Lifeguards declared Sydney’s famed Bondi beach and several other strands closed Thursday, as more mysterious black “tarball” globules washed up along the city’s shores. Hundreds of the golf-to-baseball-sized spheres appeared on Coogee and Gordons Bay beaches, which were shut to swimmers, while residents and tourists were left to wonder just what they were. Local officials said chemical testing identified the floaters as hydrocarbon-based tar balls.
“Tar balls are formed from oil floating in the ocean,” said the Australian Environmental Protection Agency spokesperson. “The weathering process changes the oils into a sphere.” The debris is similar to tar patties, which are complex and crusty on the outside and soft and gooey on the inside. Turbulence in the water or beach activity can break open tar balls and patties, exposing their fluid centers.
The spokesperson added that the spheres could pose health risks if people touched or consumed them. The tar balls may contain toxic chemicals such as benzene, which can be carcinogenic or poisonous if inhaled. The EPA has asked local authorities to test for contamination.
While the exact cause of the tar globules is unknown, the spokesperson added that the oil likely came from a ship or a slight run-off. The round nature of the globules suggests they have been buffeted and smoothed at sea for months. The spokesperson said linking them with a significant oil spill would be difficult. “There are many different ways that oil can wash up on the coast, from a shipwreck to a dredge that’s been broken loose,” she said.
It’s also possible that the tar balls have come from afield. “The south, north, and east of NSW have been having a lot of rain, and that may have washed some up on those beaches,” she added. “Then again, they could just be coming from the wider Pacific Ocean.”
The tar globules have been spotted as far south as Botany Bay, where officials warned that more beaches could close if the contaminant continues to wash ashore. NSW Maritime is trying to determine where the tar originated by conducting reverse and drift modeling. It will also consider wind, currents, and weather conditions to determine what caused the tar balls to wash up on Coogee and other beaches. “We’re confident we can work out where it has come from and, if necessary, take appropriate action,” the spokesperson said.