Managing acid sulfate soils

The easiest and most effective way to avoid the harm caused by acid sulfate soils is to leave them alone—so identification and mapping are important. Avoiding acid sulfate soils is encouraged when possible.

However, acid sulfate soils are common in places where humans live, and sometimes construction in and around these sediments cannot be avoided. In such cases, the first step is to minimise the level of disturbance as much as possible.

Minimising disturbance

Minimising disturbance can be quite easy, and may involve:

• designing a construction project that limits the amount of excavation—for instance, building an above-ground car park instead of a basement, building smaller structures on stilts or push-piles, or placing clean fill in a thick layer before building
• locating a construction project on the part of a property where acid sulfate soils are buried deepest, so the amount of acid sulfate soil removed is reduced
• using construction methods and site management procedures that don't leave acid sulfate soils exposed to air without treatment
• aligning and designing linear infrastructure in tidal areas so that natural water flows (both surface and groundwater) are not blocked
• making farm and urban drains broad and shallow so they don't dig into buried acid sulfate soil layers, but can still remove excess surface water efficiently.

Treatment

If acid sulfate soil is disturbed, it must be treated.

The most common method of treatment is to mix an alkaline material into the soil, where it can react with acidity and neutralise it. Agricultural lime (powdered calcium carbonate—CaCO₃) is the most common neutralising material in use.

While minimising and avoiding disturbance can be easy, managing it is complex and should be done by appropriately trained people.

More information

• Read our best-practice guidelines to find out more about managing acid sulfate soils in Queensland.
• Read more on available acid sulfate soils mapping for Queensland.