What were initially thought to be tar balls from an oil spill, which washed up on Sydney beaches in October, have subsequently been found to be a noxious mixture of human faeces, methamphetamine, and PFASs (“forever chemicals”). A detailed composition analysis suggests they may have broken off a giant “fatberg” out at sea before washing ashore.
Reports of the phenomenon first started appearing on Oct. 16, when lifeguards on Coogee beach reported numerous black spheres on the sand that appeared to be tar.
Preliminary testing by Randwick Council confirmed they were consistent with tar balls made up of oil and debris.
Other sightings were soon reported at nearby Bondi, Bronte, Tamarama, and Maroubra beaches.
As health authorities believed the tar could be toxic, they had ordered the beaches closed, issued public health warnings, and commenced cleanup efforts.
However, a team of scientists from University of New South Wales (UNSW)—led by Jon Beves and William Donald, associate professor and professor of chemistry, respectively—set out to discover the true composition of the mystery objects and where they came from.
Although initial testing suggested the material resembled unrefined oil, “further testing indicated a different, more disgusting, composition,” the researchers said.
Spectroscopic tests showed components of the black balls included fats, oils, and greasy molecules often found in soap scum, cooking oil, and food sources.
“This pointed to human waste,” they said.
They next tried dissolving the balls, but only about a third of their total mass was broken down by the various solvents they tried. That was enough to run more detailed tests, which led to the discovery of PFAS or “forever chemicals,” along with steroids, blood pressure medications, pesticides, and even veterinary drugs.
“This is consistent with contamination from sewage and industrial runoff,” they surmised.
“There were also signs of human faecal waste, including a cholesterol byproduct ... and residues of recreational drugs including tetrahydrocannabinol (also known as THC, a compound found in the cannabis plant) and methamphetamine.”
Origin Unknown
While the composition of the black balls suggests they may be similar to fatbergs, Beves and Donald said they can’t definitively confirm their exact origin.“The black ball incident does highlight the broader issue of pollution along Sydney’s coastline,” they pointed out.
“Recent reports indicate about 28 percent of monitored swimming sites in New South Wales (NSW) are prone to pollution. Many receive poor water quality ratings, especially after rain.
While the NSW Environmental Protection Agency (EPA) said they had considered several possible causes including a shipping spill or wastewater outflow, but the “complex composition” of the balls meant they were unable to confirm their exact origin.
When the balls were first discovered, Sydney Water said there were no issues with either the Bondi or Malabar water resource recovery facilities.
Transport for NSW’s maritime division examined weather patterns in the days leading up to the event, but nothing conclusive could be determined.
Among the possible origins are that they came from the local sewer system or been discharged from a boat, or washed from the sewers into stormwater drains and then to the ocean.
NSW Environment Minister Penny Sharpe said investigations were continuing to establish the source of the pollution and who was responsible.
