For 12-year-old Anna Du a love of the ocean and marine animals inspired her to build a device that hunts for microplastics.

These tiny plastic particles are barely visible to the naked eye, but they pollute aquatic ecosystems around the world, posing a serious threat to marine life.

"One day when I was at Boston Harbor, I noticed there was a lot of plastics on the sand, I tried picking some up, but there seemed to be so many more, and it just seemed impossible to clean it all up," the sixth grader from Andover, Massachusetts, told Boston 25 News.

So Du created an underwater ROV, or remotely operated vehicle, that uses infrared to detect microplastics in the ocean.

Courtesy of Anna Du

"I hope to be able to spatially map where microplastics are accumulating," she told Fast Company.

Du chose infrared not only because it keeps costs low, the technique also helps scientists distinguish microplastics from other, nonhazardous materials underwater without having to send samples to a lab.

The sixth grader is now gaining national attention for her invention, called the "Smart Infrared Based ROV to Identify and Remove Microplastics from Marine Environments." She was recently named a finalist in the 2018 Discovery Education 3M Young Scientist Challenge.

Du notes in her submission video for the annual challenge that 8 million metric tons of plastics are being dumped into the ocean every year. This plastic "constantly sinks to the ocean floor, making it virtually impossible to clean up," she says.

This marine debris never fully biodegrades. Instead, waves and sunlight break it up into smaller and smaller pieces.

"Some fish may eat the microplastics and those fish will be consumed up the food chain, throughout the global ecosystem and ultimately ending up on our plates, potentially causing a big health problem as toxins accumulate in our bodies," she continues.



Now that she's a finalist in the challenge, she'll get to work with 3M's scientists and engineers to help incubate her idea. Eventually she wants to create a machine that can also collect the plastic it finds, aiming to make "the most efficient machine cleaning up plastics," she told Fast Company.

When the young genius grows up, she wants to pursue a career that will help make a positive difference.

"I hope to be ... an engineer because I love the ocean and marine animals, and I want to do something to help," she says on her bio page. "In the future, with my engineering, I hope to be able to save people with all of my inventions."