USGS Studies PFAS Impact on Amphibians

In a recent article cited below and published in the journal Environmental Toxicology and Chemistry, scientists from Purdue University and the U.S. Geological Survey (USGS) studied the effects of PFAS pollution in water on tadpoles of three amphibian species. These three species are found throughout a wide portion of the U.S. and represent the three major amphibian groups that exist in our country.

PFAS or Per- and Polyfluoroalkyl (PFAS) substances are known as “forever chemicals” because they build up in animal tissues including blood and vital organs, bioaccumulate, and do not break down in the environment. We are still learning about the impact of PFAS on the ecology and human health. In 2009 the EPA set the first health advisory level (HAL) for PFOA and PFOA at 400 ppt each. In 2016 EPA reduced the health advisory level to a combined 70 ppt for PFAS. They have not yet established a health based MCL.

In this study, the scientists at Perdue and the USGS found that northern leopard frogs and eastern tiger salamanders were generally more susceptible to PFAS than American toads. 

“Amphibians are vital to ecosystem health, but can be sensitive to environmental stressors like chemical contaminants,” said Wes Flynn, a USGS scientist and the lead author of the study. “Our study shows that the effects of PFAS in surface water on amphibians is highly dependent on the species being exposed.” 

Aqueous film-foam release in Manassas, VA

PFAS can enter waterways from industrial and consumer activities and products, including the foams used to suppress gasoline, jet fuel and oil fires. Aqueous film‐forming foams are essential to effectively suppress fires associated with hydrocarbon‐based fuels, including gasoline and jet fuel, and are widely used at airports, military bases, chemical plants, and other industrial fire training areas. These aqueous film-forming foams are used to protect human life and property, but unfortunately they are becoming ubiquitous at trace levels.  

For this study, researchers used various concentrations of four PFAS that are found in surface water impacted by aqueous film‐forming foams use. They found that the chemicals affected size, body condition and speed of development of the tadpoles. All PFAS concentrations tested affected frogs and salamanders, but the toads, which develop into adults more quickly, were only affected by the highest levels not likely to be found in the environment.

The effects of PFAS on larval development differed between species. Frog development was delayed in the 10‐μg/L (ppb) PFHAS, 100‐μg/LPFOS, and 1000‐μg/L PFOS treatments while toads, development was only impacted by1000‐μg/L PFOA unlikely to be found in the environment.   

"Our results show that some amphibians could suffer health effects at sites highly contaminated by these PFAS present in fire-suppressing foams,” Flynn said. "More work is needed to determine whether such exposures could contribute to population declines. Our results indicate that evaluating the toxicity of PFAS using a single species is not sufficient for protective amphibian risk assessment. Future studies are needed.”

As a side note, in early March 2021 the Environmental Working Group (EWG) released the results of an analysis, they commissioned of tap water samples taken from various location throughout the Northern Virginia region. The EWG reported that they detected total PFAS in 19 samples of tap water ranged from about 6 parts per trillion, or ppt, in a state park in Fairfax County, to about 62 ppt in a public park in Prince William County. In 2019 the EWG had reported that the results from the sampling conducted as part of the EPA’s Unregulated Contaminant Monitoring Rule 3 from 2013 to 2015.  All results in Fairfax were non-detect, meaning that all results were below the detection limit of the test used. The Prince William County Service Authority Eastern service area was found to have 12 ppt of PFAS in 2014. Remember, 1 ug/L = 1,000 ppt so the levels found in the water supply in northern Virginia at various points were much lower than the levels the amphibians were exposed to.  

Flynn, R.W., Hoover, G., Iacchetta, M., Guffey, S., de Perre, C., Huerta, B., Li, W., Hoverman, J.T., Lee, L. and Sepúlveda, M.S. (2022), Comparative Toxicity of Aquatic Per- and Polyfluoroalkyl Substance Exposure in Three Species of Amphibians. Environ Toxicol Chem, 41: 1407-1415. https://doi.org/10.1002/etc.5319