By Eden Hataley, Dimple Roy, and Chelsea Rochman

At the opening of the 77th session of the UN General Assembly (UNGA), UNGA President Csaba Kőrösi highlighted the importance of addressing today’s challenges by identifying “Solutions through Solidarity, Sustainability, and Science” – the motto of his Presidency. The first meeting of the Intergovernmental Negotiating Committee (Plastic Pollution INC-1) – the group tasked with negotiating and drafting, by 2024, an international, legally binding agreement to end plastic pollution – presents an opportunity to do just that.

During this inaugural event, and as the global community prepares to bring strategies to prevent and mitigate plastic pollution to the table, we must remember to stretch our thinking beyond the visually compelling marine macroplastic pollution and also incorporate actions that 1) encompass microplastics and 2) address plastics emissions to freshwater environments – two essential components of the problem. After all, measures that reduce macroplastics will not address all types of microplastics (e.g., pre-production plastic pellets from industry or microfibers from textiles), and actions applicable to the ocean may not be relevant to rivers and lakes.

Why are microplastics important?

The Organisation for Economic Co-operation and Development (OECD) estimates that in 2019, 22 million tonnes of plastic leaked into the environment globally, a value predicted to double by 2060. Macroplastics, or pieces of plastic greater than 5 millimeters (mm) in size (e.g., checkout bags and straws), account for 88% of this leakage, whereas microplastics, or plastic particles less than 5 mm in size, account for 12%.

Although when we think of microplastics, we often think of microbeads in personal care and cleaning products, the term incorporates many types of microplastics that differ in their polymer makeup, associated chemicals, size, shape, and, importantly, where they come from, also referred to as their source. These include microplastics intentionally produced to be so small (primary microplastics, such as microbeads and pre-production plastic pellets) and microplastics that result from the degradation of larger plastic items (secondary microplastics, such as fragments of large plastic debris, tire and road wear particles, paint, and microfibers).  

Researchers have found microplastics in terrestrial, aquatic, and atmospheric environments worldwide. The ubiquity of microplastics has led to the contamination of hundreds of species of wildlife across all levels of the food web. This is especially concerning as research shows that microplastics can be harmful to organisms due to their chemical components and because they can physically replace food but provide no nutritional value and move into cells and tissues. And although we do not yet fully understand how microplastics impact human health, they have also been found in the food and water we consume.

Why are freshwater environments important?

The OECD further estimates that in 2019, around 32% of the 22 million tonnes of leaked plastic ended up in aquatic environments, the rest accumulating in terrestrial environments. Notably, the bulk of this 32% is understood to have ended up in freshwater environments. The OECD estimates that between 1970 and 2019, 109 million tonnes of plastic accumulated in rivers and lakes globally – nearly four times the amount accrued in the marine environment (30 million tonnes). These numbers clearly show that freshwater environments act not only as a source of plastic to the world’s oceans but also as a sink, accumulating plastic from many sources. This is concerning because healthy freshwater ecosystems play an integral role in sustaining life (e.g., are a critical source of drinking water as well as a biodiversity hotspot) and are already among the world’s most degraded and threatened ecosystems.  

How can we include microplastics and freshwater emissions in the global agreement?

Regarding microplastics, strategies that address macroplastic pollution will indeed tackle some secondary microplastics, like those resulting from the fragmentation of large plastic debris. But these same strategies are unlikely to adequately address other types of secondary microplastics (e.g., tire and road wear particles, paint, or microfibers) or primary microplastics (e.g., microbeads and pre-production plastic pellets). Therefore, in the global agreement, in addition to approaches geared toward large plastic debris, we must include measures that specifically target the emission of microplastics.

Accordingly, one of the actions under strategic goal 4 outlined by the UN Environment Programme (UNEP) in the brief on plastics science (UNEP/PP/INC.1/7), issued in preparation for the INC’s first meeting, is “prevent microplastics leakage.” These measures could include, for example, banning problematic or unnecessary microplastics (e.g., microbeads), introducing regulations to trap microplastics at their source (e.g., tire and road wear particles, microfibers, and pre-production plastic pellets), or setting emissions standards for microplastics in stormwater and wastewater.

Regarding fresh water, first and foremost, the global agreement needs to recognize that freshwater systems are highly contaminated with plastics. And given this, the agreement must incorporate plastic pollution prevention and mitigation strategies as well as clean-up initiatives at the scale of rivers and lakes. It is noteworthy that the brief on plastics science, mentions the word “marine” 62 times, whereas “freshwater” appears a meager three times. Putting forth a greater effort to address the problem upstream in fresh water will not only help us reduce the accumulation of plastic in these environments, but also prevent the transport of this plastic to oceans by way of rivers.

Ultimately, acting comprehensively on the problem of plastic pollution by tackling microplastics and macroplastics as well as plastics emissions to rivers, lakes, and oceans will contribute to SDGs 12 (responsible consumption and production) and 14 (life below water), as well as SDG 3 (good health and well-being).

Eden Hataley is a Ph.D. student, Department of Physical & Environmental Sciences, University of Toronto Scarborough. Dimple Roy is Director, Water Management, IISD. Chelsea Rochman is Assistant Professor, Department of Ecology & Evolutionary Biology, University of Toronto.