A new scientific study has found that extracts from moringa tree seeds can remove up to 98.5% of microplastics from drinking water — a discovery that could have significant implications for communities worldwide, including those in the Caribbean. According to Antigua News Room, the findings were published in April by a team of researchers from Brazil and the United Kingdom.
The moringa tree, long celebrated as a "miracle tree" for its nutritional and medicinal properties, has been used as a water purification agent for thousands of years. Ancient Greeks, Romans and Egyptians all employed the tree for this purpose, according to Adriano Gonçalves dos Reis, a study author and professor at the Institute of Science and Technology of São Paulo State University. He and his colleagues have spent a decade studying the seeds' properties as a natural coagulant — a substance that causes tiny particles in water to clump together so they can be filtered out.
Microplastics are tiny plastic fragments that can be as small as one micrometer, or 1/25,000th of an inch. They have been detected virtually everywhere on earth, from deep ocean trenches to mountain peaks. A 2024 study found microplastics in 83% of tap water tested globally, and researchers have identified the particles in human brains, reproductive organs and cardiovascular systems. Animal studies have linked microplastic exposure to reproductive problems and hormone disruption, though scientists are still working to fully understand the health impacts on humans.
For this study, the researchers focused on PVC microplastics, which are among the most hazardous and most prevalent in drinking water. Testing particles with a mean size of 18.8 micrometers — roughly a quarter of the thickness of an average human hair — they found that moringa seed extracts achieved 98.5% effectiveness at removing the particles when used in filtration systems.
That level of efficiency is broadly comparable to aluminum sulfate, known as alum, a chemical coagulant in widespread use at water treatment facilities. The moringa seeds actually outperformed alum in more alkaline water conditions. Gonçalves dos Reis highlighted several advantages of the natural alternative: the seeds are renewable, biodegradable, produce less sludge and carry fewer toxicity concerns. Aluminum, by contrast, can be toxic at high levels and has been associated with neurodegenerative diseases.
Matthew Campen, a distinguished professor of pharmaceutical sciences at the University of New Mexico Health Sciences Center, who was not involved in the research, said using a natural product in place of aluminum-based filtration systems "may offer a cheaper and more sustainable solution to removal of PVC microplastics." He also noted it would eliminate the need for aluminum mining, which carries its own environmental costs.
However, the researchers acknowledge real limitations. A single moringa seed can treat approximately 10 liters of water. "While this is promising," Gonçalves dos Reis said, "it would require a very large quantity of seeds for large urban treatment plants handling high flows." The method may therefore be best suited for small communities or areas where access to chemical coagulants is limited. Researchers also noted that higher seed usage could introduce more organic residue into the water, requiring additional removal steps.
Campen said further research is needed to understand how the seed extracts degrade, what happens to the captured PVC, and how scalable and cost-effective the approach can be at larger scales. He also stressed the importance of testing whether moringa is effective against other types of microplastics and nanoplastics — the smallest particles, roughly 1,000th the average width of a human hair, which are considered most likely to penetrate the human body.
Gonçalves dos Reis expressed confidence that moringa seeds will prove effective against other plastic types, and said this is the focus of the team's future research.
Campen underscored the urgency of finding solutions. Human exposure to microplastics and nanoplastics is rising steadily, he said, and this trend "is unlikely to change for many decades to come."
