What are Microplastics?

microplastic header

When we think about plastic pollution, we often think about the plastics we can see: plastic grocery bags, plastic bottles, and various other discarded plastics that make their way into our rivers and waterways. Unfortunately, plastic pollution is much more extensive than we previously thought and can actually occur at an incredibly small scale known as microplastics!   

These tiny plastic particles, less than 5 millimeters (.19 inches) in size or smaller than a grain of rice, are making their way into our rivers and having an extensive environmental impact. 

Understanding the sources, effects, and potential solutions to this problem is crucial for protecting our water bodies and the myriad of life forms that depend on them.

Photo: Alexander Kung (Microplastic Research in Taiwan)

Sources of Microplastics in Rivers

Microplastics in rivers originate from various sources:

Primary Microplastics: These are intentionally manufactured small plastic pellets used as raw materials in the production of plastic products. They often enter rivers through industrial runoff and accidental spills during transportation and handling. 

Secondary Microplastics: These result from the breakdown of larger plastic debris due to weathering, UV radiation, and mechanical forces. Everyday items like plastic bags, bottles, and packaging materials degrade over time, contributing significantly to microplastic pollution in rivers. 

Personal Care Products: It may come as a shock to learn that some personal care items, such as exfoliating scrubs and even toothpaste, contain microbeads—tiny plastic particles designed for abrasiveness. These microbeads easily pass through wastewater treatment plants and end up in rivers. 

Textile Fibers: Synthetic fabrics shed microfibers during washing or even being tossed out like litter. These tiny fibers escape through sewage systems and find their way into rivers. 

Sources of Microplastics in Rivers

When plastic pollution enters the river (1), it can begin to fragment into smaller pieces (2). This is where fish begin to mistake these microplastic fragments for food (3). As larger fish consume the smaller fish (4) the microplastics begin making their way up the food chain (5-6).

Thus, the presence of microplastics in river systems has far-reaching consequences:

Image: Shutterstock
  • Water Quality: Microplastics act as carriers for pollutants, such as heavy metals and bacteria, which adhere to their surfaces. These pollutants contribute to poor water quality and degrade wildlife habitat. 
  • Aquatic Life: Fish and other aquatic organisms often mistake microplastics for food. Ingesting these particles can lead to physical blockages, reduced feeding efficiency, and exposure to toxic substances. Microplastics can also cause entanglement and physical injuries to aquatic animals. 
  • Food Chain Contamination: The ingestion of microplastics by smaller organisms results in bioaccumulation – these microplastic particles slowly accumulate in an organism over time causing them to become more concentrated the higher up the food chain they persist. This means that predators, including large fish, birds of prey and even humans who consume fish and shellfish, are also at risk of ingesting microplastics and associated toxins. 
  • River Health: Microplastics can disrupt the natural processes of rivers, such as sediment transport and nutrient cycling, leading to long-term ecological imbalances. 

So...what can be done?

Addressing microplastic pollution in rivers requires a multidisciplinary approach:

  • Policy and Legislation: Reduce dependency on single-use plastics. Promote recycling programs and their ease of access. Regular street cleaning can reduce the amount of stormwater runoff carrying plastic contaminants to our rivers during rain storms.  
  • Science & Restoration: The science community is working diligently to try and learn more about the extent and severity of microplastic pollution such as: What are the most common sources of microplastics? Where do they accumulate? What are the long-term health implications for humans and wildlife? 
  • Community Engagement: Public participation in river clean-up activities, educational programs, and advocacy for plastic reduction can significantly impact reducing microplastic pollution. As well, understanding your own impact and what changes you can make for yourself goes a long way!

Microplastic pollution in rivers is a pressing environmental issue that demands our attention. By understanding the sources and impacts of microplastics, and by implementing effective mitigation strategies, we can protect our rivers and ensure the health of both aquatic ecosystems and human populations.

Each small action towards reducing plastic use and improving waste management can contribute to a cleaner, healthier future for our rivers and all those who rely on them.