Scientists Uncover What The Mysterious Black Tar Balls on Sydney Beaches Were
Image: Image: Raindwick City Council
A month after thousands of mysterious “tar balls” washed up along Sydney, stirring a mass confusion and the closure of several popular Sydney beaches, a team of scientists have finally unveiled their slimy composition — and it’s grosser than you think.
Scientists across disciplines form University of New South Wales have spent the past week sampling and analysing the black golf sized orbs which were first spotted in Coogee beach nearly a month ago and later across other beaches including Bondi, Bronte, Tamarama and Maroubra.
What are these black sticky “tar ball” blobs actually made of?
It was found that the ‘tar balls’ composition was actually much closer to “human generated waste” and not solely formed from oil spill run-off as originally diagnosed.
According to Associate Professor Jon Beves from UNSW’s Chemistry department, the materials that make up the ‘smelly’ balls are far cruder.
They contain almost a hundred different components, which includes molecules stemming from soap scum — more specifically all the post- shower dirt, oil and skin — and cooking oil, along with faeces, PFAS chemicals, steroidal compound, pesticides and even veterinary drugs.
Through radiocarbon dating it was found that the balls are made up of roughly 70 percent carbon and 30 percent fossil carbon. Professor Beves explained that modern carbon likely comes from carbon derived from plants and animals.
“The higher concentration of modern carbon at the surface may result from the loss over time of components that evaporate more easily,” he said.
UNSW Scientists find similarities between “tar balls” and “fatbergs” found in sewage systems
Further analysis of elements including an X-ray showed that the balls had “signifcant” levels of calcium present which might have helped bonding the organic components into stable, water-insoluble masses according to Professor William Alexander.
The analytical chemist also suggested that the presence fats, oils and calcium could mean the black balls are similar to “fatbergs” or solidified fat and grease (FOG) blobs typically found in sewage systems.
Despite these insights, the exact origins of the balls remain unknown. “Carbon-14 dating suggested they weren’t purely from an oil spill but contained markers of human faecal waste, THC, and industrial PFAS chemicals likely from sewage and other urban effluent origins” said Professor Donald.
Definitive origin of “tar balls” remains unknown
The NSW Environment Protection Authority (EPA) along with NSW Maritime, Randwick City Council and scientists are still further investigating the incident.
Sydney Water confirmed no issues were caused at Bondi or Malabar water facilities and Transport for NSW Maritime found no correlating weather anomalies for further explanation.
The origin of these sticky black blobs posing a threat to marine biodiversity remain unknown.
