Nanoplastics produce unexpected reactions when exposed to light

Context

A team of researchers has analysed how light breaks down polystyrene, a non-biodegradable plastic from which packing peanuts, DVD cases and disposable utensils are made.

Findings

When exposed to light, the nanoplastics derived from polystyrene unexpectedly facilitated the oxidation of aqueous manganese ions.
The formation of manganese oxide solids that can affect the fate and transport of organic contaminants in natural and engineering water systems.
It showed how the photochemical reaction of nanoplastics through light absorption generates peroxyl and superoxide radicals on nanoplastic surfaces, and initiates oxidation of manganese into manganese oxide solids.

Nanoplastics are particles unintentionally produced (i.e. from the degradation and the manufacturing of the plastic objects), within the size range from 1 to 1000 nm.

Concern associated:

There are concerns over the physical presence of nano-plastics rather than their active roles as reactants.
The small plastic particles that can more easily interact with neighbouring substances, such as heavy metals and organic contaminants, and can be more reactive.
The smaller particle size of the polystyrene Nano-plastics may more easily decompose and release organic matter because of their larger surface area.
This dissolved organic matter may quickly produce reactive oxygen species in light and facilitate manganese oxidation.