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The Tennessee River is the 5th largest river in North America and flows through three southeastern states: Tennessee, Alabama, and Kentucky. On its journey north through Kentucky, the Tennessee River meets the Ohio River before merging with the Mississippi and eventually emptying into the Gulf of Mexico. Unfortunately, this river has been subject to mass pollution. Although the state of the river’s quality has improved since the passing of the Clean Water Act in the 70s, in 2010, 32.4% of the river was found to be impaired, or unable to support one of its uses including wildlife habitats, recreation, fishing, and drinking. By 2020, after only a decade, that figure worsened to 55.4%.

The Southeast is home to over three-fourths of all freshwater fish species found in the United States and Canada. The Tennessee River is home to over 300 identified native fish species and 125 varieties of mussels and hosts around three-quarters of all native species of fish in the United States. Biologists often refer to the region as an “underwater rainforest” due to the staggering biological diversity present. However, the pollution level in the Tennessee River and its tributaries poses a serious threat to its inhabitants, many of which are found nowhere else in the world. Out of any of the large basins in North America, the Tennessee River Basin has the highest number of imperiled species. 

  Pollutants from households and industrial companies can also find their way into freshwater environments through runoff. Stormwater runoff can pick up pollutants such as pesticides or fertilizers and then enter storm drains or the river directly. Household chemicals- such as common cleaning agents-can be washed down drains or off lawns and enter the Tennessee River through drainage systems. In addition, antibiotics can enter the river from pharmaceutical plants or people attempting to dispose of them by flushing them down the toilet. Instances such as these where harmful compounds enter the Tennessee River can cause irrevocable damage to threatened species and encourage eutrophication in the Gulf of Mexico, in which algae proliferate from excess nutrients.

Microplastics are plastic particles or microfibers smaller than the size of a pencil eraser and are present in manufactured foods, clothing, and other products. They are classified into two subcategories: primary and secondary microplastics. Primary microplastics enter the environment directly and can include products such as microbeads or synthetic fibers. Secondary microplastics are the product of the breaking down of larger plastics through weathering. In a study performed by Dr. Andreas Fath in 2017, the Tennessee River was found to have between 16,000 and 18,000 microplastic particles per cubic meter of water. For scale, that is 8,000% higher than what Fath found in a previous study of the Rhine River in Germany. He largely attributes this to the presence of plastic waste in landfills- unlike the US, Germany collects its plastic waste separately and then exports, recycles, or combusts it.

So, why is there so much microplastic pollution in the Tennessee River? Plastic bottles, shopping bags, Styrofoam, plastic straws, and microbeads found in cosmetic products are some of the biggest culprits. Discarded plastic waste from roadsides, urban areas, or landfills can easily wash into our waterways, contaminating both wildlife habitats and our own drinking water. Many fabrics contain plastic microfibers that can be shed into laundry wastewater. These plastics take hundreds of years to degrade, meaning they’ll just stay in the river and hurt aquatic wildlife, concentrating as prey animals are predated upon and threatening the future of thousands of species- and our own.

Once in the river, these microplastics can then find themselves in the gills and tissues of fish and other species. This can occur in many ways, such as fish or zooplankton ingesting the plastics, thinking they’re food, or mussels ingesting microplastics as well as other pollutants as filter feeders. Because the plastics don’t readily degrade, a process called biomagnification can occur. In biomagnification, microplastics and other toxins are ingested and travel up the food chain, affecting those who consume these fish.

So, what can you as an individual do to help? To start, avoid single-use plastics such as straws, plastic bags, or food containers. Although it might not feel like much, using reusable water bottles or bags makes a big difference. Be conscious of what you are pouring down drains and look for environmentally friendly or natural cleaners to prevent harmful chemicals from entering the river. The Tennessee River is home to hundreds of species and is incredibly unique with its biodiversity and uses for recreation and transportation, so we need to work to protect it! While it may seem that one person’s contributions cannot turn the tide, by implementing sustainable habits, advocating for environmentally conscious policies, and working together, the health of our river may be preserved.

This infographic is Lea Masson’s Girl Scout Gold Award project. She is a current junior in high school and is always looking for ways to utilize her artistic skills to make a change in the world. Special thanks to Maizie, Helaina, and Mr. Holt for all of their help and support! 

Be sure to follow on Instagram at underthesurface.project!