Black balls on Sydney beaches test positive for human waste

Mystery balls that washed up on Sydney’s northern beaches last week have tested positive for human-generated waste — similar to those that appeared on the city’s eastern beaches last year.

The latest discovery of white globules, ranging in size from tennis balls to beach balls, led to the closure of nine beaches from Manly to North Narrabeen on January 14.

In October 2024, black balls that washed up on beaches from Bondi to Botany Bay were initially thought to be "tar balls". However, testing by the New South Wales Environment Protection Authority revealed they contained human-generated waste, including fats, oils, calcium, pesticides, human hair, hypertension medication, animal drugs, steroids, THC from marijuana, and methamphetamine.

While the source of the contamination remained unclear, experts believed Sydney’s sewage system might be to blame.

Sydney’s wastewater underwent only "primary" treatment at plants in Bondi, Malabar, and North Head before being discharged into the ocean via deepwater outfall pipes located between 2km and 4km off the coast. These pipes, built in the 1990s, were designed to handle wastewater disposal but might be contributing to the pollution.

Another potential explanation was illegal dumping into the wastewater or stormwater systems.

Sydney Water was investigating the matter and said it had a $30 billion, 10-year plan to upgrade the city’s wastewater networks.