Have you ever seen a mussel? Those unassuming, bivalve creatures you might find clinging to rocks in rivers and streams? Well, they’re not just filter feeders, cleaning the water as they eat; they’re also living, breathing barometers of our environmental health. And a recent study from Penn State has unveiled a troubling tale these mussels are telling about the legacy of fracking.
Mussels, while not the most visually captivating of animals, play a crucial role in scientific research due to their unique lifestyle. They are stationary filter feeders, spending most of their lives anchored to one spot in riverbeds or lake bottoms.
This lack of movement means they constantly sample the water around them, absorbing both nutrients and any pollutants present.
Because they are essentially rooted in their environment for decades, mussels accumulate substances in their tissues and shells over long periods. This makes them exceptional indicators of environmental health, especially pollution levels.
Scientists can analyze the chemical composition of mussels to get a snapshot of what contaminants are present in the water, including harmful substances like radioactive materials.
Scientists at Penn State’s Department of Civil and Environmental Engineering initiated a study that focused on freshwater mussels inhabiting the waterways downstream from a wastewater treatment facility in Western Pennsylvania.
This specific facility had a long history of processing wastewater generated from hydraulic fracturing (fracking) operations in the Marcellus Shale, a significant natural gas reservoir that extends across multiple states in the region.
Despite the fact that the facility ceased accepting fracking wastewater in 2019, the mussels located downstream continued to exhibit elevated levels of radioactivity.
This suggests a potential long-term environmental impact of fracking activities and raises concerns about the persistence of radioactive contaminants in the ecosystem even after wastewater treatment.
The scientists found that these mussels, both in their soft tissues and hard shells, contained elevated levels of radium. This wasn’t just any radium, though. It had a unique elemental signature, like a fingerprint, that traced it back to the treated wastewater from fracking. Even years after the plant had stopped accepting this waste, the mark of fracking lingered in the river’s ecosystem.
“With a much higher salinity than the surrounding environment, the discharged water has a different chemical fingerprint than what the mussels are used to,” explained Nathaniel Warner, a professor involved in the study.
“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.”
To put this radioactivity of mussels due to fracking into perspective, the researchers compared the mussels to Brazil nuts, known for their natural radioactivity. Believe it or not, some of the mussels in the study were more radioactive than a serving of these nuts.
While not a direct threat to humans (we don’t typically eat these mussels), it does raise concerns about the potential impact on the animals that rely on mussels for food.
Katharina Pankratz, the lead author of the study, emphasized that mussels aren’t just filtering out radium.
“Along with nutrients, mussels also filter contaminants present in the water column, like metals, microplastics, synthetic chemical compounds and other emerging contaminants of concern,” she said.
This means the contamination could move up the food chain as larger creatures consume the mussels, potentially affecting endangered species that are particularly vulnerable.
This study is a stark reminder of the long-term consequences of industrial activities like fracking. While wastewater treatment facilities do their best to remove major contaminants, trace amounts inevitably remain.
And for creatures like mussels, these traces can accumulate over time, leaving a lasting legacy in their bodies and the environment.
Pankratz hopes the research will spark further investigations into the ecological consequences of wastewater disposal and potentially influence future regulations. The mussels, in their silent way, are sounding an alarm. It’s up to us to listen and learn.
The study is published in the journal Science of The Total Environment.
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