(Cowichan estuary)
‘High concentrations’ of fibreglass particles in Cowichan estuary raise concerns for birds and invertebrates
Industrial sites and marinas thought to be leading sources of particles
UPDATE: ON FEB. 4, 2026, COUNCIL APPROVED THE FOLLOWING MOTION BY COUNCILLOR CHRISTOPHER JUSTICE. ONLY COUNCILLOR TEK MANHAS OPPOSED, WITH NO REASONS PROVIDED.
"Council direct the Mayor to write to our MP and MLA and the appropriate regulatory authorities - including Environment and Climate Change Canada, Fisheries and Oceans Canada, the BC Ministry of Environment and Climate Change Strategy, Transport Canada, and any other appropriate regulatory body - to both raise awareness of and request action to address fibreglass pollution in the Cowichan Estuary, including actions to:
— investigate sources of contamination and enforce regulations;
— strengthen monitoring and regulatory oversight;
— support remediation, monitoring and community-led restoration efforts, and;
promote and support research on glass fibers entering the food chain”
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A new study has found “high fibreglass concentrations” in the Cowichan River estuary, raising concerns for bivalves such as mussels and oysters as well as shorebirds.
The Western Forest Products sawmill, Westcan Terminal, marinas and slipways are thought to be leading contributors of fibreglass pollution in the estuary based on sampling, the study said.
"The highest fibreglass concentration was found...at the mouth of the Western Forest Products mill pond." Upriver sources may contribute to the problem, but to a lesser extent.
(Western Forest Products sawmill at Cowichan Bay)
Fibreglass particles were present at 64.3 per cent of sediment sample sites in 2020 and 96.15 per cent in 2023, at a density of six to 286 particles per kilogram (dry weight).
Fibreglass particles at intertidal biofilm sample sites ranged from 30 to 62 particles per kilogram (dry weight).
“The presence of glass fibres embedded in these biofilms raises concerns,” the study found. “Migratory birds feeding on contaminated biofilms may inadvertently ingest glass fibres or fragments, posing serious health risks….”
(Greater Yellowlegs on Cowichan Bay mud flats. Special thanks to Ken Thorne.)
Fibreglass fragments having a higher density than seawater were more likely to be deposited deeper in sediments rather than onto the surface biofilm found within the top three-to-five millimetres of mudflats.
Invertebrate filter feeders such as mussels are also at risk from fibreglass particles accumulating in their “digestive tubules and gills,” the study added.
The Marine Pollution Bulletin, published in the journal Elsevier, involved Simon Fraser University, Cowichan Estuary Restoration and Conservation Association (CERCA), Ocean EcoQuest, and Environment and Climate Change Canada.
The lead author, SFU's Juan José Alava, also previously worked on the study at the University of B.C.
Goetz Schuerholz, president of CERCA, which helped lead what he calls "pioneering research," told sixmountains.ca on Saturday that further investigation into "the potential transfer of glass fibres up the food chain and the associated risks to human health" will be priorities in the next phase of the project.
The study calls for: better regulations, including at commercial boat-maintenance facilities; improved waste and end-of-life boat management practices; and increased monitoring and enforcement.
Fibreglass fragments are easily released during the cutting or sanding of boats and other structures manufactured, stored, and abandoned, as well as through normal decay and weathering processes, the study says.
A study in India also found that abandoned boats “contributed substantially” to the accumulation of fragments.
(Cowichan Bay derelict sailboat)
Fibreglass is a synthetic, hard, narrow, and elongated filament commonly used in various industries, including building and shipping, the Cowichan estuary study says.
It offers significant advantages over other materials such as concrete, steel, and other metals due to its high ratio of surface area to weight. It shares similar chemical and physical characteristics with asbestos.
(Sample sites in the study)
Read the full study: https://www.sciencedirect.com/science/article/pii/S0025326X25016637#f0005
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— Larry Pynn, Jan. 3, 2026