The contents of mysterious grey balls washed up on Sydney’s Northern Beaches have now been identified after nine beaches were closed due to the pollution spheres.

The mysterious balls that forced the closure of several beaches in Sydney last week were found to contain saturated acids, E. coli and faecal bacteria, authorities say. Sydney's Northern Beaches council said it has sent the debris to the New South Wales Environment Protection Authority (EPA) for further analysis.

Australian authorities have closed nine beaches in Sydney due to mysterious balls washing up from the ocean. These balls, consisting of an unknown substance, appeared on the beaches on Tuesday morning.

Mysterious polluting spheres that closed nine northern beaches contain similar contents to the “tar” balls that appeared across the eastern suburbs last year, according to preliminary test results released on Monday.

According to The Guardian, several marble-sized balls have washed ashore on nine beaches located in Sydney, Australia. The debris is peculiar in appearance, with a white or grey exterior and a flaky, dark-colored center. Other than appearing organic in nature, they aren’t easily identifiable.

Swimmers and surfers were urged out of the water on Tuesday afternoon after the white-grey, ball-shaped debris was found along Sydney's northern beaches.

Sydney: Australian authorities closed nine Sydney beaches on Tuesday after mysterious white and grey balls washed up along the coast. Beaches

Sydney’s pumping of primary-treated effluent into the ocean makes us out of step with the rest of the world, a water engineering expert said.

Several popular beaches in Sydney, including Manly and Dee Why, were closed recently due to the sudden appearance of mysterious small balls washing ashore. Also read Mysterious Balls Close Sydney Beaches Once Again as Authorities Investigate Now the Northern Beaches Council confirms that the balls contained saturated acids,