WATER quality around the QAL refinery has been called into question by the state's environmental watchdog.

The most worrying statements in a Department of Environment and Heritage Protection report discuss the possibility water quality near QAL could be a threat to fish health.

DEHP has found dissolved metals aluminium and molybdenum exceeded trigger levels at South Trees Inlet in Gladstone Harbour, the area around QAL.

It also says the dissolved metals could be linked to the red mud dam at the refinery.

The report found water quality in Gladstone Harbour posed no threat to fish health, "with the possible exception of sites around South Trees Inlet."

The report is one of the monthly reviews of Gladstone Harbour in response to public concern over the major dredging project.

>> Read the report here

Throughout the entire harbour, testing found only five sites with aluminium levels above the trigger value - all five were in the South Trees Inlet area.

South Trees Inlet is not near the dredging project.

DEHP deputy director general Dean Ellwood yesterday said the department was investigating and had asked QAL to conduct further toxicity and chemical tests.

The results of those tests are expected next year.

"DEHP has requested Queensland Alumina Limited to carry out tests on waters being discharged from its red mud dam and the waters of South Trees Inlet to determine if they are safe for aquatic species," Mr Ellwood said.

Gladstone Conservation Council president Jan Arens said dredging could not be ruled out as part of the cause of high aluminium levels in Gladstone Harbour.

The DEHP report found dissolved aluminium levels above trigger levels at five sites near QAL, rather than sites near the dredging project, but Mr Arens said that did not put dredging in the clear.

"The fact that we are now seeing that it may well be coming from South Trees Inlet and may be a function of the discharge from the red mud dam tells you that perhaps we are looking at a combination of problems."

QAL declined to comment for this story.

>> Read the department's response to our questions here

Main points:

  • The final paragraph of the report's conclusion shows how seriously DEHP is taking the findings: "Investigations of the South Trees Inlet sites and the influence of the red mud dam on the concentration of dissolved metals should continue in future monitoring. Given that dissolved aluminium concentrations are persistently elevated, the forms of dissolved aluminium and their toxicity warrant further examination. Based on the available data it is unlikely that metals are causing any ongoing suppression of the immune system or increased susceptibility to disease throughout Gladstone Harbour and its associated waterways with the possible exception of South Trees Inlet."
  • The report found no harmful impact on water quality from the dredging project
  • The red mud dam at QAL contains a red sludge that is a by-product from processing bauxite into alumina. It contains elements such as molybdenum, vanadium, gallium and aluminium.
  • The aluminium low reliability trigger value is 0.5 ug/L. Sites at South Trees inlet had readings ranging from 14 to 38 ug/L.
  • Molybdenum was also above the trigger value at two sites in South Trees Inlet with concentrations of 25.3 μg/L and 28 μg/L. Molybdenum is a byproduct from the processing of alumina at QAL
  • The report finds the aluminium concentrations are unlikely to be a result of dredging. However, it makes a direct link with QAL's red mud dam: "There are a number of potential sources of aluminium in Gladstone waterways, principally natural tidal induced re-suspension of sediments and operations associated with aluminium related industries including Queensland Alumina Limited (QAL), Boyne Smelters and Rio Tinto Alcan Yarwun. Aluminium is a fingerprint identifier of most alumina refineries. The elevated aluminium concentrations in South Trees Inlet have been attributed to the red mud dam discharge from the alumina refining process. This is the most likely reason for the exceedances of the low reliability aluminium trigger value at South Trees Inlet sites since the start of the Queensland Government monitoring in February 2012."