EarthTalk: Removing Microplastics From Drinking Water

As concern over microplastics grows, so do efforts to avoid consuming them. Drinking water is a primary entry point for microplastic accumulation in our bodies. While we trust municipal waste water treatment plants to remove countless other contaminants, their ability to remove these plastics varies. A study by Ohio State University, led by Dr. John Lenhart and Megan Jamison, found that two-thirds of microplastics in raw and treated samples were smaller than one micrometer. Jamison noted, “We’re seeing a much higher concentration of plastics in terms of particle count because we’re seeing a lot of those nanoplastics that have been unreported in other studies.”

Given the uncertainties around current waste water treatment’s efficacy for microplastics, scientists are developing novel removal methods. One approach uses polymers originating from okra pods and fenugreek seeds, which stick to microplastics, clumping them together for easier removal. This also presents a safer, biodegradable alternative to the current use of synthetic wastewater treatment polymers.

Researchers at the University of Missouri have engineered a strain of algae that produces limonene, the oil best known for giving oranges their scent. It alters the algae’s surface, making it water repellent. When introduced to contaminated water, microplastics, which are also water repellent, adhere to the algae and can be removed. The creator of this algae, Susie Dai, aims to use this method to not only clean water, but also recycle the microplastics collected into safer, bioplastic materials. Elsewhere, Princeton Engineering has discovered a way to us egg protein to create an aerogel capable of removing microplastics with 99 percent efficiency. While scaling this aerogel is a challenge, Sehmus Ozden, a postdoctoral research associate, emphasizes the product’s potential. “Activated carbon is one of the cheapest materials used for water purification,” she says. “We compared our results with activated carbon, and it’s much better.”

While awaiting these innovations, there are ways to reduce microplastic consumption. Boiling water before filtering it creates limescale, which traps microplastics that at-home filters can easily remove. This works best with hard water, but even with soft tap water, boiling can remove about 25 percent of microplastics. Also, avoiding bottled water is an easy way to reduce your microplastic intake, as it is linked to higher microplastic concentrations than tap water. Finally, addressing the source of pollution is essential to the success of the global fight against microplastics. Microfibers from polyester clothing are a significant contributor to water contamination. Switching to natural fabric alternatives can reduce the microplastics entering our waterways in tandem with efforts to filter them from our drinking supply.