The study is one of the first of its kind in this state

Microplastics – tiny pieces of plastic less than five millimeters in size – can cause big problems when they find their way into the ecosystem.

Most research being done now has focused on these tiny pollutants in oceans and estuaries, however, researchers at Tennessee Tech University have turned their attention to the freshwater of Tennessee.

Environmental engineering graduate student Caroline Hitchcock, with assistance from Tania Datta, Ph.D., associate professor of civil and environmental engineering, and Justin Murdock, Ph.D., professor of biology, have started investigating microplastics, specifically their presence in wastewater treatment plants across Tennessee. As the state boasts more native fish species than any other in the U.S., and the second-highest species diversity of freshwater mussels, knowing how pollutants might be entering the waterway is vital knowledge. The study is one of the first of its kind in this state.

“Even to this day, when you look up Tennessee wastewater microplastics, there are only two or three things that pop up, and one of those is one of my conference posters,” Hitchcock said.

Landfills and litter were long thought to be major sources of microplastics in water, however recent studies from other states have found that wastewater treatment plants can actually add more plastic to the water coming through its facilities.

There are various reasons for this. For example, vehicle tires will shred tiny pieces of plastic onto roads as they drive, and rainwater sweeps this into leaky wastewater pipes. Microscopic pieces of plastic can even come from clothing being washed in a washing machine. The water drains into the sewer system, taking the microplastics with it. Many wastewater plants may not have the right processes to remove these microplastics.

“Nobody has done a study on if and how much wastewater treatment plants are contributing microplastics to Tennessee’s aquatic ecosystem,” Datta said.

Hitchcock, Datta and Murdock’s research has two main objectives: develop standardized methods to sample, analyze and detect microplastics in wastewater, and apply those methods to investigate microplastics in wastewater treatment plants in Tennessee.

Hitchcock started her research as an undergraduate student. Because not many other studies had been accomplished in wastewater, she began investigating the literature for various techniques to sample for microplastics and attempted to recreate them.

“When you look at the microplastics research in wastewater, they often won’t detail the methodology so that it’s replicable,” Hitchcock said. “So, it’s very complicated. It’s been sort of a trial-and-error process since the beginning.”

Now as a graduate student, she has spent her time discovering the best techniques for detecting microplastics in wastewater samples. She will continue to collect and analyze samples through the end of this year to investigate if different seasons, treatment processes, or status of sewage infrastructures make a difference in her results.

The facilities at the Water Center at Tennessee Tech have been especially helpful, Hitchcock said, for procuring a FT-IR microscope and allowing her to use it for experimentation and analysis.

Hitchcock’s research is set to not only provide valuable insights on microplastics in Tennessee’s waters, but to also give her experience and knowledge that she will take with her once she graduates and heads off to her own career.

“I really found a passion in water,” she said.

Photo courtesy of Tech.

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