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An Unlikely Ally in the Fight Against Plastic Pollution

Northwestern researcher takes inspiration from baleen whales

Mike M. McMahon | April 20, 2020
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Human beings can be incredibly determined when it comes to finding efficient solutions to solve complex problems, but we often miss what’s right in front of us: 3.5 billion years of natural selection that has shaped nearly every facet of our environment with an eye towards maximum efficiency. Believe it or not, some of our most innovative technologies—from highspeed bullet trains and Velcro to solar panels and wind turbines—have been inspired by plants and animals in nature.

In order to address the issue of microplastic pollution, Kyoo-Chul (Kenneth) Park, assistant professor of mechanical engineering at Northwestern University’s McCormick School of Engineering, is taking inspiration from some of the world’s largest living animals—whales.

Because plastic was designed for uses that require resistance to degradation, most types of the material never fully break down when they enter the environment. Microplastics—fragments of plastic measuring five millimeters or smaller—are especially prevalent in waterways and oceans and have been found in everything from tap water to seafood. For the first time ever, researchers recently revealed that they had discovered microplastics in the human digestive tract.

“When it comes to the solving the problem of microplastic particles in the environment, I tried to think of relevant biological species. Baleen whales came to mind immediately,” says Park, who specializes in bio-inspired engineering solutions.

Baleen whales get their name from their “teeth,” which are actually comprised of long plates and comb-like filaments known as baleen that hang from the animals’ upper jaw. When feeding, these whales strain great quantities of ocean water through their baleen to capture food such as plankton, krill, crustaceans, and small fish. There are a variety of species of baleen whale including the blue, bowhead, humpback, and gray whale.

Baleen plates
Baleen plates and hairs allow whales to strain large volumes of ocean water to capture food. They are made of a protein similar to human fingernails.

“My goal is to analyze the whales’ particle capture process and optimize the structure of baleen hairs to capture unwanted microplastic from water,” explains Park, whose research focuses on the ways in which particles flow around textured surfaces—what’s known as interfacial transport phenomena. “My research team at Northwestern has already configured a simplified model system to test microplastic particles and fibers based on baleen. With this model, we’re starting to develop important principles associated with the physics as well as chemistry to solve this problem.”

The world currently produces more plastic waste than ever, adding about 300 million additional tons per year—nearly equivalent to the weight of the entire human population. Most of that plastic—approximately 79 percent—ends up in landfills or the environment. Despite the growing accumulation of plastic waste, the public health impacts of recurrent consumption and exposure remain unclear.

Park draws an analogy with carbon nanotubes, whose deleterious health effects were not recognized until relatively recently. “About 15 years ago, people did not worry about carbon nanotubes. Some researchers did not wear masks when handling them, and there was very little in terms of strict regulation. Gradually, people discovered that carbon nanotubes were being absorbed or collected in our lungs when inhaled. It’s too soon to say at this point, but I’m worried that something similar could happen with microplastic particles.”

Park is a researcher in the Program on Plastics, Ecosystems, and Public Health, a multi-institutional initiative at the university-wide Paula M. Trienens Institute for Sustainability and Energy. The Program brings together collaborators from academic, civic, NGO, and industrial partner institutions to solve challenges related to the global use and accumulation of plastics.

Park views his work as an essential piece of a broader, multidisciplinary approach to developing scalable solutions.

“Many people talk about the importance of designing new types of materials that biodegrade. But just as important is developing technologies to collect the many microplastic particles that are already out in the environment. I hope my work can contribute to the big picture vision of the Program at the Trienens Institute.”

Image credit: Todd Cravens