Coastal acid sulfate soils

Acid sulfate soils are widespread along our estuarine floodplains and coastal lowlands. Photo: Mitch Tulau.
Acid sulfate soils are widespread along our estuarine floodplains and coastal lowlands. Photo: Mitch Tulau.

Coastal acid sulfate soils are naturally occurring sediments that are deposited under estuarine conditions. They contain iron sulfides, most commonly as pyrite, and/or the products of iron sulfide oxidation.

When exposed to oxygen through drainage or disturbance, these materials produce sulfuric acid, often releasing toxic quantities of iron, aluminium and other metals.

Coastal acid sulfate soils are widespread along the NSW coast. They occur in mangrove flats, salt marshes and tea-tree swamps, and underlie coastal floodplains, including farmland and urban areas.

Because of its estuarine origin, coastal acid sulfate soil material is only found at very low elevations, generally less than 1 metre above sea level.

OEH management 

The OEH role in managing acid sulfate soils includes:

Contact us

Email acidsulfatesoils@environment.nsw.gov.au for:

  • key documents, or
  • general information or technical advice about coastal acid sulfate soils.

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Page last updated: 28 October 2013