Brisbane’s two most famous streams have more than 4000 small pieces of plastic per kilogram of sand, causing a serious health threat, new research has found.
Queensland University of Technology researchers dredged mud from the Kedron Brook, Enoggera and Bulimba streams four times a year in 2024, and approximately 4400 plastic particles were found in one kilogram of Kedron Brook sediment.
About 4100 particles were found in the same level of Bulimba Creek mud, while Enoggera was the cleanest of the three, with 2800 pieces of plastic per kilogram.
Microplastics are everywhere and can be found in water, land and air. As a result, broken down plastics have been detected in all types of human tissue, and while the health threats are not fully understood, it has. has been linked to colon and lung cancer.
PhD candidate Heshani Mudalige said the amount of plastic found in Brisbane’s three streams depends on the slope, seasons, and where the stream flows.
“Kedron Brook’s low plastic load is greatly affected by its operation in commercial and industrial areas, including the Brisbane Airport area,” he said, noting that the brook’s highest load was in March following heavy summer rains.
Mudalige said the impervious areas in the Kedron area may have brought much smaller plastic into the creek.
He said Enoggera probably had a lower load because the flow of the stream was controlled by the dam.
Mudalige said a 2021 study on the Brisbane River found about 500 pieces of plastic per kilogram of sediment.
He said it is the first time that Kedron Brook sediments have been tested for microplastics.
Associate Professor Prasanna Egodawatta said the study would stimulate future research into how microplastics moved through Brisbane’s urban water systems.
“This study is the first step towards assessing the small terrestrial inputs to Moreton Bay through the storm water channel,” Egodawatta said.
While the three streams do not flow into water treatment plants that can lead to human consumption, Mudalige said the plastics can still pose a danger if they reach the sea.
The results of the QUT study were published in the journal Environmental Pollution.
Mudalige is also working to monitor the amount of PFAS “permanent chemicals” and heavy metals in three streams, and the papers will be published in the near future.
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