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Microplastics

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Microplastics are synthetic solid particles or polymeric matrices that have entered our natural ecosystems. These particles possess regular or irregular shapes and range in size from 1 micrometer to 5 millimeters. They are considered water pollution because they are insoluble in water and persist in the environment for long periods. Some plastics degrade very slowly, often lasting hundreds to thousands of years. Because of this longevity, microplastics have a high probability of being ingested or accumulating in the tissues of many organisms.

Microplastic sample
Microplastic sample

Scientists classify microplastics into two distinct categories: primary and secondary. Primary microplastics are particles that are manufactured to be small, often 5.0 mm or less, before they ever enter the environment. These include microbeads used in cosmetics, plastic glitter, and microfibers from clothing. They also include plastic pellets, known as nurdles, which are used to create other plastic products. Secondary microplastics, however, are not made small on purpose. Instead, they arise from the fragmentation of larger plastic items after they have been discarded.

Photodegraded Plastic Bag
Photodegraded Plastic Bag

The process of creating secondary microplastics involves several types of degradation. Physical, biological, and photochemical degradation work together to break down large debris. A major driver is photo-oxidation, which is caused by exposure to sunlight. As sunlight, wind, and waves act on items like water bottles, fishing nets, or plastic bags, the structural integrity of the plastic weakens. This leads to fragmentation, where the large object breaks into smaller and smaller pieces. Eventually, these pieces become so small they are undetectable to the naked eye.

There are many specific ways these particles enter our world. Textiles and clothing are a massive source, accounting for approximately 35% of all ocean microplastics. This happens primarily through the erosion of synthetic materials like polyester, acrylic, or nylon during the washing process.

Snap-40
Snap-40

Another major source is tire wear. Tires contain synthetic styrene-butadiene rubber that erodes into tiny particles as they are used on roads. These particles can become dust that travels through the air. Additionally, paint is a significant source of leakage into waterways, estimated at 1.9 million metric tons per year.

Football field microplastics
Football field microplastics

The history of the term "microplastics" is closely tied to marine biology. The term is widely attributed to Professor Richard Thompson, a marine biologist at the University of Plymouth in the United Kingdom, who published a paper in 2004. However, researchers were exploring the topic as early as the late 1980s. Evidence shows the term was used in relation to marine pollution throughout the 1990s and early 2000s. Since then, the study of these particles has grown into a global scientific priority.

Nurdle signboard
Nurdle signboard

The scale of microplastic pollution is immense. In 2014, it was estimated that there are between 15 and 51 trillion individual pieces of microplastic in the world's oceans. This equates to a weight between 93,000 and 236,000 metric tons. In some areas, microplastics can contribute up to 30% of the Great Pacific Garbage Patch. In many developed countries, these tiny particles are actually a larger source of marine pollution than the visible, larger pieces of litter.

As microplastics continue to weather, they can degrade into even smaller particles called nanoplastics. Nanoplastics are a subset of microplastics that are smaller than 1 micrometer. Because they are so small, they cannot be seen by the human eye. These particles pose unique risks because they can cross cellular membranes. In fish, nanoplastics have been shown to accumulate in organs like the gallbladder, pancreas, and the brain. They may also cause interruptions in bone cell activities, leading to improper bone formation.

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🖼️ Images & Media (11)
File:Microplastics in sediments.jpg
Microplastics in sediments.jpg
Plastic straw photo-degraded and brittle.webm
File:Microplastic sample.jpg
Microplastic sample.jpg
File:Snap-40.jpg
Snap-40.jpg
File:Photodegraded Plastic Bag.jpg
Photodegraded Plastic Bag.jpg
File:Mikroplastasarp.jpg
Mikroplastasarp.jpg
File:Football field microplastics.jpg
Football field microplastics.jpg
File:Infant drinks milk from bottle.jpg
Infant drinks milk from bottle.jpg
File:Kaffe og mandarin (5198912077).jpg
Kaffe og mandarin (5198912077).jpg
File:The breakdown of a plastic bottle into smaller fragments, eventually ending up as micro- and nano-plastics.png
The breakdown of a plastic bottle into...
File:Nurdle signboard.jpg
Nurdle signboard.jpg
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