A wrecked, abandoned boat is seen in the Cowichan Estuary on Vancouver Island in April. New research found significant levels of fibreglass contamination in the estuary, which experts say can be traced to abandoned vessels like this one.Jesse Winter/The Globe and Mail
A flock of shorebirds burst into the air, circling the mouth of the Cowichan River before settling back onto a rocky sandbar to feed.
Migratory birds such as Western sandpipers feed on the biofilm – a fatty surface slime of diatoms and bacteria – that forms in these intertidal mud flats. The micro-organisms it contains provide crucial nutrients for their epic journeys between Central America, Alaska and Siberia.
But new research from the Cowichan Estuary Restoration and Conservation Association, in partnership with British Columbia’s Simon Fraser University, shows that the food source may come with hidden risks.
Scientists found concentrations of tiny fibreglass fragments in the Cowichan Estuary’s biofilm and even more in the estuary’s sediments – raising concerns that fibreglass in marine environments could become a new “forever” contaminant.
Fibreglass particles are tiny, near-microscopic spear-like shards, sometimes coated in plastic or resins, that result from industrial and construction uses, as well as regular boat maintenance. But unlike microplastic pollution, the effects of fibreglass contamination in marine environments is a relatively understudied issue.
“We are just in the infancy of understanding their potential toxicity for animals and people,” says Juan José Alava, a marine eco-toxicologist at SFU and lead author of the study.
Retired marine biologist and CERCA board member William Heath told the association that fibreglass particles 'may be even a bigger problem than microplastics.'Jesse Winter/The Globe and Mail
Researchers from the Cowichan Estuary Restoration and Conservation Association had originally set out to study microplastics in the estuary years ago. But then William Heath, a CERCA board member and retired marine biologist, came across a paper about fibreglass particles.
“I said, you know, this may be even a bigger problem than microplastics, and we should look into this,” said Mr. Heath, who has been helping the association study microplastics and other contaminants in the estuary for years.
And so the organization reached out to SFU for help.
Researchers took biofilm and sediment samples from 26 different sites around the estuary in 2020 and 2024. They found the highest concentrations of fibreglass contamination in three areas: near the Western Forest Products lumber mill; the Cowichan Bay Marina; and the Westcan Terminal, a decades-old industrial spit that today houses a stevedoring operation and a marine construction company.
Juan José Alava, a marine eco-toxicologist at SFU and lead author of the study says the contamination in the estuary’s sediment could also pose a hazard to urchins, bivalves and other shellfish that are key food species not just for birds and wildlife.Jesse Winter/The Globe and Mail
The results of the study, published in March in the peer-reviewed Marine Pollution Bulletin, provided one of the first baseline assessments of fibreglass contamination in Canadian ecosystems.
The findings have implications for sites of critical biodiversity across B.C. The Roberts Bank mud flats, near Tsawwassen First Nation south of Vancouver, are another vital biofilm location and stopover for migrating birds: Scientists believe that every Western sandpiper in the world will visit there to rest at least once in its lifetime.
The contamination in the Cowichan Estuary’s sediment could also pose a hazard to urchins, bivalves (such as clams and oysters) and other shellfish that are key food species not just for birds and wildlife, but for people, Mr. Alava said.
“There is a basic principle in environmental toxicology that the dose makes the poison. But we don’t know – even for microplastics – what that dose is yet,” he said. “We know that they are in the brain, in several tissues of humans and animals, but we don’t know the toxicity … the effect.”
One of the biggest unknowns is whether fibreglass bioaccumulates through the food chain the way some scientists believe microplastics do, Mr. Alava said.
Images captured with a scanning electron microscope show tiny shards of fibreglass contamination found in the biofilm and sediment of the Cowichan Estuary.Simon Fraser University/Supplied
More study is needed to fully understand the risks, he added, but “we don’t have to wait until the pollution is in the environment to really take action. It might be too late.”
Mr. Heath said the CERCA/SFU research is believed to be the first time such a study of marine fibreglass has been done in North America. Even globally, it marks one of the few times the risks of contamination have been highlighted.
A similar discovery happened in the south of England eight years ago, when British researcher Corina Ciocan set out to study microplastic concentrations in Chichester Harbour, a popular sailing destination.
The area used to be so famous for its oysters that Queen Victoria reportedly would order batches of them. But by 2018, the shellfish had died off and the fishery closed. Ms. Ciocan wanted to understand why, and teamed up with a local conservation group to study the harbour’s estuary.
“Instead of microplastics, we actually found fibreglass,” Ms. Ciocan said. “There were those tiny, transparent tubes that you can see under the microscopes. We had no idea what they were, because nobody had reported those previously in the scientific literature.”
Ms. Ciocan has since been trying to raise the alarm. After cataloguing the scale of contamination, she and her team conducted lab experiments to study how the fibres affected marine life such as mussels, zooplankton and water fleas.
She found that even at relatively low concentrations, the fibres embed in the tissues of bivalves, causing inflammation and – at the concentrations her lab tested – rapid mortality.
“We found fibreglass and plastic in the digestive gland, so they clearly ingested the material. The digestive tubules were absolutely clogged with this material. So the animal was probably doomed to starve,” Ms. Ciocan said.
Her research identified abandoned vessels as a significant contributor to fibreglass pollution. The vast majority of modern pleasure boats and sailboats have hulls and other components made of the material, which eventually breaks down.
Both Ms. Ciocan and Mr. Alava’s research highlighted marine boatyards as a potential source of contamination. Keeping a fibreglass sailboat in working order means scraping barnacles and other buildup from the hull, plus sanding (and repainting) it every few years.
But even inactive vessels can be a significant source. Across Canada the federal government tracks reports of abandoned boats and logs them in a publicly available database. The most recent numbers show there are 1,355 abandoned boats across the country, with nearly 70 per cent of them in British Columbia waterways.
Getting rid of the vessels is often challenging and expensive; even just tracking ownership can be tedious work. Enforcing cleanup falls to the Canadian Coast Guard, which began implementing heavy fines in 2019 to help address the problem.
Since then, around 800 vessels have been removed, and the federal government has issued nine fines against vessel owners totalling more than $120,000, according to a federal database.
The Western Forest Products sawmill in the Cowichan Estuary. Researchers found high concentrations of fibreglass particle contamination near the mill.Jesse Winter/The Globe and Mail
Mr. Alava’s research with CERCA also found high concentrations near the Cowichan Estuary’s industrial sites, where the exact source of contamination remains unclear. Why, for instance, would there be high amounts of fibreglass in the sediment near a lumber mill, which is not involved in fibreglass manufacturing or vessel maintenance? Mr. Alava and the team from CERCA hope to find those answers with further rounds of research.
Ultimately, he wants to see much more stringent regulations adopted in Canada to try to address the growing concerns now, before the problem gets any worse.
In particular, he would like to see tighter controls around sanding and cutting on slipways and boat yards, stronger regulations around derelict vessels, improved runoff control for marine industrial sites and the development of “green chemistry” alternatives to fibreglass that can reduce ecological harm.
“Just knowing these particles are present in an estuary that supports shorebirds and shellfish – and is central to Indigenous food security – is enough to justify preventive, precautionary actions.”