Boiling tap water is good for more than just killing certain harmful pathogens. It can also destroy contaminants such as microplastics and chemicals, making drinking water safer to drink.
A new research letter published in Environmental Science & Technology Letters indicates that boiling tap water for just five minutes could reduce the amount of microplastics by up to 90 percent. Researchers from Guangzhou Medical University and the Center for Environmental Microplastics Studies in China recommend boiling water in nonplastic electric kettles on gas stoves to remove impurities such as polystyrene, polyethylene, and polypropylene.
According to the researchers, boiling water has been used since ancient times as a purification method in some Asian countries. “This simple boiling-water strategy can ‘decontaminate’ [nano- and microplastics] from household tap water and has the potential for harmlessly alleviating human intake of [nano- and microplastics] through water consumption,” they wrote.
Harder Water Captures More Microplastics
Water of a certain alkalinity and hardness typically produces incrustants—insoluble mineral remnants like calcium carbonate—upon boiling. For the study, the researchers hypothesized that calcium carbonate encounters nanoplastics as it crystallizes in hot water. The calcium carbonate then encapsulates the nanoplastics as it becomes the flaky crust you sometimes see at the bottom of your tea kettle.
The study showed that boiling hard tap water containing 300 milligrams per liter (mg/L-1) of calcium carbonate reduced nano- and microplastics by nearly 90 percent, while water containing 80 mg/L-1 reduced particles by 84 percent. In soft water samples containing less than 60 mg/L-1 of calcium carbonate, boiling still reduced plastics by over 25 percent.
Hellbound and Down 