Microplastics are very small plastic particles that typically come from the breakdown of larger pieces of plastic, especially when those larger plastic pieces are exposed to environmental conditions or have been designed and manufactured for specific applications.1 There are a number of unanswered questions about microplastics, including their environmental impact and risk to human health. Regardless of their potential impacts, companies do not want their products contributing to the growing amount of microplastics being detected in the environment.
Our dependence on plastic has grown significantly (since Dustin Hoffman’s timeless scene in 1967’s The Graduate2) and is used in a wide variety of products, including overcaps and actuator buttons in aerosols and virtually every part of a pump spray. Plastics offer many functional benefits, such as strength, weight, and moldability, but, most importantly, plastics are cost-effective and often easily recyclable.
Most plastics are derived from petroleum, either directly as virgin resins or secondarily as recycled content. While most plastics are recyclable, there can be challenges in processing some plastic products. For instance, it can be challenging to separate multi-layer resin packages and, in some cases, the recycling process can degrade the quality of the resin. Additionally, not all recycling systems are equal and some may not be equipped to handle different types of plastic.
Since the cost of virgin resin is significantly lower than recycled resin, industry has continued to produce more and more plastic. However, increasing the production of virgin resin has resulted in more microplastics. The U.S., along with many other countries, has not made the proper investment in waste disposal and recycling programs to handle this amount of plastic. As a result, the U.S. was exporting waste to China, as well as other Asian countries. However, in 2017, China banned most plastic waste imports, which has significantly strained the waste disposal systems in the U.S.
Addressing our waste problem further highlights the need to monitor microplastics, which can be transported though the biosphere and enter sediment, waterways, organisms and potentially humans. Our scientific knowledge of their toxicity and impact on human health and the environment is currently limited. Despite the limited data, government and regulatory agencies continue to push microplastics policies. In an effort to increase scientific knowledge, countries and organizations around the world are studying the presence and potential impact of microplastics.
The European Chemicals Agency (ECHA) proposed to restrict the use of intentionally added microplastic particles in all consumer and professional use products,3 following the European Commission’s request to investigate the need for such a restriction.
The Science Advice for Policy by European Academics (SAPEA) published a report4 in January 2019 that claims the best available evidence suggests that microplastics do not pose a widespread risk to humans or the environment, except in small pockets. However, SAPEA did warn that the risk could change if pollution continues at its current rate.
The World Health Organization (WHO) published a study in 2019 on microplastics in water,5 concluding that the quantity and quality of data on microplastics in different types of water (marine water, fresh water, tap water and bottled water) is limited. The WHO highlighted a number of data gaps where further research is needed, but specifically emphasized the need to develop standard methods for measuring microplastic particles in water.
In Canada, Health Canada and Environment & Climate Change Canada published6 a draft science assessment of plastic pollution, which identified data gaps to guide future research and informs the decision-making on plastic pollution in Canada.
In the U.S., the California State Water Resources Control Board (SWRCB) is required to adopt a definition for microplastics in drinking water by July 1, 2020, and a standard methodology for testing drinking water for microplastics, including monitoring and reporting requirements, by July 1, 2021. HCPA submitted comments7 to SWRCB, requesting (among other things) that it be flexible with its initial definition of microplastics and consider modifying it as the science and our understanding of microplastics evolves. SWRCB must proceed as directed by the laws passed by the State’s legislature; however, more science is needed to support any policy efforts. While society may want to push forward in developing a consensus position on microplastics, we need the science to inform what issues or risks microplastics pose, if any.
Part of determining the risk of microplastics is understanding the exposure, which begins with monitoring. There have been many studies about detecting microplastics. For example, in 2019, a systematic review8 of existing literature identified 50 studies of microplastic detection in fresh water, drinking water and wastewater. The review concluded that there was a limited number of high-quality studies, and that a standard analysis of microplastics in water that can be reproduced and allow comparability is needed to conduct proper risk assessments.
Other reviews9 have noted discrepancies in comparing particle types, size and the concentration of microplastics between laboratory tests and those measured in the environment. Without a standardized method of testing, it is very challenging to assess the risk of microplastics. Beyond particle type, size and amount that exists in a source, other variables, such as the overall biodegradability of the particle, should be taken into consideration.
The science of microplastics has a long way to go before we can truly understand the potential risk that they may or may not pose to human health and the environment. In order to understand the science and establish policies, we first need a standardized testing methodology. Until then, it’s critical that policies on microplastics remain flexible to account for our evolving understanding of them. In the meantime, there is one thing we can all agree on about plastic: it needs to be properly disposed of and recycled in order to limit our overall impact on the environment. SPRAY
1 GESAMP (2016). “Sources, fate and effects of microplastics in the marine
environment: part two of a global assessment” (Kershaw, P.J., and Rochman,
2C.M., eds). (IMO/FAO/UNESCO-IOC/UNIDO/WMO/IAEA/UN/UNEP/UNDP
Joint Group of Experts on the Scientific Aspects of Marine Environmental
Protection). Rep. Stud. GESAMP No. 93, 220 link
3 Annex XV dossier can be found here
4 SAPEA’s full report can be found here
5 WHO 2019 report on microplastics in drinking water can be found here
6 Canada’s draft science assessment of plastic pollution can be found here
7 HCPA’s comments to SWCRB can be downloaded here
8 Koelmans et al. Microplastics in freshwaters and drinking water: Critical review
and assessment of data quality. Water Res. 2019 May 15; 155: 410 – 422.
9 Burns, Emily E. and Boxall, Alistair B.A. Against Adverse Impacts and Knowledge
Gaps. Environmental Toxicology and Chemistry. 2018 September 4; 9999:
1 – 21.