Drinking Boiled Tap Water Reduces Human Intake of Nanoplastics and Microplastics

Tap water nano/microplastics (NMPs) escaping from centralized water treatment systems are of increasing global concern, because they pose potential health risk to humans via water consumption. Drinking boiled water, an ancient tradition in some Asian countries, is supposedly beneficial for human health, as boiling can remove some chemicals and most biological substances. However, it remains unclear whether boiling is effective in removing NMPs in tap water. Herein we present evidence that polystyrene, polyethylene, and polypropylene NMPs can coprecipitate with calcium carbonate (CaCO3) incrustants in tap water upon boiling. Boiling hard water (>120 mg L–1 of CaCO3) can remove at least 80% of polystyrene, polyethylene, and polypropylene NMPs size between 0.1 and 150 μm. Elevated temperatures promote CaCO3 nucleation on NMPs, resulting in the encapsulation and aggregation of NMPs within CaCO3 incrustants. This simple boiling-water strategy can "decontaminate" NMPs from household tap water and has the potential for harmlessly alleviating human intake of NMPs through water consumption.