Microplastics! What are They, and Why are They Harmful?

Microplastics, or polymer chains composed of carbon and hydrogen atoms, are much smaller pieces of plastic that have disintegrated from larger plastic over time and environmental impact. Although it takes thousands of years for plastic to completely break down, the sun’s UV radiation and the abrasive ocean waves and waterways help to break plastic down into smaller pieces much earlier than that. These smaller pieces of plastic, or microplastics, must be five millimeters (0.2. in) in diameter to be considered microplastics. Plastic makes up the bulk of water pollution throughout the oceans and Great Lakes in the world.

There are two categories of microplastics: primary and secondary. Primary microplastics are composed of commercial plastics, such as microbeads, very tiny pieces of manufactured polyethylene plastic that are used in exfoliants of health and beauty products, such as some cleansers and toothpaste, plastic pellets, from industrial manufacturing, and plastic fibers, such as nylon in fishing netting. Secondary microplastics come from larger plastic household items, such as plastic water bottles.

Surprising ways in which plastic enters waterways and oceans:

1. Personal Use

When we throw plastic away, it goes to a landfill, but before it gets to a landfill, some trash is blown away because it’s so lightweight. It gathers around drains and gutters where it will eventually enter the waterways. It’s important for us to be as mindful as possible about our plastic use and think of ways to replace our plastic with sustainable and recyclable options, like reusable shopping bags at the grocery store.

2. Littering

Rainwater carries litter to the oceans and lakes through waterways. It’s important to always seek out trash cans and recycling units to deposit trash and recyclables rather than leaving it on the ground and other places where it could end up in nature and in the water supply.

3. Down the Drain

Anything that goes down the drain will eventually end up in the ocean.  Microbeads can easily pass through water filtration systems and end up in the ocean and Great Lakes, posing a potential threat to aquatic life. According to the United Nations Environment Programme, fifty years ago was when plastic microbeads first appeared in personal care products, with plastics replacing natural ingredients. However big the problem of microbeads is, little has been known to the consumer.  On December 28, 2015, President Obama signed the Microbead-Free Waters Act of 2015, banning plastic microbeads in cosmetics and personal care products. Microsynthetics are even released into waterways when we wash our clothes in the washing machine because they cannot be filtered by wastewater plants.

4. Manufacture Runoff or Spillage

We’ve all seen videos and photographs, both in films and real life, of pollutive waste being dumped from a pipe into a small body of water next to a production plant, and we’ve seen other spills, like oil spills from large ships or even spills from construction vehicles on the road, all of which bear a negative impact to the environment. Each of these situations are preventable, and while measures are likely being taken to secure these vehicles, containers, and waste products, more can be done to ensure that they are properly disposed of to lead to the damage possible.

How this Affects Marine Life

Microplastics have become part of the ocean’s ecosystem. They float along the waterways, oceans, and lakes until something causes them to sink deeper into the water. There are three ways that this happens.

1. Biofouling

That is when microorganisms, plants, algae or animals connect to a piece of plastic, colonize on it, and this allows the microplastic’s density to sink to the bottom of the ocean. Scientists have found 10,000 times more microplastics on the seafloor than in contaminated surface waters.

2. Food Chain

As of 2018, more than 114 aquatic species in marine and freshwater ecosystems had been found to contain microplastics, from zooplankton to seabirds. Various invertebrate sea animals, including crabs, have been found to have microplastics stuck in their digestive tracts and tissues. The microplastics break down to the same size as prey for many marine species, so there is always the possibility they will confuse the microplastics with food and ingest it. Then one marine life with a digestive tract full of microplastics is eaten by another marine life, and the microplastics move up in the food chain.

3. Poop

If an animal can excrete the plastic, the plastic will continue its journey to the bottom of the ocean, where marine life that feed on feces will eat it.

Microplastics in the Marine Life Diet

Eating microplastics can be harmful for marine life. It can cause a reduced consumption of edible, nutritious food, decreased energy levels, and possible toxicity. Additionally, other water pollutants often mix with microplastics, increasing toxicity in marine life. Considered as a potential global threat to marine ecosystems, microplastics’ biological mechanisms determining their impact on marine life are still largely unknown. Corals, for example, when exposed to microplastics, preferentially ingest polypropylene, which results in several anomalies from feeding impairment to mucus production and altered gene expression. The coral’s microbiome can be altered directly and indirectly because of microplastics, causing tissue abrasions that result in an overabundance of opportunistic bacteria.

Plasticosis is a recently discovered condition characterized by fibrosis, mostly found in seabirds. It’s because of the overconsumption of plastic. This disorder results in significant gastrointestinal harm, including inflammation, fibrosis, and scarring in the digestive system, which negatively affects the bird by making it hard to process food and receive nutrients.

Besides the toxicity that marine life is at risk for by consuming microplastics, they also face the risk of becoming tangled in microplastics, like fishing netting. This can cause great harm or death. Of course, plastic, like the well-known straw, affects marine animals like turtles.  Microplastics continue up the food chain with the consumption of marine life by humans, increasing our risk of toxicity and harm.

Microplastics are considered a major threat to the ecosystem. They come from places, such as, commercial plastic and household trash. Every time plastic isn’t recycled, there is the risk of it ending up in the oceans or Great Lakes. Once in the water, microplastics cause great harm to marine life, including plants and animals. The total impact of the harm of these microplastics is still not completely understood.  The NOAA Marine Debris Program is leading efforts within NOAA to research this topic. The first step in determining the impact of microplastics on the water’s ecosystem is to able to make a global comparison of the distribution of microplastics. To do this, NOAA is working on creating field and laboratory methods that will test the sand, sediment, and surface water microplastics. The only way to end this pollution is to better understand it’s impact on us.

Plastic is not going anywhere,  anytime soon, so think twice before putting that plastic bottle in the trash can. Lit Shark is committed to further discussing these issues and seeking out practical solutions for improving these problems.