Researchers from the SFI Centre for Advanced Materials and Bioengineering Research (AMBER), Trinity, and University College Dublin are suggesting that tap water creates a shield-like barrier in plastic household products that prevents the release of microplastics.

According to the team, tap water features trace elements and minerals that prevent plastic — for instance from within a plastic pitcher — from degrading and the subsequent release of microplastics, which could potentially include trace metals and harmful organic chemicals.

This, according to the team, was not the case in lab settings where purified forms of water are used and do not feature the ions and impurities characteristic of tap water.

"Because tap water is not 100% pure H2O — since it contains trace elements and minerals, what we showed is that if you include these trace elements and minerals the degradation of plastics in tap water is completely different. Rather than the plastics falling apart, the minerals coat the plastic and prevent any kind of degradation and so the product becomes microplastic-free. For example, that dark brown color in your kettle is a good thing. It is copper oxide that forms from copper minerals in your tap water, which in turn comes from the copper pipes in your house — all these combine to give a perfect protection to the kettle," explained researchers.

As such, the team believes that protective skins inspired by this discovery could potentially be manufactured in lab settings and applied to plastic products rather than waiting for the barrier to naturally form over time.

Applications for such films could be for the development of films that behave like native biofilms, demonstrating emergent drug resistance, for instance, or having them serve as a model system for anti-biofilm drug development.

The study, Real-world natural passivation phenomena can limit microplastic generation in water, appears in the Chemical Engineering Journal.

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