A new study conducted by scientists at Florida International University (FIU) has revealed that rainwater in South Florida contains high levels of per and poly-fluoroalkyl substances (PFAS), commonly referred to as “forever chemicals.” These pollutants are long-lasting, do not break down quickly, and have been linked to health concerns ranging from immune issues to cancer. This is the first study to analyze PFAS in South Florida rainwater, showing levels of these chemicals that exceed the Environmental Protection Agency’s (EPA) health advisory limits.
PFAS are synthetic chemicals developed over 80 years ago for their water-repellent, non-stick, and fire-resistant properties. They are widely used in non-stick cookware, water-resistant clothing, firefighting foams, and food packaging. Due to their persistence, PFAS remain in the environment long after use, accumulating in soil, water, animals, and humans. Exposure to these chemicals has been linked to severe health issues, including liver and kidney damage, reproductive problems, and some types of cancer.
FIU researchers collected 42 rainwater samples from various sites across Miami-Dade County between 2021 and 2022. They analyzed these samples to detect PFAS levels and determine potential sources. Here are some of the study’s key findings:
The PFAS detected in South Florida rainwater appears to come from local and distant sources. In South Florida, point sources such as military bases, firefighting training centers, and industrial facilities contribute PFAS to the environment. However, according to FIU’s data, air currents from northern regions may also carry PFAS pollution into South Florida.
The study’s findings highlight an overlooked pathway for PFAS contamination: atmospheric deposition, where chemicals in the air are brought down by rain. This means PFAS can infiltrate water sources far from where they were initially released, potentially contaminating surface water, soil, and drinking water supplies.
Natalia Soares Quinete, an assistant professor at FIU and lead researcher, emphasizes the importance of understanding how air masses move these pollutants across regions. “PFAS are practically everywhere,” Quinete said. “Our data shows how air currents can bring these pollutants to new areas, impacting water sources and wildlife.”
The study also uncovered a seasonal pattern in PFAS levels. Higher concentrations were detected during the dry season, particularly from October through May, when drier northern air masses reach South Florida. This seasonal variation suggests that colder, drier air may carry more PFAS-laden dust and particles, settling in the region’s rain.
With the EPA setting near-zero advisory limits for some PFAS in drinking water, these findings signal potential health risks for communities in South Florida. Although rainwater is not directly used for drinking, the deposition of PFAS into local soil and surface water could contribute to broader contamination over time.
FIU researchers hope this study will help inform local and national policies to control PFAS emissions and protect public health.
The discovery of PFAS in South Florida’s rainwater underscores the need for ongoing monitoring and stricter regulations on these persistent pollutants. Quinete and her team continue to explore PFAS in Florida’s environment, aiming to support policies that limit PFAS exposure and pollution.
“This study shows us that what happens in one area can impact many others,” said Maria Guerra de Navarro, a graduate student on the research team. “Addressing PFAS pollution is critical to safeguarding health and the environment for everyone.”
