QAL'S red mud can be used to neutralise heavy metals and acids at mine sites.
QAL'S red mud can be used to neutralise heavy metals and acids at mine sites.

Fears over metal levels in South Trees Inlet

DISSOLVED aluminium levels in South Trees Inlet, near the QAL red mud dam, rose sharply in September.

Data collected in August showed a maximum dissolved aluminium level of 38 ug/L. That level prompted the Department of Environment and Heritage Protection to raise concerns in a report.

However, the September data showed dissolved aluminium levels in the inlet had risen to a maximum of 208 ug/L.

There is no doubt the aluminium levels are connected to QAL's red mud dam.

That is not a matter of controversy.

The question being asked by DEHP is: Are those aluminium levels safe for marine life?

To the untrained eye, readings of 131-208 ug/L at various points of South Trees Inlet look extremely high, especially considering the rest of Gladstone Harbour had levels which were too low to be detected.

However, there is no solid evidence to suggest the levels pose a threat to fish health.

QAL remains confident dissolved aluminium levels in South Trees Inlet are safe for aquatic life.

"During QAL's 40 years of operation, QAL has conducted multiple scientific studies into the potential impact of discharge from QAL's residual disposal area on the receiving environment," a QAL spokesperson said. "These studies have all found the discharge has had negligible impact on the marine environment and marine species.

"The latest study was completed in 2011 and included assessment of toxicity on key indicator species, such as barramundi and oysters.

"Aluminium levels from these studies, as well as ongoing monitoring, show levels within the range reported by the DEHP. Studies have shown these levels do not pose an impact to the environment."

DEHP is giving little away in terms of its own concerns.

DEHP deputy director-general Dean Ellwood said QAL was cooperating with the department.

"With consistent elevated levels of some metals in South Trees Inlet during 2012, the Department of Environment and Heritage Protection has requested QAL to carry out additional 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.

Aluminium levels for October

ALUMINIUM levels in South Trees Inlet for the month of October will not be released until next year.

Monthly readings were taken during a 12-month program ending in September.

That program was to address community concerns about the Western Basin Dredging project, but it showed dissolved aluminium levels around QAL's red mud dam rising to by far their highest level in September.

Because the program has come to an end, there is no data to show what those levels did during October.

DEHP executive director Reuben Carlos said QAL would conduct a new monitoring program.

"The program will include monitoring of dissolved metals and conducting toxicity tests at three-month intervals commencing this summer," Mr Carlos said.

"Results of the tests are expected to be available next year."