Sea spray could be dousing you in toxic "forever chemicals" — study

It’s a perfectly pleasant day for a stroll on the beach. The Sun shines overhead while wet sand clings to your bare feet. As you turn to face the ocean, a gust of sea breeze blows through your hair, giving it a classic windswept look. And transports toxic chemicals into your body to linger there long after you towel off.

Sounds idyllic.

What’s new — A study published Wednesday in the journal Environmental Science & Technology finds that sea spray can transport chemicals, known as PFAAs, into your body via airborne particles. These chemicals are of “high global concern” to humans.

The findings have serious implications for understanding how these toxic chemicals make their way into the atmosphere and affect human health, especially for coastal communities.

“PFOS, PFOA, and many other PFAAs are highly enriched on sea spray aerosol and can be transported back to the atmosphere from the oceans,” the paper’s authors tell Inverse in a joint interview. Co-authors Bo Sha, Ian Cousins, and Matthew E. Salter are researchers in Stockholm University’s Department of Environmental Science.

Some background — Forever chemicals, known as per- and polyfluoroalkyl substances (PFAS) are toxic chemicals that don’t break down as quickly as other compounds, lingering for years in the atmosphere, environment, and even human blood.

“All PFAS are synthetic and will never degrade in the environment, and we only have information on the toxic effects of a few substances in the class,” the scientists explain.

How they made the discovery — To shed more light on these toxic effects, the researchers in this study analyzed a class of PFAS known as perfluoroalkyl acids (PFAAs). PFAAs include the substances perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA).

PFAAs have been used since the 1950s in industrial and commercial facilities to make products like paint and foam. They’re listed on the Stockholm Convention — a treaty to protect humans from environmental pollutants — and are “chemicals of high global concern,” according to the researchers.

Typically, PFAAs are emitted into the atmosphere in one of three ways:

1. Direct emissions from manufacturing plants
2. The degradation of volatile chemical compounds in the atmosphere
3. Water-to-air transfer from sea spray aerosol emissions

Most PFAAs released into the environment are transported into the ocean by rivers or rainfall. The scientists explain most people think pollutants in the ocean will become diluted to the point where they don’t affect us anymore. But that belief is woefully misguided, as PFAs can make their way back to humans through small droplets of sea spray.

To confirm the relationship between sea spray and PFAAs, researchers collected 48 aerosol samples between 2018 and 2020.

“...past emissions will likely keep haunting us for quite a long time.”

They retrieved the samples from two locations in Norway: Andøya and Birkenes. Andøya is closer to the coast (0.8 miles) compared to Birkenes (12 miles).

From there, they used mathematical models to establish the correlation between PFAAs and sodium ions — an indicator of sea spray.

What they found — The researchers discovered three key findings about toxic chemicals in sea spray:

1. PFAAs were found in all sea spray samples taken from both coastal locations, suggesting that sea spray “can be an important source of PFAAs to the atmosphere in coastal areas.”
2. Some of the various PFAA types associated with sea spray were found in higher concentrations in Andøya — the coastal community closer to the sea. But the fact that PFAAs were also associated with the farther-away Birkenes shows how sea spray can carry these chemicals far from coastal communities into urban areas as well.
3. While lab evidence had already confirmed the relationship between PFAAs and sea spray, this study is the first to provide direct field evidence of the high concentrations of toxic chemicals unleashed into the atmosphere by the ocean breeze.

“While we already had lab evidence of enrichment of PFAAs on sea spray aerosols, we were surprised that there was such clear evidence of the importance of [sea spray aerosol] as a source of PFAAs to the atmosphere,” the researchers say.

Why it matters — The findings pose serious concern for not just casual beachgoers and coastal residents, but to a majority of humans — sea spray sends the toxic chemicals hundreds of kilometers into the atmosphere.

“More than half of the global population lives within 100 kilometers of the coast, and PFAAs transported via sea spray aerosol may pose an extra risk to humans in addition to other sources of PFAAs,” the researchers state.

The researchers add that a fraction of PFAAs that we emit — such as from manufacturing production — will continue to circulate between the oceans and atmosphere in a horrific loop.

“And, because they never degrade, even if we manage to eliminate the use of PFAAs, past emissions will likely keep haunting us for quite a long time,” the researchers grimly conclude.

What’s next — This study is just cracking the surface of the researcher's investigations into sea spray and PFAAs.

Future studies will include gathering more field data from atmospheric monitoring stations, but the researchers hope to shed more light on this little-studied area of sea spray aerosol, which is transporting toxic chemicals around the globe.

Their findings serve as yet another cautionary tale of using chemicals in products for short-term use while ignoring their potential long-term impacts on the environment and health.

The researchers urge that policymakers must “carefully balance the pros and cons” when deciding whether PFAS should be approved for commercial applications.

They argue for the essential-use concept: only use PFAS if it is “necessary for health, safety or is critical for the functioning of society”

“We hope that policymakers will be more cautious when approving new PFAS in the market,” the researchers argue.

Abstract: The effective enrichment of perfluoroalkyl acids (PFAAs) in sea spray aerosols (SSA) demonstrated in previous laboratory studies suggests that SSA is a potential source of PFAAs to the atmosphere. In order to investigate the influence of SSA on atmospheric PFAAs in the field, 48 h aerosol samples were collected regularly between 2018 and 2020 at two Norwegian coastal locations, Andøya and Birkenes. Significant correlations (p < 0.05) between the SSA tracer ion, Na+, and PFAA concentrations were observed in the samples from both locations, with Pearson’s correlation coefficients (r) between 0.4−0.8. Such significant correlations indicate SSA to be an important source of atmospheric PFAAs to coastal areas. The correlations in the samples from Andøya were observed for more PFAA species and were generally stronger than in the samples from Birkenes, which is located further away from the coast and closer to urban areas than Andøya. Factors such as the origin of the SSA, the distance of the sampling site to open water, and the presence of other PFAA sources (e.g., volatile precursor compounds) can have influence on the contribution of SSA to PFAA in air at the sampling sites and therefore affect the observed correlations between PFAAs and Na+.