June 21, 2024

Microplastic Pollution in Local Waterways: An Explainer

Research from German wastewater chemist Andreas Path has shown that the Tennessee River is one of the most plastic-polluted rivers in the world, nearly doubling the plastic content of China’s Yangtze River and carrying more than 80 times as much pollution as the Rhine in Germany. According to Path, the biggest source of plastic pollution is most likely large landfills, which hemorrhage tiny plastic particles–dubbed microplastics when below 5 millimeters in length–each time it rains.

The Tennessee River flows through the heart of downtown Knoxville, and is fed by rural and urban tributaries throughout the surrounding area. Unfortunately, these streams and creeks are also suffering from high levels of plastic-pollution, although the source may be very different.

Gillian Polino is a graduate student at the University of Tennessee, where she studies microplastics in the local urban waterways. As she explains, the microplastics in these waterways are predominantly “fibrils” or small threads of plastic. Polino thinks these fibrils may be coming from our wastewater after we wash clothes made with plastics like polyester.

Although Polino’s data is still preliminary, research from across the world has connected polyester clothing with microplastic pollution.

How microplastics affect our health

Although researchers from the UK, Australia, and here in Tennessee have discovered that microplastics can be deadly to wildlife–especially to marine animals–data on how these pollutants affect humans is still frustratingly limited. Thus far, the scientific community has focused primarily on finding out how much we’re exposed to microplastics on a daily basis as well as how they affect the health of other organisms.

Nevertheless, scientists across a range of fields are concerned about the amount of microplastics that we are exposed to on a daily basis. A 2021 review in premier science journal Nature outlined the effects of prolonged or intense microplastic exposure that have scientists most worried.

One of the central and most well-studied dangers of microplastics is their ability to amplify the danger of other toxic chemicals. As Polino explains, “because of their chemical composition, environmental toxins are often able to attach to micro plastics, then remain inside an organism for much longer than they ordinarily would.” This increased exposure increases the risk of bacterial infection as well as the damaging effects of toxins like heavy metals and pesticides.

Scientists are also concerned about microplastics accumulating in areas like the gut and the liver, potentially forming dangerous blockages. This is especially dangerous for small animals like snails and mice, although scientists like ecotoxicologist Tamara Galloway at Exeter University in the UK believe that the steady accumulation of plastics in our environment will soon make them hazardous to larger animals as well.

How is the problem being addressed around the country?

According to the independent data outlet World Population Review, the US uses the most plastic in the world by far. Data from the EPA shows the US producing more than 35 million tons of plastic each year, with the vast majority exported overseas or headed to the landfill, where it is eventually washed into waterways and ecosystems across the country. Unfortunately, the US also lags behind much of the world in regulating plastic usage; it is one of two countries among 189 which declined to ratify the addition of plastics to the Basel Convention, an international agreement regulating the movement of hazardous materials. The US has also failed to join the nearly 100 countries that have passed restrictions on single-use plastics.

The federal government has largely left states to implement their own measures to contain the plastic they produce and throw away, and California is one notable exception to the national trend. While there is still work to be done, the state has imposed a ban on single-use plastic bags as well as the use of microplastics in wash-off products like deodorants–a more strict requirement than the national 2015 Microbead-free Waters Act, which pertains only to facial scrubs and exfoliants. The state has also passed a bill for the long-term reduction of single-use plastics in the next ten years.

Critically, California lawmakers are also investigating methods to prevent the spread of microplastics through runoff and wastewater by investigating and improving storage and filtration practices.

How can the problem be addressed locally?

In the absence of strong state and federal regulation of plastic production and disposal, the task is up to city government, local businesses, and citizens.

In the wake of a 2019 bill signed by Governor Bill Lee, local governments like the Knoxville city government are not allowed to regulate or ban the use of plastics like utensils or bags. With this restraint in place, the city’s leadership has been forced towards less effective measures like expanding the range of materials that can be processed for recycling. The city is free to implement policies to improve the filtration of microplastics from local wastewater treatment facilities and to better-contain plastics in landfills during rain events, but has not yet done so.

While most local branches of national chains do little to reduce their plastic output, some local businesses are stepping in to fill the gap. For example, KnoxFill is a local “refillery” where customers can buy and refill products like shampoo or laundry detergent–which are typically purchased in single-use-plastic containers. Knoxville is also home to a number of farmers markets, as well as restaurants and bakeries that use local produce, all of which reduce the city’s reliance on plastic packaging.

All told, the burden of reducing plastic buildup in Knoxville’s ecosystems, animals, and children rests largely on the local citizens. As Polino says, “in the absence of a system that supports sustainability, it’s up to us to do what we can to reduce the amount of plastic we use.”

Listen in as Gillian Polino talks about the dangers and prevalence of microplastics in Local waterways