A fishing trip along the Rio Grande led a La Joya, Texas, seventh-grader to investigate whether discarded shellfish shells could help remove pollution from water. Nathan Gael Montelongo became interested in the problem after a local fisherman warned him that recent fish catches had been found to contain excessive microplastics. According to Nathan’s profile on the Society for Science, he eventually developed chitosan powder from shellfish shells collected from local restaurants and tested its ability to remove pollutants from water. His project went further, with experiments involving Rio Grande samples, zebrafish embryos and a prototype raft that could monitor water quality and release chitosan when needed. The project earned Nathan a place among the 30 finalists of the 2026 Thermo Fisher Scientific Junior Innovators Challenge.
A fishing trip sparked the idea
Nathan’s project began with an experience that connected a local environmental concern with a material that is often discarded. While fishing in the Rio Grande with his older brother, Nathan was preparing to clean their catch when a local fisherman warned them about microplastic contamination in recently caught fish. The warning prompted him to look for a way to remove plastic pollution from water.He turned his attention to shellfish. Their shells contain chitin, a natural material that can be processed into chitosan. Chitosan is biodegradable and can bind with pollutants, making it useful for investigating whether shellfish waste could be repurposed as part of a water-cleaning system.Rather than buying shells specifically for the experiment, Nathan collected discarded shellfish shells from local restaurants. This also gave the project a waste-reduction element by repurposing discarded shellfish shells.
Restaurant shells became chitosan powder
Nathan first dried and ground the restaurant shellfish shells. He then used the material to produce chitosan powder for his experiments. His initial test used glitter as a visible stand-in for small particles. When Nathan added the chitosan, it picked up between 55% and 75% of the glitter, according to the Society for Science. The result encouraged him to move on to actual water samples from the Rio Grande. He collected samples containing visible plastic and introduced the chitosan to see how the material would affect the polluted water.As the chitosan coagulated, Nathan observed the water becoming clearer. This provided a visible indication that particles were being pulled together by the material rather than remaining dispersed throughout the water.
Testing the material on Rio Grande water
Nathan did not stop with a visual comparison. He also used Arduino sensors to measure changes in water quality after treatment. The sensor-based testing indicated that water quality was improving after the chitosan treatment. This gave him another way to examine the performance of the material beyond simply looking at whether the water appeared clearer.The project was specifically focused on chitosan’s ability to remove microplastics and other pollutants. The results described by the Society for Science come from Nathan’s experimental work and do not establish that the process can remove all pollutants from natural waterways or make contaminated water safe to drink. Instead, the experiments showed how a material made from discarded shellfish shells could be investigated as a possible tool for removing contaminants from water.
Zebrafish provided another test
Nathan also examined whether treating polluted water with chitosan could affect biological conditions. He exposed zebrafish embryos (Danio rerio) to different water conditions and observed their development for four days. The embryos placed in chitosan-treated water survived more often and showed better development than those exposed to untreated Rio Grande water.This part of the project allowed Nathan to look beyond the physical appearance and sensor readings of the water. By observing living organisms, he could investigate whether the treated water produced different biological outcomes in his experimental setup. The zebrafish experiment was conducted on embryos under laboratory conditions, so the findings do not by themselves demonstrate that chitosan treatment would produce the same effects for aquatic organisms throughout the Rio Grande.
A raft that could respond to water quality
Nathan then took his idea from a material-based experiment towards a potential automated cleanup system. He designed a raft capable of measuring water quality and releasing chitosan in response to the measurements. The concept was to create a system that could detect changes in water conditions and administer the treatment rather than requiring someone to manually add the material.This makes the raft an extension of his original experiment. The project began with shellfish waste and the question of whether its chitosan could capture pollutants. It then developed into an automated concept combining water-quality monitoring, pollutant treatment and a floating platform. The design remains a student research prototype rather than a demonstrated large-scale solution for cleaning the Rio Grande.
From waste material to environmental research
Nathan’s project brings together several ideas: recycling shellfish waste, testing a biodegradable material, monitoring water quality and exploring an automated approach to pollution cleanup. His work has also earned him a place among the 30 finalists in the 2026 Thermo Fisher Scientific Junior Innovators Challenge. Society for Science and Thermo Fisher Scientific say the finalists will travel to Washington, DC, from October 23 to 28 for the competition’s Finals Week. Each finalist receives a $500 award, while the students will compete for more than $100,000 in prizes.For Nathan, the project started with a warning about contaminated fish during a fishing trip. It eventually became an experiment that turned restaurant shellfish waste into chitosan, tested the material on polluted river water and zebrafish embryos, and produced a prototype for an automated cleanup raft. The work illustrates how an everyday waste product can become the starting point for a broader environmental engineering project.
