Accurate identification is the first step in management of acid sulfate soils. Early identification of ASS and confirmatory laboratory analysis can provide an excellent platform for development and adoption of effective best management practices for a site underlain by ASS.

Potential Acid Sulfate Soils (PASS) are soils containing iron sulfides (commonly pyrite) which have potential to produce sulfuric acid if drained or excavated. PASS can be identified in the preliminary stages by the field test, pHFOX, and confirmed through laboratory analyses using the POCAS method or SCR method.

Actual Acid Sulfate Soils (AASS) have already undergone oxidation to produce acid. This results in an existing low soil pH (pHF <4) and often a yellow and/or red mottling in the soil profile. If these soils still contain sulfides, they have potential to produce more acid if allowed to oxidise further. This would be identified by a further decrease in pH reflected in the pHFOX. AASS also require confirmatory laboratory analyses.

Collective evidence - Some indicators are more conclusive than others. Jarosite is one of the most conclusive field indicators of ASS. Generally, the more indicators present at a site, the more confidence there can be in positively identifying ASS. Accurate and early identification is integral to developing sound strategies to manage ASS ‘hot spots’. This in the long term is likely to reduce costs associated with unnecessary disturbance.

Review of the relevant Acid Sulfate Soil Risk Map (1997) developed by the Department of Land and Water Conservation (DLWC) is typically undertaken. If the maps indicate that the site is located in an area deemed not to be effected by acid sulfate soils, and the site is not located in an area commonly found to contain acid sulfate soils, then a conclusion may be drawn that the proposed development is not likely to be impacted by acid sulfate soils.

If, in contrast, the maps indicate a potential for acid sulfate soils, reference is made to the Acid Sulfate Soil Manual, developed by the Acid Sulfate Soil Management Advisory Committee (1998), which provides recommendations for further assessment, depending upon the likely severity of acid sulfate soils.

Environmental Investigations has expertise in the assessment and management of acid sulfate soils, including:

Field assessment of potential and actual acid sulfate soils;

Handling treatment and disposal of acid sulfate spoil;

Assessment and management of water quality impacts;

Management of areas affected by acid sulfate soils and remediation of affected sites; and

Development of acid sulfate soil environmental management plans.