More and more Americans recognize that plastic is a problem, but Imari Walker Karega, a PhD student at Sullivan Foundation partner school Duke University, has a knack for explaining it in accessible terms—and for dispelling myths and misconceptions about environmental issues.

And Walker gets the message out using one of the world’s most popular social media platforms—YouTube—through short, engaging videos that focus on the science of water quality and microplastics while also offering tips for getting into college and thriving while you’re there.

Walker earned her undergraduate degree in marine science from the University of California-Berkeley and is presently a researcher in the lab of Duke University environmental engineer Lee Ferguson. She studies the fate of plastic components as they break down and disperse in the environment.

One of Walker’s major worries: plastic water bottles. Many consumers believe bottled water is safer to drink than tap water—and they’re wrong. “The biggest concern is that you don’t know where that bottle of water has been before it ends up in your hand,” she said. “It could have been sitting in a warehouse or the back of a truck, in the heat—which speeds the plastic’s disintegration—for a long time. I worry about the chemicals and the microplastics that could be in there when you consume the water. And then we’re also polluting the environment with the empty bottle. It’s a double whammy.”

Part of Walker’s dissertation work is conducted at the CEINT Mesocosm Facility in Duke Forest, where she doses a simulated wetland ecosystem with microplastics to discover where they will eventually settle out. The water is full of the UV inhibitors that are added to plastic during the manufacturing process, Walker said, and the fish see tiny bits of plastic as tasty prey—and gobble them down.

According to Walker, the environment inside an animal’s stomach can cause some harmful chemicals to be released at higher concentrations than they would in seawater. She has used non-target mass spectrometry, a form of chemical forensic science, to find that high concentrations of surfactants, lubricants and biocides leach from plastic items commonly found on beaches, including balloons, trash bags, Styrofoam cups, and fishing line.

It’s well-known that some of these plastic additives can affect your health—like BPA, which can bind to estrogen receptors and influence bodily processes. The effects of hundreds of other plastic additives are still unknown.

But Walker said it’s difficult to make recommendations for alternativeslike reverse osmotic filtration systems in place of plastic bottles—when they are often expensive. “‘Environmentally friendly’ is not cost-effective,” she said. “It’s elitist, in a way, and it’s hard to encourage people to do good things when they’re not accessible.

On her Youtube channel, Walker delves into the topics she studies, including water quality and chemical exposure from consumer products. But the videos are not geared toward other scientists—instead, they’re produced for a broad range of ages and knowledge levels. “I feel like we researchers have been living in a little bit of a bubble when we go into our labs and interact mostly with other researchers,” she said. “The public needs to understand what environmental engineering is, what a researcher does, what our findings are and what the implications are for daily life.”

Her videos also focus on higher education, paying special attention to people in their teens who might be thinking about college. In recent years she served as a mentor for SENSOR Saturday Academy, which helps underrepresented Durham, N.C. middle-school students explore STEM through real-life water quality projects.

“For me personally, it’s important to communicate this work in a public-facing way because I didn’t see many black female environmental engineers—I’ve only met two or three, ever,” said WalkerI wanted to be that change and inspire others to think about this field.”

You can learn more about Walker at her website.

This article was adapted from a press release appearing on the Duke University website.

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