Sydney beaches and rivers contain high levels of microplastics, scientists find



Kilos of tiny particles of plastic smaller than 5 millimetres are being found across Sydney’s beaches and rivers, highlighting the scale of the threat to local marine life and the risk to human health, scientists say.

Beaches like Dee Why and Watsons Bay are described as “hotspots” with levels as high as 1,000 microplastics per square metre, the Australian Microplastic Assessment Project (AUSMAP) has found.

But citizen scientists are being enlisted to help find out where the plastics pollution originates and how to contain it, through AUSMAP’s global-first nationwide research project.

Volunteers at Manly Cove found 11.87 kilograms of plastic debris like broken-down bottle tops, cigarette butts and textile fibres during a collection in February.

Most people have no idea that plastic in everyday use can break down to such small particles through wear and tear, Scott Wilson, a research director at AUSMAP, said.

A tiny bottle with plastic fragments inside with a beach in the background.
Some of the tiny plastics being found on Sydney beaches.(Supplied: AUSMAP)

“So obviously it is cause for concern, when you’ve got these high [levels of] plastics, then you know they are a potential source for harm to a local marine life or freshwater life,” Dr Wilson said.

“But also, potentially if we’re consuming those species, then there’s movement potentially up to humans.”

Some of the hotspots include Botany Bay and the mouth of the Cooks River, locations around Chipping Norton and Liverpool on the Georges River.

A map of Sydney with red, yellow and green circles in different locations.
Hotspots around Sydney shown in red from microplastic sampling in 2019.(Supplied: AUSMAP)

‘An eye opener’

Dee Why lagoon on Sydney’s northern beaches is the site of a wetland, important as a migratory bird breeding ground and for marine invertebrates.

To try and stop plastics leaching into the local stormwater drains, mesh baskets have been installed with fine enough wire to collect the tiny particles.

A wire basket on grass next to a drain.
This mesh basket was installed into a stormwater drain at Dee Why on Sydney’s northern beaches.(Supplied: AUSMAP)

Volunteers taking part in the research find that once people see what’s being found, it is an eye-opener, Dr Wilson said.

“At Dee Why people were just walking by and we said, ‘You want to come and look at what’s washing off your street?'” he said.

“And once they saw they just couldn’t believe how much is there in such small sizes.”

A beach with plastic collecting materials and a red flag.
Manly Cove reveals some of the highest microplastic levels in Sydney.(Supplied: AUSMAP)

Researchers have been gathering data since 2018 about locations all over the Harbour City, and Dr Wilson said things were turning around slowly.

He points to the federal government’s recent plastics plan and manufacturers’ moves to introduce filters in washing machines to collect fibres.

People sift sand on a beach.
Volunteers are working at numerous sites around Sydney, collecting important long-term data.(Supplied: AUSMAP)

At Bondi, the level of microparticles found was on the lower end of the scale, with 203 microplastics found per square metre.

Council workers and volunteers took part in AUSMAP’s training so they could try to help minimise the impact of fish and birds ingesting microplastics, Waverley’s Mayor Paula Masselos said.

“The variety of microplastics that volunteers managed to find at Bondi Beach in just a short amount of time was a sobering reminder of the need to limit single-use plastics and dispose of litter correctly at all times,” she said.


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