for disposal or otherwise arranged to dispose of their used electrical transformers at the Metal Bank site.

Federal and local agencies collaborated on a design for cleanup of multiple contaminants of concern at the Metal Bank site. Found in the soil, sediment, groundwater, and surface water, these contaminants included but were not limited to:

  • PCBs.
  • polynuclear aromatic hydrocarbons (a toxic component of oil).
  • semi-volatile organic compounds.
  • pesticides.
  • metals.

The cleanup, which began in 2008, included excavating soils and river sediments contaminated with PCBs, capping some areas of river sediment, installing a retaining wall near the river, and removing an old transformer oil storage tank. Most of this work was completed in 2010.

Panorama of Metal Bank Superfund Site from the top of steps by the river to the mudflats in 1991. The view is looking south on the Delaware River past St. Vincent’s property. (NOAA) A view of the outflow where water runs into the Delaware River to the south of the Metal Bank site in 2013. (NOAA) A riprap sampling station near an oil slick in 1993 in front of the Metal Bank site. (NOAA) A view of the Delaware River across the mudflats on the Metal Bank Site. (EPA)

Panorama of Metal Bank Superfund Site from the top of steps by the river to the mudflats in 1991. The view is looking south on the Delaware River past St. Vincent’s property. (NOAA) A view of the outflow where water runs into the Delaware River to the south of the Metal Bank site in 2013. (NOAA) A riprap sampling station near an oil slick in 1993 in front of the Metal Bank site. (NOAA) A view of the Delaware River across the mudflats on the Metal Bank Site. (EPA)

As part of the required 5-year review period, monitoring of the Metal Bank site continues. This is to ensure the cleanup is still protecting human health and the environment, including endangered Atlantic Sturgeon and Shortnose Sturgeon. Through successful coordination among the EPA, other federal and state agencies, and some of the potentially responsible parties (PRPs) during the Superfund process, the cleanup has reduced the threat to natural resources in the river and enhanced the recovery of the habitat along the site and St. Vincent’s property.

Over the years, the role of St. Vincent’s has evolved too, from serving as a long-term home for orphans toward one of providing short-term shelter and care to abused and neglected children. Prior to the early 1990s, children who came to St. Vincent’s spent a significant part of their childhood as residents of the institution. In a 1992 article in the Philadelphia Daily News, Sister Kathleen Reilly explained that the children currently cared for by St. Vincent’s range in age from two to 12 years of age and are placed at the home temporarily through an arrangement between the City of Philadelphia Department of Human Services and Catholic Social Services. Today St. Vincent’s serves young people mostly through day programs. One thing hasn’t changed though—the lush grounds along the river are still beautiful.

Playground swings at St. Vincent's. Statue of St. Vincent with a child in front of large brick building. Elaborate locked iron gate with a cross. Pavilion with trees and river view.

From top left: A recent photo of part of the play area behind St. Vincent’s on the grounds facing the Delaware River. (NOAA) An old photo of a statue in front of St. Vincent’s Orphan Asylum, as it was originally named. (U.S. Library of Congress) The main building of the historic institution in Northeast Philadelphia that first opened its gates in 1857 as St. Vincent’s Orphans Asylum. Photo was taken in 2013. (NOAA) An old photo of a pavilion in the recreational area behind St. Vincent’s main building. The Delaware River and playground equipment is visible in the background. (U.S. Library of Congress)

The federal and state co-trustees for the ongoing Natural Resource Damage Assessment at the Metal Bank site include NOAA’s Damage Assessment, Remediation, and Restoration Program; the U.S. Fish and Wildlife Service; and multiple Pennsylvania state agencies. Collectively, the trustees are working together to further engage with the potentially responsible parties and build upon what has been accomplished at the site by the cleanup.

The trustees have invited the potentially responsible parties to join them in a cooperative effort to improve habitat for the injured natural resources (such as habitat along the river and wetlands) that support the clams, fish, and birds using the Delaware River. In addition, there is the potential for a trail to be routed through the property to a scenic view of St. Vincent’s and the river (an area which is now safe for recreational use). The trustees hope that the natural resources at the Metal Bank site can evolve to become a vibrant part of the historic Tacony neighborhood once again too.


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As Oil Sands Production Rises, What Should We Expect at Diluted Bitumen (Dilbit) Spills?

Pipeline dug up for an oil spill cleanup next to a creek.

This area is where the Enbridge pipeline leaked nearly a million gallons of diluted bitumen (dilbit), a tar sands oil product, into wetlands, Talmadge Creek, and roughly 40 miles of Michigan’s Kalamazoo River in 2010. (U.S. Environmental Protection Agency)

I’ve seen a lot of firsts in the past four years.

During that time, I have been investigating the environmental impacts, through the Natural Resource Damage Assessment process, of the Enbridge pipeline spill in Michigan. In late summer of 2010, a break in an underground pipeline spilled approximately 1 million gallons of diluted bitumen into a wetland, a creek, and the Kalamazoo River. Diluted bitumen (“dilbit”) is thick, heavy crude oil from the Alberta tar sands (also known as oil sands), which is mixed with a thinner type of oil (the diluent) to allow it to flow through a pipeline.

A Whole New Experience

This was my first and NOAA’s first major experience with damage assessment for a dilbit spill, and was also a first for nearly everyone working on the cleanup and damage assessment. Dilbit production and shipping is increasing. As a result, NOAA and our colleagues in the field of spill response and damage assessment are interested in learning more about dilbit:

  • How does it behave when spilled into rivers or the ocean?
  • What kinds of effects does it have on animals, plants, and habitats?
  • Is it similar to other types of oil we’re more familiar with, or does it have unique properties?

While it’s just one case study, the Enbridge oil spill can help us answer some of those questions. My NOAA colleague Robert Haddad and I recently presented a scientific paper on this case study at Environment Canada’s Arctic and Marine Oil Spill Program conference.

In addition, the Canadian government and oil pipeline industry researchers Witt O’Brien’s, Polaris, and Western Canada Marine Response Corporation [PDF] and SL Ross [PDF] have been studying dilbit behavior as background research related to several proposed dilbit pipeline projects in the United States and Canada. Those experiments, along with the Enbridge spill case study, currently make up the state of the science on dilbit behavior and ecological impacts.

How Is Diluted Bitumen Different from Other Heavy Oils?

Dilbit is in the range of other dense, heavy oils, with a density of 920 to 940 kg/m3, which is close to the density of freshwater (1,000 kg/m3). (In general when something is denser than water, it will sink. If it is less dense, it will float.) Many experts have analyzed the behavior of heavy oils in the environment and observed that if oil sinks below the surface of the water, it becomes much harder to detect and recover. One example of how difficult this can be comes from a barge spill in the Gulf of Mexico, which left thick oil coating the bottom of the ocean.

What makes dilbit different from many other heavy oils, though, is that it includes diluent. Dilbit is composed of about 70 percent bitumen, consisting of very large, heavy molecules, and 30 percent diluent, consisting of very small, light molecules, which can evaporate much more easily than heavy ones. Other heavy oils typically have almost no light components at all. Therefore, we would expect evaporation to occur differently for dilbit compared to other heavy oils.

Environment Canada confirmed this to be the case. About four to five times as much of the dilbits evaporated compared to intermediate fuel oil (a heavy oil with no diluent), and the evaporation occurred much faster for dilbit than for intermediate fuel oil in their study. Evaporation transports toxic components of the dilbit into the air, creating a short-term exposure hazard for spill responders and assessment scientists at the site of the spill, which was the case at the 2010 Enbridge spill.

Graph of evaporation rates over time of two diluted bitumen oils and another heavy oil.

An Environment Canada study found that two types of diluted bitumen (dilbits), Access Western Blend (AWB) and Cold Lake Blend (CLB), evaporated more quickly and to a greater extent than intermediate fuel oil (IFO). The two dilbits are shown on the left and the conventional heavy oil, IFO, on the right. (Environment Canada)

Since the light molecules evaporate after dilbit spills, the leftover residue is even denser than what was spilled initially. Environment Canada, Witt O’Brien’s/Polaris/WCMRC, and SL Ross measured the increase in dilbit density over time as it weathered, finding dilbit density increased over time and eventually reached approximately the same density as freshwater.

These studies also found most of the increase in density takes place in the first day or two. What this tells us is that the early hours and days of a dilbit spill are extremely important, and there is only a short window of time before the oil becomes heavier and may become harder to clean up as it sinks below the water surface.

Unfortunately, there can be substantial confusion in the early hours and days of a spill. Was the spilled material dilbit or conventional heavy crude oil? Universal definitions do not exist for these oil product categories. Different entities sometimes categorize the same products differently. Because of these discrepancies, spill responders and scientists evaluating environmental impacts may get conflicting or hard-to-interpret information in the first few days following a spill.

Lessons from the Enbridge Oil Spill

Initially at the Enbridge oil spill, responders used traditional methods to clean up oil floating on the river’s surface, such as booms, skimmers, and vacuum equipment (see statistics on recovered oil in EPA’s Situation Reports [PDF]).

After responders discovered the dilbit had sunk to the sediment at the river’s bottom, they developed a variety of tactics to collect the oil: spraying the sediments with water, dragging chains through the sediments, agitating sediments by hand with a rake, and driving back and forth with a tracked vehicle to stir up the sediments and release oil trapped in the mud.

These tactics resulted in submerged oil working its way back up to the water surface, where it could then be collected using sorbent materials to mop up the oily sheen.

While these tactics removed some oil from the environment, they might also cause collateral damage, so the Natural Resource Damage Assessment trustees assessed impacts from the cleanup tactics as well as from the oil itself. This case is still ongoing, and trustees’ assessment of those impacts will be described in a Damage Assessment and Restoration Plan after the assessment is complete.

A hand holds a crushed mussel.

A freshwater mussel found crushed in an area of the Kalamazoo River with heavy cleanup traffic following the 2010 Enbridge oil spill. (Enbridge Natural Resource Damage Assessment Trustee Council)

For now, we can learn from the Enbridge spill and help predict some potential environmental impacts of future dilbit spills. We can predict that dilbit will weather (undergo physical and chemical changes) rapidly, becoming very dense and possibly sinking in a matter of days. If the dilbit reaches the sediment bed, it can be very difficult to get it out, and bringing in responders and heavy equipment to recover the oil from the sediments can injure the plants and animals living there.

To plan the cleanup and response and predict the impacts of future dilbit spills, we need more information on dilbit toxicity and on how quickly plants and animals can recover from disturbance. Knowing this information will help us balance the potential impacts of cleanup with the short- and long-term effects of leaving the sunken dilbit in place.

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