Persistent pollutants are invading the Amazon. Far from industrial zones, worrying traces of toxic substances are persisting in the air above the rain forest.
These compounds, called PFAS, are being carried over thousands of kilometers, all the way to one of the most remote regions on the planet.
Researchers have measured abnormally high concentrations of PFAS at different altitudes, thanks to a tower located in the heart of the forest. This finding challenges the idea that the Amazon would be shielded from global industrial pollution.
PFAS, initially developed for their non-stick, stain-resistant, and waterproof properties, have spread throughout the Earth's atmosphere for decades, gradually accumulating in every environment. These chemical compounds are now ubiquitous in the environment and have even been detected in regions as remote and pristine as the Amazon, highlighting their ability to travel very long distances.
The study, published in
Science of the Total Environment, reveals that winds play a key role in transporting these substances from industrial centers, like Manaus, hundreds of kilometers away.
To reach this conclusion, scientists installed sensors on the Amazonian Tall Tower Observatory (ATTO), a 325-meter (1,066 ft) high structure, to measure PFAS concentration at various altitudes. Over two weeks, they collected air samples, revealing a concentration of 0.09 picograms of PFOA (one of the PFAS variants) at ground level and up to 2 picograms at 320 meters. These results indicate long-distance airborne transport of pollutants, rather than local contamination.
Scientists are particularly concerned about the effects these molecules may have on Amazonian wildlife. The disruption of reproductive systems caused by these pollutants could be fatal for certain species. Ivan Kourtchev, an atmospheric pollutants specialist, emphasizes that PFOA interferes with reproductive hormones, severely impacting local biodiversity.
Experts are calling for further research to fully understand the scope and source of this pollution, as well as its long-term consequences on the Amazon. These discoveries once again highlight the scale of the environmental challenges linked to persistent pollutants, capable of reaching even the most protected regions of the globe.
What are PFAS and why are they dangerous?
PFAS, or per- and polyfluoroalkyl substances, are synthetic chemical compounds created in the 1950s for their non-stick and waterproof properties. They are widely used in everyday products such as cookware, food packaging, and textiles.
Their unique feature is their exceptional resistance to degradation. They are referred to as "forever pollutants" because they persist indefinitely in the environment. Their accumulation in ecosystems and the human body is concerning, as studies have linked PFAS with serious health issues, including cancers, fertility disorders, and hormonal disruptions.
How do PFAS travel long distances?
PFAS can be transported over thousands of kilometers by atmospheric phenomena. Once released into the air by industrial processes, they attach to tiny particles or evaporate, then travel with wind currents. This ability to spread over vast distances explains their presence in remote regions such as the Amazon.
Where they would not typically be expected, these pollutants settle into natural ecosystems. Rain, snow, or other precipitation bring them back to the ground, where they infiltrate the soil and water systems, contaminating sensitive ecosystems.
Article Author: Cédric DEPOND