Radioactive contamination in freshwater mussels is potentially affecting the food chain in Pennsylvania, including iconic animals such as bald eagles and possibly even humans.
A study published last year by scientists from Penn State University found elevated levels of radium in mussels downstream from a waste treatment facility in Franklin, Pennsylvania. Now, experts are raising the alarm over the secondary impacts on the ecosystem.
While the facility no longer discharges oil and gas wastewater into the Allegheny River, its legacy of pollution persists, with radioactive material bioaccumulating in the ecosystem.
Why This Matters
The findings highlighted that radioactive materials could be climbing the food chain, affecting not just aquatic life but also land animals, birds and people. Bald eagles, a species reintroduced to Pennsylvania in 1983, are among those at risk. Their diet includes muskrats, a primary predator of freshwater mussels, which are now confirmed to carry radium.
Although freshwater mussels are not consumed by humans, other species higher in the food chain may serve as a bridge for contaminants to eventually affect people. Local fishing activity in the Allegheny River also raises questions about indirect exposure to radioactive material.
Exposure to high levels of radium can result in adverse health conditions like anemia, cataracts, fractured teeth, cancer (especially bone cancer) and death, the U.S. Centers for Disease Control and Prevention says.
What To Know
Freshwater mussels act as ecological barometers because of their fixed locations and long lifespans.
In this study, researchers found that mussels downstream of the waste treatment facility had absorbed radioactive particles into their soft tissue and hard shells. Mussels closest to the discharge site perished from salinity, while those farther away adapted but at a cost—they absorbed contaminants instead.
The study also compared the mussels' radioactivity to Brazil nuts, which naturally absorb radiation from the soil. While a typical 28-gram serving of Brazil nuts contains 0.47 to 0.80 micro-sieverts, the maximum radioactivity found in a single mussel was 63.42 μSv.
While the International Atomic Energy Agency recommends an annual exposure limit of 1,000 μSv—far exceeding the amount found in even the most radioactive mussel—the findings are concerning because of the potential for radiation to accumulate within food chains over time.
What People Are Saying
Katharina Pankratz, a co-author of the study, said in a statement: "Depending on the contaminant and its chemistry, if it is small enough to pass through the gills of the mussel, it has the potential to accumulate in their tissue or precipitate within the hard-shell structure. This information may help shape future regulations for wastewater disposal to surface water, especially in regions where mussels are harvested for food."
Nathaniel Warner, the study's corresponding author, said in the statement: "Mussels that were closest to the water discharges died off. Further downstream, the mussels found a way to tolerate the salinity and radioactive materials and instead absorbed them into their shells and tissues."
Evan Clark, the waterkeeper at Three Rivers Waterkeeper, told Inside Climate News: "It's a similar situation to what Rachel Carson was warning about with DDT affecting animals up the food chain. The muskrats are depended on by bald eagles, and muskrats are probably the biggest consumer of the freshwater mussels."
What Happens Next
The study's findings could inform future policies on wastewater management, its authors said. While the waste treatment facility in Franklin is no longer discharging waste into the waterways, its impacts still linger and could do so for some time.
Key questions, such as how much radioactive material is accumulating up the food chain, remain. "The Allegheny River is pretty special," Clark said. "And we're just playing out a long-term experiment on ourselves and on our river."
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