More than 1000 wetlands throughout the Murray-Darling Basin, including 16 RAMSAR-listed sites, will be assessed to determine the risk posed to them by acid sulfate soils, the Murray-Darling Basin Commission has announced today.

MDBC chief executive, Dr Wendy Craik, said the project, while funded by the MDBC, would be carried out by State agencies, the Murray-Darling Freshwater Research Centre, CSIRO, Southern Cross University and several catchment management authorities.

"The project has been given a high priority, particularly given the scale of this issue and nature of the threats in South Australia's Lower Lakes," Dr Craik said.

The project will assess the extent of, and risk posed by, acid sulfate soils at key wetlands in Queensland, News South Wales, Victoria and South Australia.

"The sites have been selected because of their environmental significance," Dr Craik said.

"They include the 16 Ramsar listed wetlands in the Basin, as well as those listed on the Directory of Important Wetlands in Australia and other environmentally significant wetlands.

"Other sites have been chosen where there is an increased likelihood of acid sulfate soils developing which could impact on the surrounding environment and water supplies."

Acid sulfate soils are soils containing iron sulfide minerals.

These soils form naturally when saline groundwater or other water containing sulfate mix with sediments which contain iron oxides and organic matter.

When undisturbed and not exposed to air these soils pose little threat.

But due to the drought river levels have dropped and many wetlands have dried out, leaving long-submerged soils and sediments exposed to the air, thus creating the potential for sulfuric acid production.