Collaborative Research on Microplastics in two Vancouver Island Estuaries 

Project Watershed, in collaboration with SFU, UBC, and Cowichan Estuary Research and Conservation Association recently published a paper on their shared research within the K’ómoks and Cowichan Estuaries. This work was looking to examine microplastics pollution in two estuaries and determine if there were differences within the two estuaries based on their current industrial and development uses. The K’ómoks Estuary which mainly faces threats from continued urban development was compared with the Cowichan Estuary which still sees industrial uses like forestry and associated shipping.  

You can find the full article here but we’ve also summarized key take aways in this post.

We’d like to give a big PW thank you to all the authors including Zeinab Zoveidadianpour,  Juan José Alava, Mark C. Drever, Goetz  Schuerholz, Caitlin Pierzchalski, Tristan Douglas, William A. Heath, Bernhard Juurlink, and Leah Bendell. Furthermore, we’d like to thank the funders from both Mitacs Canada and private donations which supported this work.

What Are Microplastics? 

Microplastics (MPs) are tiny plastic fragments, fibers, pellets, or films measuring less than 5 millimeters. They come from broken-down plastic waste, synthetic clothing fibers, fishing gear, and even personal care products. Because of their small size, these particles often end up in the environment, where they can be ingested by marine animals and travel up the food chain. 

What did we look at?  

Researchers analyzed sediments and varnish clam for microplastics using Fourier transform infrared spectroscopy (FTIR) analysis. This allowed researchers to determine the number and type of microplastic fibers and filaments which were present in both sediment and varnish clam gut samples. The goal of sampling of varnish clams was to see if microplastics from sediments were moving up the food chain and into the gut tissue of clams. Varnish clams were selected because they are feeding within sediments rather than filter feeding in water.  

The Findings: Microplastics Are Everywhere 

• Sediments: Every sediment sample collected contained microplastics. K’ómoks had nearly twice the concentration of MPs (30.96 particles/kg) compared to Cowichan (14.37 particles/kg). 

• Clams: Varnish clams also contained microplastics, with Cowichan clams averaging 3.62 particles per gram and K’ómoks clams averaging 2.24 particles per gram. 

• Most Common Types: The majority of microplastics found were fibers, likely from textiles, followed by plastic fragments from broken-down materials. 

• Polymer Composition: In Cowichan, polyethylene (common in packaging) was the dominant plastic, while polyester (widely used in clothing) was more prevalent in K’ómoks. 

• Hotspots: The Cowichan marine terminal and Comox Marina sites had the highest concentrations of microplastics, suggesting that human activities such as boating, industrial operations, and wastewater discharge are major contributors. 

What Does This Mean for Marine Life? 

Microplastics can be ingested by marine organisms, including shellfish like varnish clams. These tiny plastics can accumulate in their digestive systems and potentially affect their health. Worse, when people consume these clams, they may also be ingesting microplastics. While the long-term health effects on humans are still unclear, some studies suggest potential risks such as inflammation and exposure to toxic chemicals that cling to plastic particles. 

What Can We Do About It? 

There are two main ways that we can help reduce the number and concentration of microplastics in our receiving environments: better waste management and pollution prevention. These can look like a bunch of different things but a few options are listed here:  

• Reduce plastic use: Opt for alternatives to plastic and reduce use of single-use plastic items.  
• Clothing use and washing: Reduce the use of fabrics like polyester, acrylic and nylon, and sub for natural fibers like cotton or linen and reduce the frequency of washing for materials high in plastics. Microplastic filters for washing machines also exist! You can buy one for your washing machine to filter microplastics out of your used wash water.  

• Disposal and recyling: Avoid littering and recycle whenever possible. Breakdown of plastics in the marine environment is a big contributor to microplastics pollution.  

• Support policy changes: Encourage policies that regulate plastic waste, improve wastewater treatment, and reduce industrial discharge. 

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