A second phase of research in Port Curtis recently conducted by the Coastal Cooperative Research Centre has determined that the harbour still remains relatively healthy.

A recent presentation of results to industry, managers and stakeholders by the combined team from CSIRO and CQU indicated positive findings on the health of local waterways.

Extensive surveys of the port included measuring contaminants in water, sediments and marine organisms and examining the health effects of these contaminants on marine life.

Although concentrations of some dissolved metals were elevated in harbour water, they were not above levels of regulatory concern and returned to natural background levels in coastal waters. Metal concentrations were higher in The Narrows and this may be associated with natural inputs from mangrove areas.

A new hydrodynamic model being tested in the harbour determined that water flushing times are probably longer than previously thought; around 19 – 24 days. Metal concentrations were high in a range of plants and animals living within the port compared to those from a coastal reference area and this may be due to the high retention time of water (and therefore available contaminants) in the harbour.

New tools were used to assess the health of organisms exposed to contaminants in the harbour. These included the use of biochemical markers such as stress enzymes in oysters and imposex (growth of male genitalia in females) in snails. In addition, laboratory studies explored the different responses of organisms to periodic or continuous exposure to discharged contaminants.

Sediments were found to contain much lower levels of naphthalene (a potentially harmful PAH) than previously thought. PAHs are derived from a number of sources including oil shale and coal, but levels across the harbour were well below guidelines. Sediment cores also indicated that there have been no major contaminant inputs in recent history.

The pathway of contaminants up through the aquatic food chain was determined to be complex and scientists are still unravelling the story.

For details contact:.

Maria Vandergragt.

Projects Manager.

Port Curtis and South-east Queensland.

Coastal CRC.

Phone: 07 4970 7289 or 07 38969528 .

Website: http://www.coastal.crc.org.au/