Virginia teenager Mia Heller’s filtration system harnesses the power of ferrofluid, a magnetic oil that binds to microplastics in flowing water

Microplastics pose a growing global concern as they infiltrate not just the environment but also humans and animals. Joker/Alexander Stein/ullstein bild via Getty Images

A few years ago, teenager Mia Heller came across an article in her local newspaper about ongoing water quality issues in her neighborhood in Warrington, Virginia. Tests had revealed that the water available for daily consumption was highly contaminated with PFAS and microplastic pollution. The article further reported that government agencies would not be providing any funds for filtering the water.

“It was up to people to provide their own filtration,” says Heller.

Not long after the article came out, Heller’s parents invested in an advanced water filtration system at her home. The system, however, required constant upkeep. Seeing her mother replace the water filter membranes time and again, Heller set out to find a better solution.

“It inspired me to design a filter without the use of membranes, to decrease the costs and maintenance needs associated with water filtration,” says the now 18-year-old student at Kettle Run High School. Through her school, she also attends a half-day program for math, science and technology at nearby Mountain Vista Governor’s School.

In the 2025 Regeneron International Science and Engineering Fair, Mia Heller received a $500 award from the Patent and Trademark Office Society (PTOS) for her innovative, low-cost and efficient water filtration technology. Regeneron International Science and Engineering Fair

The pervasiveness of microplastics

The Environmental Protection Agency defines microplastics as small particles measuring about 1 nanometer to 5 millimeters in size. These tiny particles pose a growing global concern as they infiltrate not just the environment but also humans and animals.

“Micro- and nanoplastics are getting into our bodies,” says Matthew J. Campen, a toxicologist at the University of New Mexico in Albuquerque. A recent study revealed that microplastics have been found in 1,300 species, including humans. So far, these pollutants have been detected throughout the human body, from the brain to the insides of bones; concentrations have also been found in testes, semen and the placenta of unborn fetuses.

Microplastic intake by organisms has increased sixfold since 1990, and plastic production continues to grow. A 2025 University of New Mexico study Campen co-authored revealed that concentrations of microplastics found in human brain tissue have increased by a sharp 50 percent in less than a decade.

“There are still a lot of questions as to whether these plastics are really impacting our health at this point,” says Campen, who also studies the effects of complex inhaled pollutant mixtures on respiratory, cardiac and vascular outcomes. He goes on to note the existence of evidence that “there might be issues for cardiovascular disease and potentially neurological disease.” The links, however, are not strong enough to be conclusive.

Though the exact impacts of microplastic consumption on human health are unclear, a number of recent studies have linked it to adverse health issues like cancers, respiratory and cardiac diseases, hormonal disruptions, Alzheimer’s disease and other noncommunicable diseases.

Quick fact: What's the difference between primary and secondary microplastics?

• According to the EPA, primary microplastics are tiny plastics manufactured for things like cosmetics and biomedical products. Secondary microplastics are plastic pieces that have broken down from larger plastic consumer products.

A new take on water filtration

While several water filtration systems are available, they aren’t all efficient and easily accessible to everyone. Traditional systems often rely primarily on chemical treatments and may also require labor-intensive upkeep and frequent membrane changes. They also come with high price tags and maintenance costs.

In the spring of 2024, Heller had the idea for her filtration system, but she really got working on it in the summer of 2025. By early January of that year, after tinkering in her garage and kitchen, she had a working prototype.

“It was essentially just a container,” she says. Within the container was her filtration system, what she called a “spinning magnified vial.” Heller harnessed a reusable magnetic oil called ferrofluid to selectively bind to microplastic particles as water flows through her filtration system. While her model successfully filtered out the microplastics from the water in two simple steps, the system still required constant maintenance, as it did not self-recycle the ferrofluid.

“But if I could create a system that was able to basically clean itself and reuse material," she explains, “the maintenance needs could go down by a lot.”

Determined to find an answer, Heller continued experimenting. One of the main obstacles she faced was figuring out how to place her units so that the ferrofluid—a liquid thicker than water—would be able to move into the water chamber above it without getting clogged. Along with the ferrofluid flow, the process of magnetic separation followed by the recovery of ferrofluid also needed to work together as one system rather than competing with each other.