A study into lead has raised new concerns about how much exposure is safe and suggests harm occurs even at low levels.

The American study published in Lancet Public Health, argues that any level of lead is unsafe because even at low levels it can have toxic effects on multiple organ systems.

A spokeswoman from Mount Isa Mines said it would be “inappropriate” to comment on the study as they are not a health authority. 

While there is no level considered safe, a blood lead level more than five micrograms per decilitre is used as an indicator to determine unusual exposure.

Previous estimates assumed that low level exposure did not increase the risk of premature death.

The study’s lead author Professor Bruce Lanphear said there is an increased risk of death at levels between 1 and 5 micrograms per decilitre.

“Still, lead represents a leading cause of disease and death, and it is important to continue our efforts to reduce environmental lead exposure,” Professor Lanphear said. 

Queensland Chief Health Officer Jeannette Young said Mount Isa was still a safe place to live. 

“We encourage all Mount Isa residents to be tested regularly and to have their children tested,” Dr Young said.

“While these impacts cannot be entirely removed, various steps can and have been taken to mitigate and minimise them.”

She said the health department supports the mandatory notification level of five. 

Australia’s National Health and Medical Research Council said there were no plans to revise the mandatory blood lead level.

Traegar MP Robbie Katter said he was supportive of getting key messages out to those people who may be exposed to any levels of lead in the community. 

“In Mount Isa we have been very successful in keeping blood lead levels down by communicating consistent messaging on how to minimise the impact of lead in our soil on blood lead levels, raising community awareness and working with stakeholders,” Mr Katter said. 

“But we also need to remember not to unduly alarm people.

“There is no good level of lead exposure but the higher it is the more risk there is– so it is very important to minimise the levels  as effectively as possible.’’

The Lancet study has already garnered support from academics around Australia. 

Senior University of Adelaide medical lecturer Dr Ian Musgrave said lead is a well known persistent environmental toxin.

“While most Australians would be aware of chronic exposure to lead's effects on brain development and behaviour in children, fewer will be aware that long-term exposure to relatively low levels of lead increases blood pressure and the risk of heart and blood vessel disease,” Dr Musgrave said. 

The data from the study is a cause for concern, says Associate Professor of Biophysics at the University of South Australia Ivan Kempson.

“Many toxic effects of lead have been known for decades but it is only with studies, such as this, of increasing rigour, that the longer term effects and more subtle effects are being identified,” he said. 

“This latest study drives home the long term impact that lead exposure, even below previously accepted levels, has significant impact on public health.” he said. 

“This new insight into the impact of low lead level exposure should direct more efforts into the remediation of polluted sites around Australia and reduce our current definition of what is considered safe. "

Macquarie University’s Professor Mark Patrick Taylor said there is no reason to believe Mount Isa is immune to the consequences of lead exposure as detailed in the new study.

“This new study confirms earlier, emerging views that lead is a significant contributor to heart disease in exposed populations,” Professor Taylor said.

“Other recent research has confirmed that previously elevated lead-in-air exposures were associated detrimental outcomes and anti-social behaviors, including increased rates of aggressive crime and death by assault.

He said people living in Mount Isa are “still subject to significant environmental injustices due to the massive lead exposures they continue to be subjected to”.

“Mount Isa lead in air levels remains elevated at approximately 20 times those in Sydney.” Professor Taylor said. 

He said it was not surprising that half of the children living in Mount Isa have blood lead levels above the safe level of five micrograms per decilitre.

Professor Taylor said Indigenous children in Mount Isa are worse off, with as many as 70 per cent having levels above the upper limit. 

“The Australian public should be incredulous that we have permitted such blatant injustices to be imposed upon sensitive populations (children), for which the effects will not fully bear fruit until their later years.”

The Lancet study assessed lead levels in more than 14,000 people over a 20 year period.

The results showed exposure at low levels was a leading risk factor for premature death in the USA, potentially accountable for one in three cariovascular deaths.