Questions are being asked about the levels of waste that a mining company is licenced to release into a Wollongong creek.

Water scientist Ian Wright from the University of Western Sydney says the South32 Dendrobium Mine is allowed to dump “inappropriate” discharge containing nickel, zinc, copper, arsenic and cobalt that “exceed safe levels”.

The company trucks 6 to 8 thousand of litres of brine waste water over 40 kilometres from the mine to Allens Creek, making the run up to 17 times a day.

South32 says it is operating within official boundaries.

“All of our recent monitoring at Allens Creek has shown that the substances we test for were at levels beneath the thresholds permitted by the NSW Environment Protection Authority,” a spokesperson told reporters.

Dr Wright says “the biggest surprise” is that the NSW Environment Protection Authority “actually permits this discharge at this sensitive point”.

“The conditions in that licence allow for very, very dangerous levels of those pollutants,” he told the ABC.

Dr Wright says the conditions do not cover cobalt at all.

“As it has accumulated at very high concentrations in Port Kembla inner harbour and outer harbour, and Allens Creek itself,” he said.

“The elevated levels contribute to an estuary already containing elevated levels in the sediment.

“Their EPL licence does not name cobalt.”

The NSW EPA says South32’s “licence does not allow ecologically hazardous discharges into Allens Creek”.

“Cobalt is not on the licence because monitoring has shown its it not elevated downstream of the discharge in Allens Creek,” the department said.