Mystery of ‘disgusting’ black balls that closed Sydney beaches solved

Strange deposits were initially thought to be made of tar – but the truth turned out to be far more grim

When hundreds of golf ball-sized black balls mysteriously washed onto the beaches of Sydney, it caused enough alarm for the areas to be closed off to the public.
But what scientists initially thought was a strange combination of fuel oil, fat and chemicals has now been revealed to be far more “disgusting” than first thought.
Researchers from the University of New South Wales discovered that the balls were made of a combination of human faeces, cooking oil, chemicals and illicit drugs.
Following the discovery, which was made in October, local authorities closed a total of eight beaches for several days while a clean-up operation could be completed.
New South Wales’s maritime authority advised people that the balls should not be touched or picked up, with workers in hazmat suits collecting the deposits in plastic bags and sending them for testing.
“They smell absolutely disgusting, they smell worse than anything you’ve ever smelt,” said Jon Beves, associate professor and lead investigator.
Prof William Alexander Donald said: “I wouldn’t want to be swimming with them.”
Each ball was slightly different in shape, with a firm surface and a soft core. Testing determined that they were likely to be the result of a sewage spill, and not from an oil leak or ship waste, as was first believed.
Inside, researchers found a cocktail of faeces, methamphetamine, hair, cooking oil, blood pressure medication and a variety of other substances.
Despite the mystery blobs containing human faeces, Prof Donald said his team had a “lot of fun” analysing them.
“This was a significant analytical challenge, with highly complex mixtures containing hundreds to thousands of components,” he explained, adding that the presence of recreational drugs and industrial chemicals “pointed us to sewage and other sources of urban effluent”.
He said that the balls resembled smaller versions of the “fatbergs” that are commonly found in sewage systems.
Where exactly the balls came from and how they ended up on Sydney’s beaches is still unknown, scientists said.
“Unless you know where that waste source has come from, there’s no reason to think there couldn’t be more in the future,” warned associate professor Beves.
Sydney Water said there were no known problems with sewage systems in the city, and local authorities have now reopened the beaches.