Mercury left out of fish tests
THE Queensland Government did not test for mercury during toxicology tests done on barramundi from Gladstone Harbour last year, despite concerns about mercury contamination in fish in the area being raised 10 years ago.
The tests have come under scrutiny in the past week since the Gladstone Fish Health Scientific Advisory Committee released its final report, which revealed the panel was unable to come to a definitive conclusion on what has caused fish diseases in the harbour area.
While the summer flooding a year ago was identified as the cause of some marine animal deaths in the area, speculation remains rife in Gladstone's commercial fishing industry about whether a dredging project by the Gladstone Ports Corporation contributed to fish diseases, a point which port management denies.
In toxicology test results released in December last year, Queensland Health's forensic laboratory tested three barramundi samples for heavy metals including aluminium, arsenic, barium, cadmium, chromium, nickel, copper, iron, zinc, silver and selenium.
Biosecurity Queensland, which ordered the testing, did not ask for mercury or lead levels in the fish samples to be tested, on the grounds that the environmental impact assessment completed before the Western Basin Dredging program began found that mercury and lead were "not of concern".
But a doctoral report published by Central Queensland University (CQU) in 2002 found that mercury levels in barramundi were a concern, due to bio-accumulation of the heavy metal by predator fish in the area.
An addendum to the Western Basin Dredging and Disposal Project Environmental Impact Statement also said that chemical analyses done on sediment in a potential dredging area found that levels of mercury, arsenic, copper, lead and nickel were exceeding the Federal Government's National Assessment Guidelines for Dredging.
This report did, however, state that the levels of mercury may have been naturally occurring.
The CQU report also said the effects of mercury on fish could include necrosis (cell death) in internal organs and tissue.
Previous government tests found a high number of fish samples with tissue necrosis, among other symptoms, as well as a flatworm that affected fish health.
Fisheries Queensland did not respond to questions yesterday.