“A lot of the reason that we find that birds are getting hit by cars is because of poisoning. It is dulling their senses. It’s making them dizzy, disoriented,” Sheida Soleimani says. Soleimani is the founder and executive director of Congress of the Birds, a wildlife rehabilitation center in Providence.

Soleimani cannot be 100% sure that birds alongside the Centredale Superfund site are experiencing poisoning from dioxin, a highly toxic pollutant, because Congress of the Birds does not have the resources to complete testing, but she has seen birds suffer from classic signs of dioxin poisoning, like eggshell thinning and congenital defects. 

For over 25 years, local officials have worked to acknowledge and clean up the North Providence Centredale Manor Superfund site where dioxin was first identified in portions of the site’s sediment along the Woonasquatucket River. Local residents know not to enter the river, but birds and animals don’t have the same awareness.

Dioxin may not be the immediate cause of  bird deaths, Soleimani says, but it can increase their likelihood of injury. Soleimani estimates that 80% of the birds she treats suffer from neurological trauma, and there is a correlation between the likelihood of injury and contaminant exposure. Centredale Manor may be stuck in a past age of contamination, but local wildlife and ecosystems are actively experiencing the consequences of remaining dioxin, which has devastating effects on wildlife, with ripple effects beyond the Superfund site.

Elena Duran, a doctoral researcher at the Schubat Center at Texas A&M University, found the impact of dioxin is particularly potent for younger birds. Research by Duran and colleagues in 2024 demonstrated that a mother bird can consume the dioxin through finding food in the contaminated sediment, migrate to a new location and lay her eggs, and then bring those contaminated eggs into a new environment. If another predator consumes those eggs, the dioxin has now spread beyond the reach of the original site.

Steve Ormerod, an ecology professor at Cardiff University, describes birds as “very conspicuous species.” By paying close attention to biodiversity loss, he says, researchers can use birds to demonstrate the impact of pollutants within an ecosystem. When an ecosystem is disrupted, specialists, species with more specific diets that are more sensitive to disruptions, are most likely to die off. They serve distinct roles because they demonstrate when an environment is no longer stable enough to sustain them.

Congress of the Birds is also actively working with the Audubon Society of Rhode Island (ASRI) to test for other potential contaminants. Last year, Soleimani was specifically focused on rodenticide poisoning, so she provided four dead birds to be tested. In order to work with Rhode Island legislators, they needed concrete testing instead of suspicions. Soleimani says that all four birds they tested came back with extremely high levels of rodenticide poisoning, with a bald eagle having the highest.

“Whether we are talking about seabirds or grazing birds, we have to recognize that what they are being exposed to we are also being exposed to,” Duran says. Ultimately, humans can attempt to avoid dioxins in the environment, but leaving dioxins and other contaminants untreated will impact human health as well.

Originally, Centredale Manor was added to the Environmental Protection Agency’s (EPA) National Priorities List (Superfund) in 1999. Despite this formal recognition as a Superfund site, large areas remain contaminated. Tim O’Connor, the Woonsaquatucket River Watershed Council’s (WRWC) consultant on the Technical Advisory Group (TAG) for the Superfund site, says the delay in cleaning up the site is due to challenges in identifying a place to dispose of the dioxin. “There’s only one incinerator in the United States that can take dioxin-contaminated media for disposal,” he says.

Superfund sites are extremely litigation-orientated, which is also a cause of the 25-year long delay. According to O’Connor, the EPA first has to identify the party at fault, go to the performing party and fine it, and ultimately work with them to create a general action and remediation plan. In 2012, the EPA identified the responsible parties, and in 2018, the EPA and two of the responsible parties, Emhart Industries Inc. and Black & Decker Inc. (branches of Stanley Black & Decker Inc.), reached a $100 million settlement to clean up the site. But because of the challenges with disposal, the project remains incomplete.

O’Connor says the source area has been permanently capped, ensuring that no more dioxin will enter the rest of the river. The site has four areas in total, including three other areas that have had preparatory work done. Because the responsible parties remain unable to identify a disposal site, Centredale Manor is at a standstill and no work can be done beyond the preparatory work until an agreement has been established with a disposal site. O’Connor estimates that once they identify a disposal site, it will take approximately 4-5 years to fully remediate the remaining sites.

“I think a reasonable person could look at the schedule of how long it’s taken to get to this point and say, ‘man, this is an incredibly long period of time and it just makes no sense at all that it would take this long,’ but the Superfund is dealing with the nation’s most complex hazardous waste sites,” says O’Connor.

Centredale Manor is also especially complicated in the way that the dioxin is in the river’s sediment. O’Connor says that often Superfund sites include lagoons, landfills, and areas that were previously used for waste disposal. Additionally, dioxin is an incredibly rare contaminant, making it a very unique site to clean up. 

Although nothing can be done at the moment to clean up the remains of dioxin, Duran suggests small actions that community members can take to support bird communities, like ensuring that birds have access to clean water and food and regularly maintaining bird feeders to prevent disease from building up. The Audubon Society of Rhode Island also runs an Avian Research Initiative to monitor and collect data and identify birds that may need additional support. These data allow the Audubon Society to create a management plan that aims to help birds flourish within their habitats. Their volunteer-based initiatives allow interested community members to monitor local bird populations, help keep track of the insect populations that the birds need to eat, and more.

Although the WRWC is actively working with the community to ensure that members are educated, dioxin will remain in the environment.

“Birds are powerful indicators of the general health in our environment,” says Ormerod. As treatment awaits for the site and birds continue to consume dioxin, they serve as a glimpse of what humanity may be up against. “Our fate is tied to the fate of rivers and streams,” Ormerod says. 

Soleimani recognizes the heartbreaking reality of seeing birds without eyes, with defects, and more. “You can’t ask them if they’re suffering, but you can see it,” she says. At this point, it is no longer about harm prevention, but more about harm reduction. Soleimani says that humans may no longer be able to entirely remove contaminants like dioxin from the food chain, but they can educate themselves to reduce environmental pollutants to the best of their ability.

This story was published as part of a collaboration between ecoRI News and students in Brown University’s Science Journalism class. The stories examine the science, history, and human experiences connected to the Ocean State’s rivers — from water quality and wildlife restoration to flooding, pollution, social justice, and the communities working to protect them. To read more of these stories, click here.