Acid Sulfate Soil Managment
Acid Sulfate Soil Remediation & Management
Acid Sulfate Soils (ASS) are commonly located in wet, anaerobic environments characterized by low oxygen levels, often referred to as 'reducing' conditions. These soils are prevalent along much of the New South Wales coastline, as well as within inland river systems and swamp areas. In their natural state, ASS are stable and non-reactive, as the lack of oxygen prevents the sulfide minerals contained within them from undergoing chemical changes.
However, these soils can become disturbed through various human activities, such as excavation, large-scale drainage projects, or groundwater dewatering. When these activities occur, sulfide minerals are exposed to the atmosphere, introducing oxygen to the soil. This exposure initiates the oxidation process, where the sulfides react with oxygen to form sulfuric acid. The generation of sulfuric acid can have significant environmental consequences, leading to soil and water acidification, which can negatively impact local ecosystems, water quality, and vegetation health.
Effective management strategies are essential to mitigate the risks associated with Acid Sulfate Soils. This may involve careful planning and assessment before undertaking construction or land development activities in areas where ASS are present, as well as implementing measures to control or prevent the oxidation process during and after excavation. By understanding the behavior of these soils and taking appropriate precautions, we can minimize their environmental impact and ensure sustainable land use practices.
Acid Sulfate Soil Remediation & Management
Acid Sulfate Soils (ASS) are typically situated in wet, anaerobic (low oxygen or ‘reducing’) environments and are present along much of the NSW coast and within inland river or swamp systems. ASS can become disturbed during excavation and broad-scale drainage works or as a result of groundwater dewatering. These activities expose the sulfide minerals to air, which cause oxidation of the sulphide minerals, leading to the formation of sulfuric acid. ASS occur all around the country and if left unmanaged the sulfide oxidation process can make the groundwater acidic, causing naturally-occurring heavy metals (such as iron, aluminium, arsenic and copper), to be leached from the soil and transported to surface water bodies. This can lead to adverse impacts on vegetation, aquatic organisms (including ‘fish kills’), as well as causing damage to steel and concrete structures (corrosion) such as pipes, culverts, bridge piers or retaining walls.
NR Engineering Consultants provides the following acid sulfate soils services:
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Field assessment of potential and actual acid sulfate soils (PASS and AASS);
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Advice on the handling, treatment and disposal of acid sulfate spoil (excavated ASS materials);
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Assessment and management of water quality impacts;
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Management of areas affected by acid sulfate soils, including remediation of impacted sites; and
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Development of Acid Sulfate Soil Management Plan (ASSMP).
