Tiny pieces of plastic that pollute the environment can be produced by simply opening a plastic bottle or tearing a food wrapper.

Microplastics are between 0.001 and 5 millimetres in size and are usually either produced directly, or form when large plastic debris breaks up. We now know that millions of tonnes of microplastics are abundant in the environment and can harm marine life by entering the food chain. Microplastics are also found in our food  although the effect on human health is still unclear.

Cheng Fang at the University of Newcastle, Australia and his colleagues tested whether everyday activities could release microplastics. They opened common plastic items such as bags, bottles and packaging film by twisting the bottle cap or tearing the bag, for example, or by cutting them with scissors or a knife, which deforms and fractures the plastic.

The team used a scale that is sensitive to weights as low as one nanogram to collect and measure the microplastics that landed on its surface. Between about 10 and 30 nanograms of microplastic were released from opening the plastic items, which amounts to between 14,000 and 75,000 individual microplastic particles. But the team says that the true amount released is probably even higher, because many microplastics are statically charged and remain in the air.

Studying the microplastics with a microscope revealed that most were in the form of fragments or fibres of varying shape and size. Some could be seen with the naked eye, such as those from cutting bottles. The team also used a technique called spectroscopy to deduce the microplastics’ chemical composition and found the majority were made of polyethylene, one of the most widely used plastics.

“This finding sends an important warning,” says Fang. “We might need to take our own responsibility and work with industry together to reduce [microplastics].”

Comment from Christian Dunn at Bangor University, UK: : “I’d love to say that I’m surprised and shocked at the results, but unfortunately, I’m not and you are  not. We’re now realising that microplastics are literally everywhere.   It is now crucial that we work to find out their  possible health effects, and cut back on unnecessary plastic use”.  (Gege Li, March 28 2020)Journal reference: Nature Scientific Report. DOI: 10.1038/s41598-020-61146-4)