Microplastics in Freshwater

Microplastics in Freshwater

Plastic has become a nearly essential part of our everyday lives, from the plastic wrap around cucumbers and other food packaging to phone cases and car parts. Plastic products are used widely, with an annual output of 348 million tons, of which an estimated 8.8 million tons enters waterways and the ocean each year. For context, this is equivalent to one dump truck tipping a load into the ocean every minute of every day for each year (Parker, 2020). The continued reliance on plastic for an immense amount of consumer products, many of which are single use, results in their continual influx into aquatic environments (Li et al., 2019).

However, it is not as easy to remove the plastic from the environment as it for the plastic to reach rivers, lakes, and other waterbodies. Once exposed to the elements, plastic waste breaks down into microplastics (<5 mm in diameter) as a result of physical, photo-, and bio-degradation (Li et al., 2019). While the plastics breakdown in the natural environment, once they encounter cold, anoxic (without oxygen) conditions found in aquatic environments, their degradation slows immensely, and they can remain in the environment for centuries (Akdogan & Guven, 2019). Plastics are a genuine concern for management of the health of freshwater ecosystems due to their increasing concentrations and the impact they have on freshwater organisms (Holland et al., 2016).

Microplastics can enter aquatic environments in many different ways. The most likely source is through household sewage or industrial wastes (Akdogan & Guven, 2019). The most common form of microplastic found in the environment is the fibres released from synthetic clothing in washing machines. Research has estimated that 1,900 fibres per item may come out during washing and be released to aquatic and terrestrial environments through wastewater effluents (Browne et al., 2011 as cited in Akdogan & Guven, 2019). Another large source of microplastics is anthropogenic activities including littering and the process of waste collection and disposal. Plastic items may enter the aquatic ecosystem through wind dispersal or surface runoff and breakdown into tiny particles over time (Akdogan & Guven, 2019). It can be difficult to track where microplastics will end up as their transport is strongly influenced by wind patterns, surface runoff, and flooding, which are all variable climatic forces (Zhang, 2017).

Once the microplastics reach an aquatic environment, their fate depends upon the density, composition, and shape of the plastic. Some microplastics may sink to the ocean-floor sediment while others remain suspended in the water column and found along the shoreline. Large storm events can re-suspend dense particles, making them available for consumption by aquatic organisms, or further degradation (Anderson et al., 2016). Microplastics have been found in sediments throughout the water column, on the shoreline, and digestive systems, respiratory tracts, and tissues of aquatic organisms (Anderson et al., 2016). Research that has focused on organisms in freshwater ecosystems have found dietary plastic debris in green algae and in zooplankton (Holland et al., 2016).

In a study conducted on the Great Lakes, researchers found that 97% of 330 fish that were examined had microplastics in their digestive tracts, the majority of which were microfibres (Blok, 2021). This has consequences for fish, impacting their digestion, metabolism, growth, and brain function, but research also suggests that humans can be impacted by microplastics through the consumption of fish (Barboza et al., 2019).

As plastic is persistent in the environment and essentially never fully disappears once in the system, the best solution is to go to the source and make changes in the plastic economy. The main problem lies in the fact that 40% of the plastic manufactured today is disposable packages, designed for a single use (Parker, 2020). Plastic waste could be significantly reduced by improving waste collection and recycling, rethinking product packaging, moving away from unrecyclable plastics, expanding the use of refillable containers, and potentially using other materials in some cases (Parker, 2020).

While this seems like a daunting task, there are ways to address the issue locally. Many stewardship groups organize shoreline cleanup events throughout the summer and they are often looking for additional volunteers. Some groups, such as the Friends of Kootenay Lake Stewardship Society, also organize lakebed cleanups where divers remove waste from the bottom of the lake (Metcalfe, 2021). Reach out to a local group to get involved or contact the BCLSS office and we can connect you with someone in your area.

Additionally, raising awareness about this issue and bringing it to the attention of policy makers has the potential to shift legislation around the use of single-use plastics and assist in the implementation of new recycling practices as we have seen at both the provincial and federal level. The Canadian federal government is currently in the process of implementing a ban on non-essential single use plastics. This is being done by amending the Environmental Protection Act, 1999, to identify plastic as toxic. This will allow the federal government to impose risk management measures to prevent plastic pollution (Welsh & Dick, 2021). The BC government is also working on updating legislation to identify and take direct action to phase out single use plastic (Ministry of Environment and Climate Change Strategy, 2021). While this issue is complex and needs to be addressed at the industry level, small steps implemented in communities have the potential to have great influence and with continued pressure, legislation can be implemented and amended in order to improve the environment for all.


Akdogan, Z., & Guven, B. (2019). Microplastics in the environment: A critical review of current understanding and identification of future research needs. Environmental Pollution, 254, 113011. https://bit.ly/3qpG4dL 

Anderson, J. C., Park, B. J., & Palace, V. P. (2016). Microplastics in aquatic environments: implications for Canadian ecosystems. Environmental Pollution, 218, 269-280. https://bit.ly/3koD4ui

Barboza, L. G. A., Lopes, C., Oliveira, P., Bessa, F., Otero, V., Henriques, B., Raimundo, J., Caetano, M., Vale, C., & Guilhermino, L. (2020). Microplastics in wild fish from North East Atlantic Ocean and its potential for causing neurotoxic effects, lipid oxidative damage, and human health risks associated with ingestion exposure. Science of the total environment, 717, 134625. https://bit.ly/3HcPFL5

Blok, A. (2021). Microplastics and algae tangle in the Great Lakes. Environmental Health News. https://bit.ly/3n5FrnL

Holland, E. R., Mallory, M. L., & Shutler, D. (2016). Plastics and other anthropogenic debris in freshwater birds from Canada. Science of the Total Environment, 571, 251-258. https://bit.ly/3qlydOq

Li, C., Busquets, R., & Campos, L. C. (2020). Assessment of microplastics in freshwater systems: A review. Science of the Total Environment, 707, 135578. https://bit.ly/3oebZLD

Metcalfe, B. (2021). Divers pull garbage from floor of Kootenay Lake in annual lakebed cleanup. Nelson Star. https://bit.ly/3oh85Bz 

Ministry of Environment and Climate Change Strategy (2021). Province takes aim at banning problem plastics. BC Gov News. https://bit.ly/3FyXs3Y

Parker, L. (2020). Plastic pollution is a huge problem—and it’s not too late to fix it. National Geographic. https://on.natgeo.com/3mZSEOO

Welsh, P. & Dick, M. (2021). Canada: Federal Plastics Ban. Osler, Hoskin & Harcourt LLP. https://bit.ly/3CCZT3E

Zhang, H. (2017). Transport of microplastics in coastal seas. Estuarine, Coastal and Shelf Science, 199, 74-86. https://bit.ly/3n3COCU

Author: Marie McCallum

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