A section of an Adelaide beach remains closed after a sludge spill from a water treatment plant raised contamination concerns.
About 300,000 litres of sludge flowed into Christie Creek, in Adelaide's south on Sunday, forcing authorities to close a 200-metre section of Christies Beach.
The incident was caused by a break-in with those responsible manually operating equipment in the treatment plant and causing the overflow.
Principal water quality adviser from SA Health David Cunliffe said testing of seawater had shown slightly elevated levels of contamination at the creek outlet, which could still pose a small health risk if people come in contact with the water.
He said the precautionary closure of a section of the beach to swimmers remained appropriate.
"The closure will remain in place until we can confirm there is no risk to the public, but we remind people, the access restriction only applies to swimming in this small part of the sea," Dr Cunliffe said.
"It's still entirely safe for people to walk along the nearby beach."
SA Water's acting senior manager of production and treatment Daniel Hoefel said crews had worked to clean up Christie Creek and to stop the spread of sludge into the ocean.
They used vac-trucks to pump the affected water from the creek, returning it to the treatment plant.
He said further samples of seawater had been taken with the results of those tests expected on Wednesday.
"We will also take the opportunity to review security arrangements at our major facilities, to make sure they remain fit for purpose," Dr Hoefel said.
The Christies Beach Wastewater Treatment Plant provides about 23 million litres of recycled water a day for toilet flushing and irrigation of agricultural areas in McLaren Vale and Willunga.
