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Toxic ‘forever chemicals’ found in Florida oysters

In a sample of 156 oysters taken from three different locations throughout the state, harmful “forever chemicals” were detected in each specimen analyzed.

Story at a glance


  • Perfluoroalkyl and polyfluoroalkyl (PFAS) and phthalate esters (PAEs) have been linked with adverse health effects in humans.

  • The chemicals are widely used in consumer products such as makeup, cookware and clothing.

  • Researchers warn the levels seen in the oysters might be a bellwether for unhealthy contaminants in drinking water. 

Perfluoroalkyl and polyfluoroalkyl (PFAS) and phthalate esters (PAEs) are known as “forever chemicals” due to their inability to completely break down in the natural environment and their widespread use in consumer and commercial products

When researchers from Florida International University recently tested for the chemicals in 156 oysters from Biscayne Bay, Marco Island, and Tampa Bay, they found detectable levels in every single oyster. 

Because oysters are filter feeders, meaning they obtain food by filtering matter and organisms from water that passes through them, the species can reveal a lot about an ecosystem’s overall health.

The findings confirm the pollutants are in multiple water sources and have infiltrated the food chain. The chemicals have been found in human and animal blood and in the natural environment.

Oysters collected from Biscayne Bay had the highest concentrations of most PFAS and PAES compounds compared with the other two locations, despite being the smallest specimens sampled. This is surprising given that the more time an oyster grows, the longer it has to become contaminated.


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In comparison, the largest oysters, found in Tampa Bay, had the lowest levels of contaminants reported, suggesting the water there might be less polluted than in Biscayne Bay. 

“Biscayne Bay could be so contaminated, the oysters are bombarded with such high concentrations they accumulate contaminants more quickly,” explained researcher Leila Lemos in a press release. 

PFAS and PAES could also be hindering oysters’ growth, as analyses showed higher levels of PFAS in water were associated with thinner shells.

Researchers said the health risks for humans consuming the oysters are low, although they only studied a small group of PFAS and PAES compounds. 

“It’s important to also remember that there’s so many other exposure paths for both PFAS and PAEs compounds, like drinking water,” Lemos continued. 

One recent analysis of U.S. drinking water found levels of PFAS are likely higher than tests conducted by the Environmental Protection Agency are designed to show. PFAS can affect reproduction and human development, along with immune system functioning, and have been shown to interfere with vaccine efficacy. 

PAES have also been linked with diabetes, allergies, asthma and obesity. 

Published on Jul 07,2022