New insight into Eastern suburbs beach ‘balls’

The NSW Environment Protection Authority has been working closely with NSW Maritime, Randwick City Council, and scientists to determine the origin of thousands of black balls that washed up on Eastern suburbs’ beaches earlier this month.

Extensive analytical testing, by the Department of Climate Change, Environment, Energy and Water and the University of NSW (UNSW) Science and UNSW’s Mark Wainwright Analytical Centre, has confirmed the balls comprised fatty acids, petroleum hydrocarbons, and other organic and inorganic materials. 

Fatty acids are natural substances that come from oils and fats, found in products like cooking oils, soaps, and skincare items. Petroleum hydrocarbons are chemicals from oil and gas products, such as gasoline, motor oil, and diesel fuel. 

Organic material refers to carbon-based substances that can naturally decompose, including items like hair, food waste and other plant and animal matter. The balls also contained inorganic material such as sand, calcium salt and bacteria which are commonly associated with wastewater. 

The investigation has revealed that the balls contain hundreds to thousands of different materials, including human hair and various fibres, indicating they likely originated from a source that releases mixed waste.  

Authorities have considered several possible causes, such as a shipping spill or wastewater outflow. However, due to the complex composition of the balls and the time they have spent in the water, testing has not been able to confirm their exact origin. As a result, authorities have so far been unable to trace the source, but final results are due in the coming weeks.    

Sydney Water confirmed soon after the balls were reported that there were no issues with the operation or maintenance of the Bondi or Malabar water resource recovery facilities. 

Transport for NSW Maritime closely examined weather patterns in the days leading up to the event, but nothing conclusive could be determined from this analysis.