Every year, an estimated 8 million tonnes of plastic enter the ocean. Much of it breaks down into tiny fragments less than 5mm in size — microplastics. But they don't disappear. They persist for hundreds of years, accumulating in every corner of the marine environment.
What Are Microplastics?
Microplastics come in two forms. Primary microplastics are manufactured small — think microbeads in cosmetics or plastic pellets used in manufacturing. Secondary microplastics result from larger plastic items breaking down through UV radiation, wave action, and weathering.
A single fleece jacket can shed up to 250,000 microplastic fibres in one wash. A car tyre releases microplastic particles with every kilometre driven. Even tea bags and disposable face masks contribute.
The Scale of the Problem
Microplastics have been found in the Mariana Trench, 11km below the surface. They're in Arctic sea ice, Antarctic snow, and on the summit of Mount Everest. A 2023 study estimated there are over 170 trillion microplastic particles floating in the world's oceans.
Impact on Marine Life
Marine organisms from zooplankton to whales ingest microplastics. Filter feeders like mussels and oysters are particularly affected. The plastics themselves can cause physical harm, but they also act as vectors for other pollutants — absorbing chemicals like PCBs and pesticides from the water and delivering concentrated doses to the animals that eat them.
Coral reefs are affected too. Research shows corals actively ingest microplastics, which can cause tissue damage and reduce their ability to photosynthesize.
Microplastics and Human Health
We eat, drink, and breathe microplastics daily. Studies have found them in human blood, lungs, liver, and placenta. The long-term health implications are still being researched, but early evidence suggests potential links to inflammation, cellular damage, and disruption of the gut microbiome.
Solutions
Reducing plastic production is the most effective strategy. Supporting extended producer responsibility legislation, choosing natural materials, using microplastic-catching laundry bags, and properly disposing of waste all help. But systemic change — not just individual action — is what's needed most.
This article is part of the CONTRAST project, funded by the European Union under Horizon Europe. Views expressed are those of the author(s) only.