TORONTO, Sept. 01, 2026 – Coastal residents may be worried about exposure to forever chemicals from sea spray during hot summer months, but York University researchers found there was little evidence of per- and polyfluoroalkyl substances (PFAS) contamination from marine aerosols, a finding that surprised them.
The study looked specifically at areas impacted by sea spray from the Atlantic Ocean generated by waves breaking on the coast of Newfoundland and Labrador, however, despite its windy, marine location they found it was not an issue as previously thought.
"We designed this study specifically to see if sea spray was contributing to a mobilization of PFAS in coastal regions and Newfoundland is a great place to do that. It's a marine location and it's very windy so we expected there to be quite a lot of PFAS from sea spray," says senior author Professor Cora Young , an atmospheric chemist and Guy Warwick Rogers Chair in York University's Faculty of Science. "We were quite surprised we didn't see anything that would indicate sea spray was contributing to PFAS in the area."
Earlier international studies using mainly modelling and lab work had found sea spray to be a significant and direct source of forever chemicals. Lead author York PhD student Daniel Persaud, Young and the team conducted field work on the ground to understand the extent of the problem, expecting their results to support the former findings, but that is not what happened.
The researchers collected and analysed both wet and dry deposition samples from precipitation, such as rain, and dust that settled on the ground from particles and gases in the atmosphere at several locations up to 30 kilometres from the eastern coast. The researchers focused on forested watersheds in the Newfoundland and Labrador Boreal Ecosystem Latitudinal Transect, which are all influenced by marine aerosols and were selected because of their proximity to the ocean.
"Because the sites are windy and close to the ocean, we expected a strong marine-aerosol signal. Instead, the measured PFAS showed little association with sodium, which we used as a tracer of sea spray," says Persaud.
They did find PFAS at all study sites, but evidence pointed to a break down of PFAS precursor compounds in the atmosphere, which would have been transported from elsewhere and not from sea spray. They mostly found perfluoroalkyl acids (PFAAs), a subclass of PFAS, including perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkanesulfonic acids (PFSAs), which are not from local sources in Newfoundland.
Instead, these PFAAs likely came from industrial and commercial centres elsewhere in Canada and the United States, and potentially even further afield. PFAAs and their PFAS precursors are typically found in firefighting foams, non-stick materials and performance chemicals and can be transported long distances, including the Arctic, raising environmental and bioaccumulation concerns.
The researchers say their results are not necessarily exclusive to the east coast of Canada either as Newfoundland offers a worst-case scenario in terms of the amount of driving wind, crashing waves and extensive coastline, exacerbating the amount of sea spray and creating the perfect storm for forever chemicals. "This sort of sea spray is really not a major source global pollution according to our study," says Young.
One of the interesting findings pointed to the extent dry depositions contribute to PFAS in the environment. The researchers measured for both wet and dry depositions in this research, but that is not universally done and their results underline the importance of doing so to understand the full impact of PFAS in the environment.
"It's something that hasn't been understood but helps us to better predict where we're going to find forever chemicals when they're moving around the globe and where they will ultimately end up," says Persaud. "Understanding the difference between wet and dry depositions really helps not only us but other researchers going forward."
PFAS are not only found in rain and snow, but Young says she still finds it surprising that dry deposition remains so important even in a place like Newfoundland where it rains quite a lot, but it also points to the importance of including dry depositions of PFAS in studies to better understand where they are being deposited, how they are getting there and the environmental impact, whether that's a remote desert or the Arctic far from the pollution source.
The York researchers worked with scientists at Memorial University in St. John's, where Young previously worked and collected samples, the Canadian Forest Service, Natural Resources Canada in Corner Brook, and the Aquatic Contaminants Research Division, Environmental and Climate Change Canada in Burlington, ON.
"I see it as good news story. We worried the PFAS could move from ocean to land and back forever, but it doesn't seem like it's as big of a problem as we thought," says Young.
The paper, The Occurrence of Legacy Per- and Polyfluoroalkyl Substances (PFAS) Deposited along a Latitudinal Transect in Newfoundland and Labrador, Canada , was published in the Royal Society of Chemistry journal of Environmental Science Processes & Impacts.
