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.

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.