It is literally raining eternal pollutants in this developed city ☠️

Miami's rain carries much more than just droplets of water. Researchers from Florida International University (FIU) have revealed that the rainwater in this region contains "forever chemicals," or PFAS, pollutants that, as they circulate through the water cycle, contaminate areas far beyond their initial sources.


For more than a year, the team collected 42 rainwater samples in Miami-Dade County, identifying 21 varieties of PFAS, including PFOS and PFOA, substances banned due to their carcinogenic risks. Despite being prohibited, modern versions of these compounds persist in consumer products and are showing up in the rains of South Florida.

Some PFAS found in the collected samples could be linked to local sources, but other substances appear to come from elsewhere. This atmospheric dispersion, reported in Atmospheric Pollution Research, shows that PFAS travel over long distances, amplifying global pollution.

Natalia Soares Quinete, assistant professor of chemistry and lead author of the study, explains that air and air masses carry these contaminants to areas where they eventually impact surface waters and groundwater, illustrating the extent of the contamination.

These substances are designed to be extremely resilient: products like food packaging, clothing, or non-stick cookware are made with PFAS that do not easily degrade. Once released into the environment, these chemicals accumulate, exposing humans and wildlife to risks such as liver damage, kidney problems, fertility issues, and even some cancers.

Quinete's team has been tracking the presence of these pollutants in South Florida for several years. PFAS have been detected in drinking water, surface waters like Biscayne Bay, and even in local wildlife, including oysters, fish, and lobsters—suggesting a chain contamination of ecosystems.

Rain, a logical stage in their research, has proven to be an unexpected vector. The phenomenon studied by the team shows that PFAS can evaporate or attach to airborne particles, circulating through air currents before being deposited on the ground via precipitation.

Between October 2021 and November 2022, PFCA compounds, commonly found in firefighting foams and packaging, were detected in 74% of the samples. Their concentrations increase significantly during the dry season when air currents from the north reach Miami, bringing PFAS produced in other regions.

Maria Guerra de Navarro, a doctoral student and co-author of the study, explains that dryness facilitates the dispersal of PFAS-laden particles, which are then deposited by rain. These observations help to better understand the dynamics of how these substances are transported.

With this new data, the researchers hope to influence measures to limit the spread of PFAS. Guerra de Navarro stresses the importance of this awareness: contaminants released in one region can pollute other territories, reminding us that preventing this pollution is a global challenge.