How dirty is the bottom of Sydney Harbour?

We know the condition of the water in Sydney Harbour and other estuaries, bays and rivers. What about the mud at the bottom? Until now, there have not been consistent ways to measure these sediments which are essential to aquatic life.

Research by a team from CSIRO's Centre for Environmental Contaminants Research, led by Dr Graeme Batley, has developed the tools to provide the answer. And their reward is the $10,000 Land & Water Australia Eureka Prize for Water Research.

Aquatic sediments are important food sources and breeding grounds for aquatic animals " yet the same sediments are where most water-borne contaminants end up.

Prior to 2002, there were no standard guidelines on how to measure the environmental impact of contaminated sediments in Australia, under local conditions.

The Sydney-based CSIRO team took the lead in developing guidelines. Yet, when these guidelines were published in 2002, there was a new hurdle " no appropriate bioassays and no consistent standards on how to collect and handle samples.

The team found a host of problems with the traditional methodologies that were in use around the world. For example, sediments are unstable and so the act of sampling could change the result. Also, small changes in the preparation of samples could lead to wildly exaggerated results.

They also found that in some cases the toxicity of metal contaminants was being overstated. Conversely, they found that in other sediments the potential for contaminants to enter the food chain was understated.

Four years later and the team has created a wide range of reliable assays and procedures.

Their "Handbook of Sediment Quality Assessment' has turned out to be a bestseller " with over 15,000 downloads from their website. And their work is being used not only in Sydney Harbour to assess the impact of remediated Harbourside industrial sites, but also at ports and mines around the country.

The Land & Water Eureka Prize for Water Research is awarded to an Australian individual, team or organisation for highly innovative research that has made, or has the potential to make, an outstanding contribution to the protection, sustainable use and management of Australia's water resources and water-dependent ecosystems.