A risk assessment report is being prepared for the site’s owner, Newcastle City Council.

Newcastle Greens councillor Michael Osborne said he was so concerned about the contamination risk that he believed the 38-hectare site needed to be fully excavated and re-filled.

It is estimated about 3million tonnes of waste was buried at depths of up to five metres on the site between 1972 and 1995.

Previous testing has identified the presence of petroleum hydrocarbons, non-metallic inorganics and metals.

The former tip site is at the end of Astra Street near Sandgate railway station and next door to Ironbark Creek and the Shortland Wetlands.

Cr Osborne said he believed the contaminants would now be leaching into the wetlands area.

‘‘The job [rehabilitation] needs to be done properly. It’s not good enough to have this sitting next to an internationally recognised wetland,’’ he said.

‘‘Yes, it will cost money but it’s an investment we need to make for future generations.’’

University of Newcastle chemical engineer John Lucas, who has developed technology to treat contaminated land, said the installation of a reactive barrier that allowed water but not pollution to flow through it, was a possible solution.

‘‘We should never have built a tip next to a wetland in the first place, but we did,’’ Associate Professor Lucas said.

‘‘Now we have a problem that has a very difficult solution. Whatever solution you choose will be very expensive.’’

An Environment Protection Authority spokeswoman said the old dump was under the authority’s regulation, although the land was owned by Newcastle City Council.

‘‘Council has advised the EPA that a report about the Astra Street site, based on the latest round of ground water monitoring, accompanied by a risk assessment is currently being prepared,’’ she said.

‘‘The EPA will be assessing that submission to determine whether the risks from the site have been addressed.’’ 

mkelly@theherald.com.au