Scientists tackle acid menace

Australia's clean-up scientists are getting ready to kick ASS (otherwise known as acid sulphate soils).

Researchers from CRC for Contamination Assessment and Remediation of the Environment (CRC CARE) and the Queensland Department of Natural Resources and Water (QDNRW) are teaming up to take on the $10 billion ASS menace that is threatening estuaries, coastal development, water supplies and urban infrastructure round the nation.

The team is led by Dr Richard Bush from Southern Cross University's Centre for Acid Sulfate Soil Research and will develop new risk-based methods to control the release of acid from a highly degraded wetland at East Trinity near Cairns, Queensland.

They will establish a $2.75 million national demonstration site to test new acid management techniques that can be used wherever the problem occurs in Australia, says the managing director of CRC CARE, Professor Ravi Naidu.

"East Trinity is also likely to become a site of international significance in developing new ways to curb the acid sulphate soils menace," adds the CRC's Professor Leigh Sullivan. "ASS problems occur elsewhere in the world and we need to develop satisfactory solutions and Australia is pioneering these."

The problem occurs when soils rich in natural metal sulphides are drained, exposed to the air (oxidized) and then re-flooded, which,causes them to release sulphuric acid. The acid discharges are lethal to fish, water plants and other organisms, leading to rivers and estuaries which are often crystal clear, but dead. They can also hit human health, eat concrete in buildings and pipes, cause a catastrophic decline in water quality and sterilise soils.

Awareness of this process has halted an estimated $10 billion's worth of development in sensitive coastal areas around Australia.

The new risk assessment and remediation tools developed by the team will convert low-value acid-affected sites with high environmental risk to high-value development sites that have a low environmental risk.

Scientists from Queensland's DNRW have been treating the East Trinity site since 2000 and have already succeeded in substantially reducing the acid and metal discharges that were causing environmental problems.

East Trinity's proximity to the Great Barrier Reef World Heritage Area makes it a site of particular local and international concern. Other high-profile sites affected by ASS include the Olympic site of Homebush Bay in Sydney, Telstra Dome in Melbourne, Adelaide's Gillman site and the Gnangarra Mound which supplies part of Perth's drinking water.

When remediation is finished the East Trinity site will become a valuable eco tourism destination, Professor Sullivan predicts.