Coastal Acid Sulfate Soils
This page deals specifically with coastal acid sulfate soil and it's creation under marine/estuarine conditions. Other acid sulfate soils found around Victoria can be associated with mineral ores, peats and inland water ways.
Coastal acid sulfate soils and sediments are the result of the accumulation of metal sulfides (usually iron sulfides). This occurs under waterlogged or highly reducing (anaerobic) conditions where organic matter, sulfates and metal ions are all present. Such conditions are typically found in the estuaries, lakes, lagoons, marshes, morasses and swamps along Victoria’s coast. Such conditions can also be found in the flood plains of these water bodies and water ways. These conditions can also occur in coastal dunes and the plains behind them.
As long as acid sulfate soils remain waterlogged or oxygen free, they are harmless. Any disturbance in which oxygen enters the soil (e.g. drainage, de-watering) creates a chain of reactions which causes the soil to acidify to pH 4 or less, i.e. un-naturally acidic as most soils are pH 4 to pH 9. Water leaching from disturbed coastal acid sulfate soil can be highly acidic too.
Prospective Land: land that has the potential to contain Acid Sulphate Soils
Research is being conducted by DPI and DSE, to improve our knowledge of where land that has the potential to contain Coastal Acid Sulphate Soils, occurs along Victoria’s coast. This new research is based on a more detailed analysis of coastal geomorphology, and on additional soil sampling, than was previously available to the pilot study reported by Rampant et al. (2003). Current results are studied using the links immediately below. These maps are subject to change without notice, as new information becomes available. These maps update the previously available acid sulfate soil hazard maps produced by Paul Rampant and co-workers. However, their report and their maps are provided below as an historical reference.
To view the information PDF requires the use of a PDF reader. This can be installed for free from the Adobe website (external link).
 Far South West Coast (from Peterborough) (PDF 168KB) |  West Coast (from Peterborough to Torquay) (PDF 253KB) |  Central Coast (from Torquary to San Remo) (PDF 379KB) |
 South Coast (from San Remo to Seaspray) (PDF 224KB) |  East Coast (from Marlo to Mallacoota) (PDF 190KB) |
The report on a pilot study of Victorian coastal acid sulfate soils produced by Rampant et al., (2003), is available for download below. The maps from this report are available by clicking the map to the right. |
 | (PDF 939KB) To view the information PDF requires the use of a PDF reader. This can be installed for free from the Adobe website (external link). |  Gemco sampling rig in operation. This was used to mechanically extract samples to a depth of 5 metres. |
 | Hand Augering for acid sulfate soils close to Melbourne. Note the grey and black layering typical in the soils from this environment . Often there may be layers of shell (sometimes up to 70%) within the profile. Hand augering to 4-5 m was quite common during this study. |
 | The straw-coloured material in this black clay is the mineral Jarosite. Jarosite is evidence that there is oxidised acid sulfate soils. It is found in places where the ASS has been disturbed (excavated or drained) so that the previously inundated ASS layers have been exposed to air. This shows the typical Jarosite formation in drained soil: first appearing along the root channels. This sample was taken from South Melbourne. |
Related Links
- The new strategy on Coastal Acid Sulfate Soils in Victoria (external link), can be found on the DSE website. The strategy explains why CASS is a management issue in Victoria. The strategy helps land owners, and land and water managers to avoid disturbing CASS.
- Acid Sulfate Soil and Rock (external link). Downloadable document on the EPA Victoria website.
- Information about Acid Sulfate Soils (external link) on the Queensland Department of Natural Resources, Mines and Energy website.
- Information about Acid Sulfate Soils in NSW - on the NSW Agriculture website. Includes information on: distribution of acid sulfate soils in NSW; National Strategy for Acid Sulfate Soils; ASS Local Environment Plans; ASS Manual and Newsletters.
- Information about Acid Sulfate Soils in NSW - on the NSW Department of Land and Water Conservation website. Includes information on distribution of ASS; causes of acid sulfate soil oxidation; effects of acid sulfate soils; management and remediation of ASS in NSW; online technical papers.
- Information about National Coastal Acid Sulfate Soils (external link) - on the Environment Australia website.
- Information on Coastal Acid Sulfate Soils is available on Geoscience Australia's OzEstuaries website (external link). This page also has links to other relevant sources of information.
- The Western Australian Planning Commission website provides downloadable Planning Bulletins (external link) - to provide advice and guidance on matters that should be taken into account in the rezoning, subdivision and development of land that contains acid sulfate soils in WA.
- Information about Acid Sulfate Soils (including mapping, identification and impacts) (external link) is available on the Queensland Government's Department of Natural Resources and Water website.
© The State of Victoria, 1996 - 2009.
This document was last reviewed on 03/09/2009