Microplastics: Processes and Byproducts

Plastic has been a concern of environmentalists for many years. Synthetic polymers are not biodegradable, and therefore continue to exist in nature after being discarded. This leads to a build-up of plastic with no place to store it. Microplastics are found in the soil, air, and ocean. Microplastics that are found in the soil become part of runoff after rain. This deposits the microplastics in a river, which eventually opens up into the ocean. Therefore the majority of microplastics end up in either the air or the ocean. One way that microplastics harm the environment is by sitting in the ocean. Most plastics contain chemicals called plasticizers, that allow rigid plastics to have some flexibility. Plasticizers, however, are very toxic. One very toxic plasticizer is dibutyl phthalate (C₁₆H₂₂O₄), which was used in polyvinyl chloride ((C₂H₃Cl)ₙ) for almost 40 years before it was banned in 2008. When floating in the ocean, these microplastics leech plasticizers into the ocean, which then join the ecosystems of the animals that people eat. Therefore, most people are consuming small amounts of plasticizer in their daily life.

Another reason why microplastic pollution is concerning is that microplastics can act as absorbing materials. Plastics can absorb persistent organic pollutants (POPs), which can be toxic. However, the absorption rate of POPs by microplastics is much higher, because they have a much larger surface area to volume ratio. Additionally, These microplastics can be ingested by fish and other marine life. These pollutants then enter the digestive systems of these fish, and eventually many other species that eat the contaminated fish, including humans. Additionally, the ingestion of microplastics by fish is detrimental to the maintenance of marine ecosystems because the solid plastic remains in the stomach of the fish after ingested. This leads the fish to starve, as it cannot digest the plastics. All of these marine consequences of microplastic contamination are threatening to the environment. Although almost all microplastics are filtered out of water during primary and secondary water treatment, the sludge that is the byproduct of such sewage treatment is often used as fertilizer. The microplastics that are caught during this process, are then reintroduced into the soil, which eventually distributes them all throughout the environment. This creates contaminated water that affects all of society. Another way in which water is contaminated is through the filtering and bottling processes of bottled water. The average bottle of water contains 325 polymer particles/liter. Thus, the water that we drink is contaminated with microplastics as well. Even tap water contains microplastics. Tap water in New York contains around 150 polymer particles/liter. An additional source of microplastic contamination is through the air. Microfibers are present in the air from laundering clothing. These particles are then inhaled by humans and animals. These microscopic particles collect in the lungs, and could lead to health problems in the future. Among all of these toxic consequences of microplastics, microplastics also litter beaches and roads throughout the world. They are adding to the pollution of the world’s natural resources, and the preservation of the earth.

Microplastics

Environmental Pollution

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