Acid sulfate soils assessment services
Identifying and managing acid sulfate soils before disturbance turns them into an environmental problem.
Acid sulfate soils are naturally occurring soils and sediments containing iron sulfides that remain harmless while waterlogged but generate sulfuric acid when exposed to air through excavation, drainage, or dewatering. That acid can damage infrastructure, kill vegetation and aquatic life, and mobilise metals into waterways. Environmental Specialists Australia assesses whether a site contains acid sulfate soils, tests their potential acidity, and prepares management plans that let works proceed without triggering these impacts.
These soils are common in low-lying coastal and estuarine areas across Australia, and their disturbance is regulated through planning instruments and state guidelines that map risk areas and set assessment triggers. Our consultants check risk mapping, design sampling to confirm the presence and reactivity of acid sulfate soils, and interpret results against recognised action criteria. Where management is required, we prepare acid sulfate soils management plans setting out handling, neutralisation, and monitoring measures suited to the site and the scale of disturbance proposed.
When is this service required?
- Earthworks or excavation in low-lying coastal, estuarine, or floodplain areas
- Development applications on land mapped as having acid sulfate soil risk
- Dewatering or drainage works that could lower the water table into sulfidic layers
- Dredging or works in or near waterways and wetlands
- Projects where a consent authority requires an acid sulfate soils assessment
Our process
- Risk mapping review: Review of acid sulfate soil risk mapping and the proposed works to determine whether assessment is triggered.
- Field investigation: Soil sampling at depths relevant to the disturbance, with field screening to guide the program.
- Laboratory testing: Analysis of samples for actual and potential acidity using recognised acid sulfate soil methods.
- Assessment against action criteria: Comparison of results with action criteria to determine whether management is required.
- Management planning: Preparation of an acid sulfate soils management plan covering handling, neutralisation, and monitoring.
What we deliver
- Acid sulfate soils risk assessments
- Soil sampling and analysis programs
- Laboratory testing of actual and potential acidity
- Assessment against recognised action criteria
- Acid sulfate soils management plans
- Handling, neutralisation, and monitoring measures
Frequently asked questions
- How do I know if my site has acid sulfate soils?
- The first indicator is risk mapping in the relevant planning instrument, which flags land where these soils are likely. Low-lying coastal, estuarine, and floodplain land below a few metres in elevation is most at risk. Confirmation requires field sampling and laboratory testing of actual and potential acidity.
- Why are acid sulfate soils a problem only when disturbed?
- While the soils stay waterlogged, the iron sulfides they contain are stable and inert. Excavation, drainage, or dewatering exposes them to oxygen, which generates sulfuric acid. That is why the assessment focus is on the depth and volume of soil your works will disturb or expose.
- What does an acid sulfate soils management plan cover?
- It sets out how disturbed material will be handled to avoid acid generation — typically neutralisation with lime, controlled stockpiling, drainage management, and monitoring of soil and water. The plan is scaled to the works so measures are proportionate to the volume and reactivity of the soils involved.
- Will an assessment delay my project?
- Not if it is planned early. A sampling round and reporting can usually be completed within a few weeks, and identifying the issue up front avoids the far larger delays that follow if acid soils are disturbed without a plan and works are stopped by the regulator.