Microplastics

Increasingly, the use and fate of plastic materials is coming under scrutiny by government environmental agencies and academic researchers around the world. This is due in large part to the widespread and highly visible problem of how to manage the large volume of discarded plastic containers and packaging products that end up in the waste stream.

These highly visible discarded materials in the environment are known as “macroplastic” wastes. Policymakers around the globe are struggling to apply waste management principles, specifically stimulating efforts to “reduce, re-use and recycle” these materials, and meaningful waste management collaborations by diverse stakeholders are emerging. Given the widespread and visible nature of this waste problem, these efforts are welcome, and all parties are hopeful, that a broad, long-lasting solution can be established.

Environmental researchers are focusing efforts on new categories of waste found in the environment, in some cases arising from use of a variety of plastic materials in formulations for consumer and industrial products. The first major category is the so-called “primary microplastics” which refer to intentionally-added materials such as “micro-beads” or “microfibers” that provide certain desirable performance properties but without any attendant release to the environment as they become embedded in the applied paint film.

The other major category is known as “secondary microplastics”, which have yet to be formally defined, but can best be described as the “polymeric fragments” released into the environment over time from plastic-containing products, largely through the degradation of larger (i.e. macroplastic) materials. These secondary microplastics include releases from synthetic fibres in clothing (primarily from the laundering process), weathering of macroplastic wastes, degradation of polymeric surfaces (like paint) on exterior substrates, and wastewater streams that may receive discharges and/or releases of secondary microplastics from all sources.

Numerous studies on the environmental prevalence and fate of secondary microplastics have been published, but differ widely in how they have collected, characterized and quantified the sources and pathways of secondary microplastic releases. Accordingly, there is little consensus on which products are the more prevalent or likely contributors and their relative impact, if any, on the marine ecosystems.

Despite these uncertainties in the underlying studies, many media outlets and advocacy organizations have drawn attention to the issue of secondary microplastics in the marine environment. These reports do not often cite the scientific uncertainties associated with the underlying findings and have led to widespread confusion regarding the nature of the problem, including potential sources and pathways for the presence of microplastics in the environment.

In contrast, other uses of microbeads in personal care products and cosmetics eventually result in them being “washed off” and discharged into the environment, either directly or indirectly through wastewater treatment systems. As a result, marine pollution prevention concerns have led several governments to enact regulations for use in personal care products.