The world produces around 430 million
metric tons (t) of plastic a year, according to the United Nations. That's the weight of almost
1,300 Empire State Buildings. Without a binding treaty to limit plastic production, the number is on
track to more than double by 2050. In that same period,
mismanaged plastic waste is expected
to double, reaching over 120 million t.
Images of plastic bottles washed up on beaches and six-pack rings choking marine animals have become
symbols of plastic pollution. In this issue, C&EN takes a deep dive into the less visible, insidious
side of our plastics problem: microplastics.
As the name implies, microplastics are tiny particles—specifically designated as less than 5 mm in size.
Some are purposefully made small for use in products like cosmetics, where they can serve as exfoliants.
Most result from the disintegration of larger plastic items. Microplastic is a relatively new
term in the vernacular, coined 20 years ago. And research on microplastics and even smaller
particles—nanoplastics, which are smaller than 1 µm—has boomed in the past decade.
Scientists have quickly found the particles everywhere: in our land, water, food, bodies, and air. Micro-
and nanoplastics have been discovered in the clouds above Mount Fuji, in the Mariana
Trench—the deepest point on Earth—and in Arctic ice. They have been detected in nearly every part of the
human body. In October, researchers reported finding microplastics
in dolphin breath.
Growing interest
Increasing awareness of and concern about microplastics have led to a surge in research on
these persistent plastic particles in the past decade.
Publications mentioning microplastics or nanoplastics, per a Scopus searcha
Sources: Scopus, C&EN analysis.
a Scopus includes papers from over 7,000 publishers worldwide.
The problem with microplastics, as with petroleum-derived plastics of any size, is that they take
hundreds of years to decompose. Their small size means they travel easily, making them pervasive. Some researchers believe that
microplastics might be affecting the climate to an extent,
and studies have found that microplastics are altering agricultural land. These plastic bits can contain
a slew of chemicals, many of them toxic. The PlastChem project, run by an international team of
scientists, has found more than 16,000 chemicals in
plastics, around a quarter of which are hazardous.
In addition to containing these chemicals, plastic microparticles can also bind with harmful pollutants
in water and soil before being ingested. They have been shown to make corals and marine animals more
susceptible to diseases. Scientists are still unraveling the fate of these tiny particles and the threat
they pose to human health and the environment.
In the following pages, we present what researchers know today. We look at the many ways microplastics
permeate our world and how they might be harming our health. We also visit the latest efforts to combat
microplastic pollution, both at the beginning of plastics' lives via biobased and biodegradable
feedstocks, and at the end of their lives through the use of polymer-degrading enzymes.
Microplastics are not a new problem. But scientists are just beginning to understand their behavior and
properties. By putting a spotlight on them, we hope to inspire more conversation about their risks, the
research gaps, and how best to shape regulation.
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