Experts solve mystery of smelly Sydney beach blobs

The mystery blobs were first spotted on a Sydney beach in October

When sticky dark blobs first started washing up on some of Sydney's beaches last month, experts were puzzled.

Initially it was thought that the balls were made of tar which could have come from an oil spill.

Researchers in Australia decided to carry out tests to find out exactly what the mystery spheres contained.

They've now discovered that the blobs are made up of a mixture of chemicals, cooking oil..and human poo.

What happened?

The black objects were first spotted by lifeguards at Sydney's Coogee Beach three weeks ago.

They also then started popping up on some of the other beaches in the city - in fact thousands of them started to appear.

As a result, eight beaches, including Sydney's famous Bondi were closed for several days and a massive clean-up operation was ordered.

Each blob was dark in appearance and slightly different - but they all had a firm surface.

Experts were sent in to try and find out what the strange blobs were and where they had come from.

Lead investigator Associate Professor Jon Beves, from the University of New South Wales (UNSW) told 9News: "They smell absolutely disgusting, they smell worse than anything you've ever smelt."

When researchers first started looking into the blobs, they thought that the balls had most likely come from a sewage spill.

Further testing found the blobs were unlikely to have only been the result of an oil spill or waste from a ship, as some had thought.

Instead, they discovered that inside the balls was a mix of lots of different things including cooking oil, chemicals, soap, hair and poo.

Professor William Alexander Donald, from UNSW added that the balls looked like fat, oil, and grease blobs - often called fatbergs - which are often formed in sewage systems.

However, Sydney Water, the company responsible for water in the area, has said that there are no known issues with waste systems in the city.