ACID SULPHATE SOILS, Sydney Moore Park
Acid sulphate soils are a mix of low-lying coastal clays and sands that contain sulfur bearing compounds at concentrations
above 0.05% in clays and 0.01% in sands. Such soils are formed by the action of anaerobic bacteria on organic matter in the
presence of seawater. Thus, the distribution of these soils commonly reflects the past and present distribution of coastal,
estuarine wetlands. The sulfur bearing materials (generally in the form of pyrite) in the soil are the by-products of the
bacterial breakdown of wetland vegetation using sulfate compounds from seawater in the absence of oxygen.
Potential acid sulfate soils are generally found less than 5 metres above sea level. When drained these produce sulfuric acid which can move through the soil affecting groundwater and surface waters, and consequently, urban areas, farm productivity and fish. This is a major issue along the coastal fringe of NSW.
Within areas of acid sulfate soils many construction or engineering activities warrant an assessment of the risk exposing acid sulfate soils.
ADE’s team of geo-chemists and environmental scientists provide highly skilled services relating to Actual Acid Sulphate Soils. Some of these services include:
1. Preliminary Desktop Assessment involving:
- Establishment of characteristics of proposed works and whether they may impact upon Acid Sulphate Soils,
- Desktop review of Acid Sulphate Planning maps, risk maps and any relevant planning instruments,
- Consideration of soil and groundwater impacts if the proposed works are initiated,
- If site characteristics suggest probability of Acid Sulphate Soils an Acid Sulphate Soil Assessment is conducted.
2. Detailed Acid Sulphate Soil Assessment involving:
- Background review of site information and detailed site inspection,
- Drilling of boreholes by our own in-house drilling team,
- Installation of groundwater monitoring wells,
- Soil sampling at different depths and groundwater sampling,
- Screening of collected soil samples for pH and laboratory analysis of samples exhibiting the lowest pH for acid sulfate,
- Screening of collected groundwater samples for Dissolved Oxygen (DO), Electrical Conductivity (EC), pH, Redox potential and temperature and laboratory analysis for Chloride (Cl-) and Sulphate (SO42-),
- Cold storage of all samples collected,
- Preparation of a report outlining: (i) whether an Acid Sulphate Soil Management Plan is warranted, (ii) baseline groundwater characterisation and (iii) site data and recommendations.
3. Acid Sulphate Soil Management Plan
- A site-specific treatment strategy preventing the potential for on-site and off-site impacts,
- Some management strategies include: avoidance of soil disturbance, preventing the oxidation of sulphides, oxidation of sulphide and neutralising acid as it produced, separating out and treating the sulfidic component and burial below water table.
ADE employs the most cost-effective and environmentally benign methods. All ADE investigations and reporting are conducted in accordance with the Acid Sulfate Soil Manual published by the Acid Sulfate Soils Management Advisory Committee.
ADE maintains the highest standards of security when conducting environmental assessments. All the details of the investigations are strictly confidential.