2 Simple Steps Can Remove 90% of Plastic From Tap Water

Researchers suggest boiling and filtering
By Arden Dier,  Newser Staff
Posted Feb 29, 2024 11:25 AM CST
2 Simple Steps Can Remove 90% of Plastic From Tap Water
This photo shows limescale or calcium carbonate at the bottom of a kettle. Researchers say calcium carbonate entraps microplastics during boiling.   (Getty Images/andriano_cz)

We can't seem to avoid microplastics in drinking water, at least without pricey filtration systems, but we can eliminate the vast majority with two simple steps, according to a new study. Microplastics and even smaller nanoplastics have been found in tap water around the world. The effects aren't fully known, but the plastic particles are thought to leach chemicals inside the human body. Exploring whether these particles could be easily removed, scientists created simulated samples of hard tap water containing nano- and microplastics (NMPs) at an average concentration of 1 milligram per liter, per the Washington Post and New Scientist. After boiling the samples for five minutes, then pouring them through a coffee filter, the levels dropped by nearly 90%, per the Post.

Boiling hard water, which contains dissolved calcium and magnesium, causes limescale or calcium carbonate (CaCO3). Though a pain to clean, it's beneficial in this case. During boiling, CaCO3 solidifies, forming crystalline structures that encase the tiny particles of polystyrene, polyethylene, and polypropylene, per the Post. These incrustants would build up over time to the point that they can be scrubbed away. But incrustants remaining in the water can be removed with a basic filter, like a coffee filter, says Eddy Zeng, an expert in microplastics at China's Jinan University and co-author of the study published Wednesday in Environmental Science & Technology Letters.

"We estimated that intakes of NMPs through boiled water consumption were two to five times less than those through tap water on a daily basis," Zeng adds, per New Scientist. Boiling and filtering removed 90% of NMPs from water samples containing around 300 milligrams of CaCO3 per liter, and 84% of NMPs from samples containing around 180 milligrams per liter, per the Korea Herald. But the strategy is less effective with soft water. In a sample with less than 60 milligrams of CaCO3 per liter, only around 25% of NMPs were removed, per New Scientist. Still, "our results have ratified a highly feasible strategy to reduce human NMP exposure and established the foundation for further investigations with a much larger number of samples," researchers say. (More microplastics stories.)

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