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.
- Researchers say hotspots in Sydney include Dee Why, Botany Bay, Cooks River, Chipping Norton and Liverpool
- The highest in Sydney was at Manly Cove, where 4,000 microplastics per square metre were found
- Volunteers are finding solutions like mesh baskets in stormwater drains can prevent waterway pollution
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.
“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.
‘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.
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.”
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.
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.