According to a 2019 study, an average person could be ingesting as many as 1,900 microplastic particles a week, which is equivalent to eating a credit card. But how does all this plastic get into our bodies, and what can we do about it?
In a study commissioned by the World Wide Fund for Nature (WWF), researchers at the University of Newcastle analyzed data from 50 studies to estimate the quantity of microplastics ingested by human beings and found that globally, the microplastic consumption per person is over 250 grams per year.
The first question to ask is what microplastics are. The US National Ocean Service defines microplastics as “small plastic pieces less than five millimeters long”. Microplastics can be primary or secondary. Primary microplastics are plastics that are intentionally designed to be small, such as microbeads. Microbeads are used as ingredients in cosmetic and personal care products (PCCPs) due to the wide variety of purposes they can serve and their relatively low cost. Even though research on and awareness of microplastics does not have a long history, the issue itself does, with the first microbeads appearing in PCCPs about 50 years ago.
The percentage of microbeads and other microplastic components in PCCPs can vary from less than 1% to more than 90%. For an illustrative example, the microplastic content of an exfoliating shower gel can be equivalent to the plastic used for its packaging. Moreover, while the packaging can be recycled, the microplastic components cannot be. In the case of leave-on products, they directly enter our bodies. In the case of rinse-off products, they get into sewage, which may end up in water and soil through the dumping of sewage sludge in water bodies or landfills and wastewater irrigation. This problem cannot be fully solved by standard water treatment facilities because, due to the imperfections in these systems, a portion of microplastics remain in the treated water.
It’s not only cosmetic and personal care products that contain primary microplastics. Plastic fibers in synthetic textiles such as nylon are composed of primary microplastics which are released into wastewater every time an item containing synthetic fabrics is washed. According to a report published by the International Union for Conservation of Nature and Natural Resources in 2017, microplastics released from textiles washed make up about 35% of all microplastics released into oceans globally.
Another source of primary microplastic pollution is plastic pellets, which are plastic masses about the size of lentils. Also known as pre-production pellets or nurdles, plastic pellets are produced by petrochemical companies and then melted down for the production of a final product in plastic manufacturing facilities. The issue is that these pellets can escape into the environment in the transportation phase or during production processes, polluting waters and soils.
Meanwhile, secondary microplastics are formed when larger plastics are broken up into small particles due to factors such as heat, waves, winds, and ultraviolet radiation. Single-use plastics, such as plastic straws, are the main source of secondary plastics in the environment.
Microplastics that enter water bodies are consumed by marine organisms. For instance, they mistake plastic pellets for food due to their similarity to fish eggs. While microplastics in soil is a less investigated topic compared to microplastics in water, existing evidence suggests that microplastics can accumulate in yeasts and filamentous fungi, leading to a potential accumulation or magnification of microplastics in the soil food web. This microplastic contamination in water and soil eventually makes its way to our food chain. So far, microplastics have been detected in commodities such as seafood, honey, salt, soft drinks, milk, and beer. While the effects of microplastic ingestion on human health are still unknown, it is hypothesized that the accumulation of microplastics in the human body may lead to toxic effects such as immune system disruption.
While you can reduce your microplastic intake to a certain extent with small lifestyle changes such as relying less on bottled water, reducing your use of plastic food containers, and eating less of foods wrapped in plastic, a significant reduction will most likely require collective action and prioritization of the issue by the world’s governments.