Microplastics less than 5mm long pose threat to marine life, and come from clothing and toiletries

This article is more than 6 years old

This article is more than 6 years old

Researchers have found “alarming” level of plastic pollution in Sydney harbour, with fibres from clothing and toiletries causing a widespread impact upon the marine ecosystem.

The first information from the ongoing Sydney Harbour Research Program shows that small pieces of plastic measuring under 5mm have been found in each of the 27 surveyed sites along the length of the harbour.



Scientists from the Sydney Institute of Marine Science took sediment samples from the bed of the harbour and used a high salinity concentration to separate out the plastic.



Facebook Twitter Pinterest A map showing the distribution of microplastics in Sydney harbour. Map: Vivian Sim/University of NSW

The researchers found that the samples had 60 to 100 plastic particles per 100ml of wet harbour sediment. This is far higher than overseas sites – a study of a busy harbour in Sweden, for example, found 24 plastic particles per 100ml of sediment.



Thin plastic fibres, as opposed to shards of plastic bottles, were the most commonly found particles. These fibres come from clothing, such as fleeces that lose material as they are washed, and facial scrubs.

“The focus has previously been on larger pieces of plastic which injure turtles and birds, but it’s possible that microplastics are doing the most damage,” professor Emma Johnston, director of the research, told Guardian Australia.

“These plastics are small enough to be ingested by 96% of the world’s animals, invertebrates, which are then transferred to fish and larger animals.”

Facebook Twitter Pinterest The tiny plastic fibres can block the gut within fish. Photograph: Vivian Sim/University of NSW

The plastic fibres not only potentially block the gut within fish but also release toxins absorbed by the plastic after it is released into the environment.

Johnston, who started on the research project 18 months ago, is seeking funding for a further four-year analysis of the microplastics problem.

“This is cutting-edge research, so much so that we aren’t sure of the full impact of these plastics,” she said. “The lines of evidence all point to it being a major concern, but we don’t have the numbers to do a full risk assessment. We need to do a lot of targeted research quite quickly.”

Last year, research conducted by the University of Western Australia and the CSIRO found that the waters around Australia are riddled with more than 4,000 tiny pieces of plastic per square kilometre.

It’s estimated that Australia produces 1.2m tonnes of plastic each year.