It's literally raining "forever chemicals" in Miami

FIU research finds PFAS aren't all from local sources, a sign these contaminants are spreading across the globe

MIAMI, Nov. 4, 2024 /PRNewswire/ -- PFAS are in Miami's rainwater, the latest evidence the synthetic "forever chemicals," which have raised health concerns, hitch a ride on the water cycle, using the complex system to circulate over greater distances.

FIU researchers analyzed 42 rainwater samples across three sites in Miami-Dade County and detected 21 perfluoroalkyl and polyfluoroalkyl substances, or PFAS. They included older varieties known as PFOS and PFOA that were phased out of production over cancer concerns, as well as newer varieties still used in manufacturing today.

While profiles of several PFAS matched local sources, others did not. According to the study, published in Atmospheric Pollution Research, this suggests Earth's atmosphere acts as a pathway to transport these chemicals far and wide — contributing to the worldwide pollution problem.

Widely used in consumer products, PFAS were created to be almost indestructible. Once in the environment, they accumulate over time. People can ingest or inhale them, and exposure has been linked to liver and kidney damage, fertility issues, cancer and other diseases. The EPA warned that even low levels of exposure can be dangerous, setting strict near-zero limits for some PFAS in drinking water.

"PFAS are practically everywhere," said FIU Assistant Professor of Chemistry and study author Natalia Soares Quinete. "Now we're able to show the role air masses play in potentially bringing these pollutants to other places where they can impact surface water and groundwater."

PFAS can infiltrate the atmosphere by either evaporation or getting absorbed into microscopic particles and dust. Wind and shifting air currents shuttle them along. Eventually, it rains. As each drop falls to earth, it brings along some of the pollutants. Then the cycle begins again.

Between October 2021 and November 2022, the most frequently detected and abundant PFAS in Miami's rainwater, in 74% of samples, were PFCAs — commonly used in non-stick and stain-resistant products, food packaging and firefighting foams. The researchers previously detected high levels of these compounds in nearby surface waters, a sign they're coming from local sources.

However, PFAS concentrations skyrocketed during the dry season (October through May), coinciding with Northeastern air masses moving into Miami. More emerging PFAS also made an appearance, including those typically found in North Carolina and other states, where facilities produce goods made with these chemicals.

Here's what the researchers suspect is happening: Drier air in northern currents creates perfect conditions for more PFAS-laden dust and particles to spread around. Rain "washing out" those pollutants from the air could account for higher contaminant concentrations.

Quinete, who heads the Emerging Contaminants of Concern lab in FIU's Institute of Environment, has been trying to piece together how these long-lived chemicals journey through the environment. Her research group is among the first to extensively track the prevalence of the persistent pollutants across South Florida. They've detected PFAS in drinking water and surface water, including Biscayne Bay. And, subsequently, also found PFAS in animals that live in those areas, including oysters and economically important recreational fish and lobsters.

As with their past research, the team hopes the data can help guide future solutions and regulations for controlling and reducing PFAS.

To read more about this research, visit FIU News.

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SOURCE Florida International University