According to the U.S. National Oceanic and Atmospheric Administration (NOAA), microplastics are plastic fragments less than 5 millimeters in length. In the last decade, microplastics have emerged as a field of study dedicated to the preservation of the Earth’s oceans. Plastic is the most prevalent example of debris in our oceans, and microplastics in particular are difficult to deal with since they can easily pass through water filtration systems.
Despite the relative recency of research into microplastics and their impacts, their first appearance was about fifty years ago in cosmetic products like toothpaste and cleansers. Since then, the number of products containing microplastics has increased greatly, resulting in two broad categorizations: primary and secondary.
Primary MPs are purposefully manufactured and are normally present in either cosmetic products or air blasting technology. Microplastic “scrubbers” have replaced natural ingredients in many facial cleansers and scrubs due to their exfoliating properties. Air blasting, the process by which rust and paint are removed from machinery, engines, and boat hulls, entails shooting acrylic, melamine, or polyester MPs at the area in question. An unfortunate side-effect of this process is that the MPs often become contaminated with heavy metals such as cadmium, chromium, and lead upon continual reuse, which only further damages marine flora and fauna.
Secondary MPs, on the other hand, are derived from the breakdown of larger plastics; over time, a combination of various kinds of environmental degradation can reduce the structural integrity of plastic, causing it to break down into smaller, microscopic pieces through a process known as fragmentation. The uneven shapes of MPs observed in the environment lend validity to fragmentation being a key source.
Although data on the negative consequences of MP pollution is mixed, mounting evidence shows that if MP pollution continues at the same rate, we could see widespread consequences, especially for marine life. The main sources of information that researchers have drawn from in their investigation of the impact of microplastics are the occurrence of microplastics in the marine environment, their residence time, and their documented ingestion by marine animals. From these sources of information, scientists have extrapolated a variety of current and potential effects, with the most significant being integration into biological organisms. Microplastics can become embedded into animals’ organs through either respiration or ingestion, putting nearly all marine wildlife at risk. Many crustaceans and other similar species have been found to have microplastics in their gastrointestinal tract, likely due to having mistaken the plastics for food, which can be extremely damaging to the animals by blocking their intestinal tract. Bottom feeders such as sea cucumbers are especially at risk due to their indiscriminate feeding habits and the fact that microplastics often settle at the seafloor. Furthermore, primary reef-builders called Sceleractinian corals have been observed absorbing MPs in laboratory conditions, which has caused them to become stressed and bleached. Coral reefs are essential for the marine ecosystem since they supply a food source for millions of creatures, protect coastlines from storms, provide a habitat for many species, etc.
Even humans are not spared from the effects of microplastics; consuming contaminated seafood or seafood packaging, inhaling contaminated air, or drinking contaminated water can all result in the ingestion and accumulation of microplastics. A variety of debilitating effects such as hypersensitivity or unwanted immune response can result in humans. However, the primary concern with human health is not the microplastics themselves, but rather the carcinogenic chemicals they are made of and the pathogens and heavy metals the MPs can absorb. Ultimately, MPs are not solely an “environmental” issue since the effects can very easily spill over to humans if left unchecked.
Despite the difficulty of dealing with microplastics, scientists do have possible solutions. The first solution is to educate the public through recycling campaigns, a tried-and-true strategy of reducing plastic waste and hopefully by extension microplastics. Other more high-tech solutions for managing MP pollution include plastic incineration and biodegradation. Incineration involves combusting certain plastics to generate energy, offering an MP-free way to manage plastic waste while contributing to our energy needs. Biodegradation, or the use of enzymes to break down plastics into usable materials, is particularly well suited to decrease microplastic waste because it is effective regardless of the size of the plastic. For example, these enzymes could be used to treat wastewater, which would greatly decrease the number of MPs that would end up in the environment.
Overall, though microplastics present many of the same threats as macroplastics, their small size makes them much more difficult to remove from the environment once they are already embedded. Although right now some of the more harmful effects may not be tangible, if we allow a steady accumulation of microplastics in the environment, the resulting consequences could harm the marine ecosystem and humans for generations to come.
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