From waste to wonder: This 13-year-old used peanut shells to help remove pesticides from fruits and vegetables

A discarded peanut shell could soon become an unexpected tool for making your fruits and vegetables cleaner, thanks to a 13-year-old Indian-American student from Minnesota.

Arika Kundu, a seventh-grade student at Minnetonka Middle School East in Shorewood, has developed a method that uses peanut shells to reduce pesticide residues on fresh produce. Her innovation, called LIGNEX: A Novel Biosorption-Based Approach, has earned her a place among the 10 finalists in the 2026 3M Young Scientist Challenge.

The national competition recognises middle school students aged 11 to 14 who create science-based solutions to real-world problems. As a finalist, Arika will now spend the summer working with a 3M scientist before competing in the final round in October.

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The winner will receive a $25,000 grand prize and the title of "America's Top Young Scientist."

Turning farm waste into a cleaning solution

Pesticide residues can remain on the surface of fruits and vegetables even after they are harvested. While washing produce helps remove dirt and some chemicals, it does not always get rid of everything.

Instead of relying on expensive materials, Arika looked at something that usually ends up in the bin: peanut shells.

She developed a method that transforms discarded peanut shells into a material capable of removing pesticide residues from fresh produce. Her project uses a scientific process known as biosorption, allowing agricultural waste to serve a second purpose instead of being thrown away.

Think of it as a natural sponge. Certain materials can attract and hold chemicals, and in Arika's project, the treated peanut-shell material acts like a natural filter. When fruits and vegetables come into contact with it, the material captures pesticide residues from their surface, potentially reducing the amount of pesticides left behind.

A shot at America's top young scientist title

The 3M Young Scientist Challenge, organised by 3M and Discovery Education, is now in its 19th year. The competition invites students in grades five to eight to develop scientific solutions for everyday challenges.

This year, 10 finalists from across the United States were selected after submitting one- to two-minute videos explaining their innovations. Judges evaluated the entries based on creativity, scientific knowledge and communication skills.

Throughout the summer, each finalist will work closely with a 3M scientist to refine their project before presenting it during the finals on October 12 and 13 at the 3M Innovation Center in St. Paul, Minnesota. The students will also take part in live challenges and answer questions from the judging panel.

"I wanted everyone to benefit"

Arika says her goal extends beyond winning the competition.

"I entered the 3M Young Scientists Challenge to improve my innovation and turn it into a product that everyone can benefit from," she said, as quoted by Young Scientist Lab.

She also shared that she received the Minnesota State Merit Award last year and hopes being named a national finalist will give her the opportunity to receive expert guidance from 3M scientists.

Looking even further ahead, Arika already has her sights set on a career in space science.

"In 15 years, I hope to be an astrobiologist, specifically in computational biology," she said.

Scientific curiosity has no age limit

Brian Shaw, Chief Executive Officer of Discovery Education, praised this year's finalists for turning simple ideas into meaningful innovations.

"The finalists of this year's 3M Young Scientist Challenge prove you can be a scientist at any age," Shaw said. "Each remarkable student pursued their curiosity with persistence, turning an idea into an innovation. We cannot wait to see where their ideas take them," Shaw said according to an official statement.

Over the years, finalists in the competition have developed projects addressing food safety, water conservation, air pollution, energy use and cybersecurity. Several have gone on to file patents, deliver TED Talks and launch nonprofit organisations.