While media attention on microplastics has accelerated over the last few years, the scientific community has had an eye on this “emerging contaminant” for decades. In 1972, Science published a marine biologist’s observations of microplastics and research has been mounting since. Communities still have a long way to go before microplastics and their impacts are fully understood, but today’s media attention is already attracting global regulatory scrutiny.
What are microplastics?
While there is no scientifically-agreed upon definition, microplastics encompass tens of thousands of polymers and are largely categorized as being pieces of plastic less than five millimeters in length. They come from countless sources, including:
- From pressure washing structures coated in plastic-based paint
- As a byproduct of manufacturing various plastic goods
- From general wear-and-tear of synthetic products
- Through the break-down of fugitive macroplastics exposed to weather elements
Because of the number of ways microplastics can form, and due to their inherent combination of polymers, understanding related impacts and mitigation methods has proved challenging.
Where are microplastics found?
In a word? Everywhere. Some microplastics are intentionally added to consumer products in the form of microbeads, which end up in our water – most notably in ocean garbage patches. Microplastics are also found in soils and the air. Some fertilization and crop management methods have introduced microplastics into soils, and once in the soil, they can then run off into surface water bodies or seep into groundwater. Additionally, small organisms can uptake microplastics and spread the material up the food chain. There is even concern that microplastics may pick up other contaminants present in the environment and become a vehicle for entry into the food web.
Scientists have discovered microplastics are quite literally all around us, and in us – present in the air we breathe and the food we eat. For example, a subset of microplastics, called microfibers, is continually swept into the wind from sources as unsuspecting as clothing. Some scientists speculate that the largest exposure pathway for microplastics in humans is from air sources; however, human intake from drinking water and food sources is also being evaluated.
Okay, but how big is the microplastics problem?
While evidence suggests that ingested microplastics can affect organs and disrupt hormone regulation, the World Health Organization (WHO) has stated there is no current cause for concern. WHO recognizes the need for further research and has called for a reduction in plastic pollution as a way to mitigate potential human and environmental impacts. Though it is unknown whether microplastics actually pose harm to humans, they have demonstrated an ability to alter biological responses in laboratory organisms.
Water and wastewater treatment: The microplastics solution?
As a step toward reducing public concerns, WHO has pointed out that utilities may be able to leverage existing wastewater and drinking water treatment methods to address microplastics. Existing wastewater treatment methodologies generally retain macroplastics, but the degree to which microplastics are or can be retained is uncertain. That being said, wastewater treatment systems that leverage tertiary treatment techniques such as maturation ponds, filtration, and additional flocculation may be able to remove more than 90% of microplastics.
Surface water treatment systems, by design, are also capable of removing small particles such as microplastics. In a recent study, untreated tap water was shown to have higher concentrations of microplastics compared to treated water. Nanofiltration and activated carbon polishing may also provide ways to reduce the smallest of microplastic particles in finished drinking water.
Regulating microplastics: Who, what, and when
Microplastics are a global issue. As the world learns more about this contaminant and turns toward prevention and solutions, regulatory efforts are likely to accompany this focus.
- The European Union (EU) has moved forward with several national microplastics bans. In January 2019, the European Chemicals Agency (ECHA) proposed restrictions on the intentional use of microplastics. Over a 20-year period, the legislation would prevent an estimated 400,000 tons of microplastics from entering the environment. If the proposal is promulgated, it would be adopted throughout the EU in 2022.
- In the U.S., the 2015 Microbead-Free Waters Act targets a specific type of microplastic called microbeads, which for a time were commonly found in self-care products. The 2015 act prohibits the manufacturing and distribution of rinse-off cosmetics containing plastic microbeads, such as cosmetics and toothpaste.
- In 2018, California signed two bills related to microplastics. SB 1422 requires annual water testing and public disclosure of the amount of plastics found in drinking water, and SB 1263 establishes a directive for a statewide strategy geared toward learning more about microplastic risks in marine environments and developing solutions.
- The U.S. Environmental Protection Agency (EPA) supports several microplastic initiatives and hosts periodic microplastic workshops as part of its Trash-Free Waters program.
Trihydro can offer insights into several emerging contaminant concerns – microplastics included. Contact us today to learn more about the research landscape, available solutions, risk assessment, and anticipated regulatory developments.
Andrew Pawlisz, D.A.B.T.