Study suggests that sea spray plays an important role in spreading perfluoroalkyl acid pollutants into the air

Oceans have long been considered the final resting place of perfluoroalkyl acids (PFAAs), toxic and persistent pollutants that have been widely used for decades in firefighting foams and other products. New research suggests these chemicals may be less settled in seawater than previously thought. Scientists have investigated the transport of PFAAs from the sea to the atmosphere via sea-spray aerosols formed from breaking waves, but these laboratory studies have struggled to realistically replicate sea spray. Now, using artificial seawater and a plunging water jet to create bubbles, researchers at Stockholm University found that PFAAs are enriched in sea-spray aerosol by up to a factor of 62,000 relative to bulk artificial seawater (Environ. Sci.: Processes Impacts 2019, DOI: 10.1039/c8em00525g). They estimate, in modeling studies, that more than 100 metric tons of each of two prominent pollutants, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), may be emitted annually into the atmosphere by sea spray. For comparison, industrial sources in China emit about 1–1.4 t of PFOS into the air annually, according to current estimates. The team plans to improve its estimates of PFAAs in sea spray by studying natural seawater on a research cruise later this year.