Toxic PFAS “forever chemicals” that end up in the ocean boomerang back to shore after crashing waves re-emit them into air, according to a study by researchers at Stockholm University published in Environmental Science & Technology. The findings suggest this is a significant contributor to air pollution in coastal areas.
PFAS are a class of heat and water-resistant chemicals that are used in a wide variety of applications including flame-retardants, and non-stick and industrial products, and are contained in many consumer goods such as raincoats, cookware and packaging. The chemicals are known carcinogens that do not degrade in the environment or in the human body, which has earned them the nickname “forever chemicals”. They leach into groundwater from disposal sites and have been linked with cancer, learning and behavioural problems in children, infertility, increased cholesterol, and immune system problems.
The research team collected air samples from two coastal areas in Norway from 2018 to 2020. They found that air concentrations with the most PFAS were strongly linked to markers of sea spray aerosol. The findings indicate that these PFAS are transported from seawater to marine air by sea spray aerosols, which constitute a significant source of PFAS air pollution to coastal communities.
“The common belief was that PFAS would eventually wash off into the oceans where they would stay to be diluted over the timescale of decades,” said Matthew Salter, a co-author of the study and researcher at the Department of Environmental Science, Stockholm University. “But it turns out that there’s a boomerang effect, and some of the toxic PFAS are re-emitted to air, transported long distances and then deposited back onto land.”
Previous laboratory research by the team showed clear evidence that sea spray aerosol can be an important source of PFAS in the atmosphere. Now the new study provides field evidence that this is indeed true.
“It is possible that atmospherically deposited PFAS could contaminate coastal drinking water sources for the foreseeable future,” added Professor Ian Cousins, a co-author of the study. “Our study gives a new dimension to the meaning of the term forever chemicals. Even the PFAS we thought would be lost to the sea boomerang back for us to be exposed all over again.”