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Acid Sulphate Soils and Seawater

3 January 2010

At the 18th NSW Coastal Conference in November 2009 a paper was submitted titled, "Remediation of coastal acid sulfate soils by tidal inundation: Effectiveness and geochemical implications".  This paper was presented by scientists from the Centre for Acid Sulfate Soil Research, Southern Cross GeoScience, Southern Cross University, NSW.

An excerpt from the abstract of this paper says; 
"The effects of restoring marine tidal inundation to a severely degraded acid sulfate soil landscape were investigated. Five years of regular tidal inundation led to substantial improvements in a range of key parameters used to assess soil and water quality. The pH of estuarine creeks improved dramatically following reintroduction of tidal inundation."  

The abstract continues; 
"This study demonstrates that marine tidal inundation can be an effective method for remediating acid sulfate soils at a landscape-scale. However, there are a range of potential geochemical complexities which need to be considered prior to implementing this technique."

The paper goes on to say; 
"Tidal inundation of ASS is a potentially lowcost, landscape-scale remediation technique which has recently been trialled in far north Queensland. It is well suited to situations where the site is close to a large marine source, where the elevation of ASS is close to mean sea level and conventional agricultural landuse has been abandoned."

Loveday Bay, SA- 200 ha of acidic water as of August 2009

Loveday Bay (200 ha) has already turned acidic. Lake Albert's clayey centre is also at high risk of turning acidic as it dries out this summer.

What is very clear from this report is that the longer we wait, the more difficult and lengthy the remediation becomes, even with seawater.

And while we wait, Loveday Bay is still there festering away generating more acid day by day with no public plan in sight for remediation.  But if you think Loveday Bay is bad, wait until the rest of Lake Alexandrina and Lake Albert turn acidic.