acid sulphate soil investigation

Acid Sulfate Soil Investigation and Management Plan, Mornington Peninsula VIC

acid sulphate soil investigationAn industrial development in Hastings was planned in an area of acid sulfate soil occurrence which required vigilance and attentive management. Acid sulfate soils are naturally occurring along Victoria’s coastal zone and if left undisturbed, are generally non-threatening. However, when exposed to air, acid sulfate soils produce sulfuric acid and soluble iron which can be detrimental to natural and built environments as well as mobilising additional pollutants within the soil. Other environmental impacts include acidification of water and soil, de-oxygenation of water, poor water quality, dissolution of soil, rock and concrete, corrosion of metals and in more extreme circumstances, fish kills.

In Victoria, the Industrial Waste Management Policy 1999 (Waste Acid Sulfate Soils) requires that waste acid sulfate soils sourced from the premises be managed onsite according to the latest best practices to ensure prevention of adverse impacts on all beneficial uses of any element of the environment on and offsite. The Department of Sustainability and Environment developed the Victorian Best Practice Guidelines for Assessing and Managing Coastal Acid Sulfate Soils (BPMG) in 2010 to guide landowners, developers, planners and decision makers through a risk identification approach that will assist them to make decisions about the assessment and management of coastal acid sulfate soils.

iEnvi was engaged to assist the client investigate areas of potential acid sulfate soils (PASS) and create an acid sulfate soil management plan (ASSMP). Close to 50 samples were collected from 24 soil bores at different depths to identify the soil horizons of which potential acid sulfate soils (PASS) could be present during the development. pHF and pHFOX field tests which are a measure of pH before and after oxidation of soils were undertaken for all samples before delivered to the laboratory for further analysis (SPOCAS). From the investigation, the presence of PASS was mapped and an ASSMP was developed accordingly. Currently, iEnvi is executing the ASSMP which involves soil testing and water quality monitoring during construction development to safely manage acid sulfate soils.

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