Kangaroo Island Council will hire specialist consultants to determine the source of hydrocarbon pollution seeping into Christmas Cove at Penneshaw.
The consultants will look at the geology of the area and even possibly conduct test drilling to take samples.
The source of the petroleum-based contamination remains a mystery with the council and Environment Protection Authority both working to solve the mystery.
“We don’t know where it’s coming from but share the concerns of the community and want to find out the source,” KI Council chief executive officer Andrew Boardman said.
Both the council and EPA have undertaken inspections at the site, ruling out the current service station as a source.
Tests had been done on the contaminant and it has been found to be a “relatively young” petroleum based substance.
Mr Boardman said the council had even spoken to long-term residents to work out where there could be hidden fuel tanks.
“Because of the nature of the geology with sand and marl over harder black rock, the contaminant could be leaking from a kilometre or more away,” he said.
Hiring the geotechnical consultants and any remediation was going to be expensive and he warned that any private landowner could be up for a large bill if the source was found on their land.
Residents including Tony Coppins, who operates Kangaroo Island Ocean Safari, have expressed frustration that not enough is being done by either authority to solve the problem.
“This has been a pristine beach enjoyed by locals and tourists,” Mr Coppins said. “If this had been any other beach in Australia, it would have not been allowed to happen.”
He said the contamination seemed to coming from rubble dumped on the cove foreshore after dredging in 2004, but acknowledged it could be seeping from an old tank or dump site any distance away.
He noted that even the hooded plovers and oyster catchers had seemed to abandon the area.
An EPA spokesperson said the authority requested that the council install a remediation system, as well as undertake an assessment of the site to determine the source of the chemical substance.
“The results from this assessment determined that the substance was a hydrocarbon, however the source has not been identified,” the EPA spokesperson said.
“Further testing of the substance was undertaken in January 2018. The EPA will continue to work with the council to identify the source and determine an appropriate solution.”
The contamination first became evident after heavy rains at the end of 2016 when hydrocarbon-based material started oozing out the ground causing a petroleum smell and oil slick on the water surface.
The problem them seemed to disappear for some months before mysteriously appearing again and this time without rain.