Nathan Gael Montelongo
7th Grade, Lorenzo De Zavala Middle School
La Joya, TX
Shellfish Contributions to Ecosystem and Human Health: Evaluating Chitosan’s Natural Ability To Remove Microplastics
Gael was upset to learn his fishing catch could contain microplastics. He used shellfish-derived chitosan to clean pollutants from water. He showed chitosan cleaned 55-75 percent of plastic particles, and zebrafish embryos had better survival in chitosan-treated water. He also built a raft which senses water quality and releases chitosan.â€
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Project Background
On a fishing trip to the Rio Grande, Gael and his older brother were getting ready to clean their catch. “A local fisherman told us to make sure we cleaned the fish thoroughly because recent catches had been found to be excessively contaminated with microplastics and weren’t consumable,” he recalls. Gael became determined to find a way to clean microplastics out of water. He landed on shellfish. “They can filter water, because their shells contain chitin, which can be converted into chitosan, a biodegradable material known to bind pollutants.”
Tactics and Results
Gael collected water samples with visible plastic from the Rio Grande. Then, he took shellfish shells from local restaurants, dried them, and ground them up to make chitosan powder. Chitosan sticks to pollutants and pulls them out of the water. Gael first tested his chitosan on glitter, and found it picked up between 55 and 75 percent of the glitter. He then tested it on his river water samples. “as the chitosan coagulated the water color began to clear,” he says. A test with Arduino sensors also showed the water quality was improving. He also tested his chitosan on zebrafish (Danio rerio) embryos, watching their development for four days. The embryos in chitosan-treated water survived more often and had better development than those in regular river water. Finally, Gael designed a raft that could measure water quality, and release chitosan to clean the water in response.
Beyond the Project
Gael is part of a year-round baseball team, including playing in a youth baseball world series. “It is an amazing experience I get to share with my younger brother, because we play on the same team,” he says. He also runs track. Gael would like to become a mechanical engineer. “My grandma was bedridden due to cancer when I was smaller and I watched my grandpa struggle,” he says. “My brother and I built him a small ramp to be able to help her into the shower. Later I learned that these are the types of things engineers do.”
