During 34 grueling days last summer, endurance athlete and scientist Dr. Andreas Fath set a world record by swimming all 652 miles of the Tennessee River, from its headwaters in Knoxville, to its mouth in Paducah, Ky.
Billed as a “swim for science,” the TenneSwim project also presented an opportunity for Fath — a professor of medical and life sciences at Germany’s Furtwangen University — to perform the first comprehensive analysis of the river’s water quality.
On Oct. 10, Dr. Fath visited the Tennessee Aquarium Conservation Institute to discuss his findings based on daily water quality tests and samples collected during his swim. To provide context to the results, he compared the Tennessee River’s levels to those he found in Germany’s Rhine River, which he swam and analyzed in 2014.
The levels of some chemical substances, such as pharmaceuticals, were lower in the Tennessee than in the Rhine. For example, Dr. Fath says, he and his team were unable to detect traces of diclofenac, a common painkiller which showed up in the upper reaches of the Rhine.
With respect to the level of microplastic pollution, however, the TenneSwim findings should trigger alarms about the American river’s health.
Samples Fath collected in the Tennessee River revealed microplastic concentrations 8,000 percent higher than those found in the Rhine. The levels of microplastic on the surface of the Tennessee were also 80 percent higher than in China’s Yangtze River, which a recent study found to be the source of 55 percent of all river-born microplastic entering the ocean.
“I did not expect such high levels of microplastics. Therefore, we triple-checked the results,” Dr. Fath says. “By looking for a reason, we rather quickly made a plausible guess.”
Despite the similar length of the Rhine and the Tennessee, he says, the dramatic difference between the levels of microplastic is likely a byproduct of differing approaches to waste management and recycling.
The TenneSwim analysis suggests the primary source of microplastic pollution in the Tennessee is not from microbeads, minuscule plastic spheres found in many cosmetic products and a primary source of microplastic pollution worldwide. Instead, Fath says, he is convinced the high levels are a byproduct of decomposition from large plastic waste in landfills.
“In Germany, plastic waste is collected separately, and then it’s combusted, recycled or exported to other countries like China, Vietnam, Thailand or Malaysia,” he says. “In the states bordering the Tennessee River, plastic waste is going to landfills. More than one-hundred million straws each day are going to landfills.
“Once the land is filled with plastic waste, it breaks up, step by step, with the help of microorganisms, ultraviolet light and mechanical forces. At the end of the day, the plastic is flushed into rivers as secondary microplastic.”
According to the National Oceanic and Atmospheric Administration, NOAA, inland sources are responsible for 70 percent of the trash found in the oceans. Most of that, including plastics, is washed off streets, down storm drains, and flows directly into our waterways.
"By some measures the Tennessee River appears to have fairly good water quality. The high levels of microplastic particles are the real shocker,” said Dr. Martin Knoll, professor of Geology and Hydrology at Sewanee: The University of the South. “A major contributing factor must be the abundant plastic waste we all see on roadsides. This plastic can easily make its way underground through the porous limestone and quickly move into the river."
If the rate of microplastic entering the ocean is left unchecked, scientists predict there could be more plastic particulate than fish in the ocean by 2050. Although much of the attention placed on microplastic is directed at its presence in marine environments, river-borne microplastic is a major contributor to microplastic in the ocean. Modeling of the source of this pollution has found that waterways like the Tennessee deposit an estimated 1.15 to 2.41 million metric tons of plastic waste into the ocean every year.
In light of the growing awareness of — and alarm about — microplastics, Fath’s project attracted support from many agencies along his route, including the Tennessee Aquarium, Sewanee: The University of the South, The Nature Conservancy, the Lyndhurst and Riverview Foundations, River Discovery Center of Paducah, the University of Georgia River Basin Center, Ijams Nature Center, Tennessee State Parks and Tennessee Valley Authority.
When Dr. Fath emerged from the Tennessee River after 34 days of swimming, he was free from infections, despite swimming with some open wounds. Comparatively, during his 2014 traversal of the Rhine, Dr. Fath became sick with nausea and diarrhea from an infection he contracted in the final week of his swim.
Given the detected levels of microplastics and the presence of some industrial chemicals that have been outlawed in Europe since 2006, however, the Tennessee River is far from hospitable to the abundance of aquatic life that live in the waterway and its many tributaries.
“Based on the findings, it is not a healthy river at all,” Dr. Fath says.
That failing grade is especially problematic, ecologically, since the Tennessee River is a primary artery in an aquatic network that some biologists have described as an “underwater rainforest.”
More than 1,400 aquatic species reside in waterways within a 500-mile radius of Chattanooga, including about three-quarters (73.1 percent) of all native fish species in the United States. More than 90 percent of all American mussels and crayfish species live within that same area, as do 80 percent of North America’s salamander species and half of its turtle species.
“The microplastic concentration, together with the chemical cocktail found in the river, is not a good combination for aquatic life in the Tennessee River,” Dr. Fath says, adding that the ecological damage could still be mitigated if proper steps are taken.
The safeguards Dr. Fath suggests to reduce the presence of chemical pollutants include the implementation of a treatment step in sewage plants to reduce the release of trace substances and legislation to reduce and control release limits for industries, agriculture and hospitals. To curb the pandemic of microplastic pollution, however, he suggests encouraging wider scale adoption of recycling programs and a nationwide reduction in the use of single-use plastic items like shopping bags and straws.
“Plastic is a smart and important material in industries with a lot of economic benefits,” Dr. Fath says. “We appreciate its durability, but it is madness to use this non-degradable material for packaging of articles which are only used for minutes or hours. If we do not change that, we are going to wrap up the world with plastic.”
The announcement of the TenneSwim analysis and its foreboding finding regarding microplastic comes as the Tennessee Aquarium enters its second year of involvement in the Aquarium Conservation Partnership (ACP), which formed in 2017. This consortium of 22 aquariums was formed to speak out against and lead the charge in combating microplastic pollution by eliminating single-use plastic in their operations and encouraging similar lifestyle changes in their visitors.
Membership in the ACP builds upon the more than two decades the Aquarium has served as a leader in freshwater conservation and environmental advocacy. The Tennessee Aquarium Conservation Institute, the Aquarium’s research and conservation arm, seeks to preserve freshwater life through scientific study, strategic organizational partnerships and educational outreach.
“We hope that, through our own efforts to stem the tide of microplastics, all of our guests will look for ways they can join us in reducing the amount of plastics in our aquatic environments,” said Dr. Anna George, the Tennessee Aquarium’s vice president of Conservation Science and Education. “The solution to plastic pollution is in our hands.”
Learn more about ways you can reduce single-use plastics at: https://www.tnaqua.org/our-hands