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Reducing the harms of toxic air in mining and smelting communities

Mount Isa exceeded the national one-hour standard for sulfur dioxide emissions 49 times in 2012. Zurbagan/Shutterstock

Children in the mining towns of Mount Isa in Queensland and Port Pirie in South Australia are exposed to harmful levels of pollutants that increase their risk of learning and developmental disorders, and a number of serious illnesses.

A study we published today in the journal Aeolian Research shows mines and smelters in these two towns have avoided any serious scrutiny over their atmospheric emissions of arsenic, cadmium (a heavy metal used in the manufacture of batteries), and sulfur dioxide.

Along with lead, these toxic substances are emitted at much higher levels than anywhere else in Australia. Port Pirie exceeded the national one-hour standard for sulfur dioxide emissions 50 times in 2012. And recent 24-hour levels for lead, arsenic and cadmium were 45-times above recommended annual air quality levels for lead, 42-times above recommended levels for arsenic and 36-times above for cadmium.

Mount Isa also exceeded the national one-hour standard for sulfur dioxide emissions 49 times in 2012. And recent 24-hour maximums were 25-times above recommended annual levels for lead, 495-times higher for arsenic and 36-times higher for cadmium.

The licencing, regulation and reporting of toxic air pollutants and related health effects in Mount Isa and Port Pirie is inconsistent, incomplete and misleading. It’s time for effective regulation to protect the health of local residents.

Health harms

So, what impact are these emissions having on the local communities?


Arsenic emissions from smelters are highly toxic; there are no safe levels of exposure. Although the effects of arsenic can take years to emerge, exposure is associated with skin lesions, damage to the peripheral nerves, gastrointestinal symptoms, diabetes, kidney disease, heart disease and cancer.

A study of children living around a Mexican smelter also showed arsenic exposure affected children’s cognitive development.


Cadmium emitted from the mining and smelting operations can have harmful effects on the kidneys, the skeletal system and the respiratory system, and is a known cause of cancer. Even at low levels cadmium has also been associated with learning difficulties in children.

Sulfur dioxide

Elevated sulfur dioxide emissions are associated with increased problematic respiratory symptoms, disease and mortality as well as hospital admissions for asthma.

The most recent data for Mount Isa shows that between 2002 and 2006 there were significant disparities in asthma rates for Mount Isa compared to the rest of Queensland. Hospitalisation rates are significantly higher (80%) compared to the rest of Queensland, and asthma mortality rates were 322% higher than the rest of the state.

Hospital admissions for respiratory illness are similarly high in Port Pirie. In 2007-08 there were 3,774 admissions per 100,000 people, compared with 2,036 per 100,000 for the remainder of South Australia.


The effects of lead exposure are greatest in unborn children and those aged under five years. This age group is most susceptible because their growing nervous and skeletal systems require high levels of calcium.

Calcium is an essential element for the proper development and function of the brain. Because lead (Pb2+) mimics calcium (Ca2+), children living in a lead-rich environment absorb larger amounts of lead in place of calcium. This can interfere with the critical development of a child’s nervous system.

Children in Mount Isa and Port Pirie face air pollution levels that would not be acceptable elsewhere in the country. Nadina/Shutterstock

Australian guidelines recommend Australian children have blood lead levels less than ten micrograms per decilitre (10 µg/dL), though this is currently being reviewed and should be lowered to a minimum of five micrograms per decilitre, but preferably lower.

At Port Pirie in 2011, 24.2% of children under five years had blood lead values above ten micrograms per decilitre. The proportion was similar in 2012, at 24.9% and slightly lower in 2013, at 22.7% At Mount Isa, a 2008 study of 400 children aged one to five years revealed 11.3% had a blood lead level above ten micrograms per decilitre.

A smaller survey of 167 children in 2010 showed the impacted was lower, at 4.8%, but with another 4.2% recording a blood lead level of nine micrograms per decilitre.

Misleading reporting

Our study discovered two critical ways in which the public are misled about the nature and extent of pollution.

First, is the selection of more favourable figures for blood lead values reported in children.

At Port Pirie, it is common practice for the South Australian health department to use the data including maternal surrogate blood values: the mother’s blood lead values. These are used in the absence of values for a child under nine months months of age. While these may correlate to new born’s levels, they are not children’s results and, in any case, blood lead values rise rapidly after around two months.

In addition, unlike protocols used for Broken Hill children’s blood lead assessments, only the last blood lead measure on a child in any year is used, irrespective of whether there are higher values from earlier in the year.

Together, the data from 2006 to 2010 shows this downplays the percentage of children who actually present with a blood lead value over ten micrograms per decilitre by 5.8% and 13.6%.

Second, at Mount Isa, the Queensland government is failing to use Australian or Queensland statutory air quality values to calculate the local air quality index for lead and arsenic. The statutory values for lead and arsenic are based on yearly averages and are set a maximum of 0.5 and 0.006 micrograms per cubic metre of air, respectively.

However, the government online air quality system uses higher 24-hour concentration values for lead and arsenic of 2.0 and 0.3 micrograms per cubic metre of air, respectively, to present a more favourable picture of emissions. Indeed, in the explanation of the calculation of the air quality index the government maintains it uses the lower Australian or Queensland statutory values.

On a sample day in December 2011, for instance, the concentrations of lead-in-air of 0.784 micrograms per cubic metre of air were published as being “good”, while arsenic-in-air were recorded as “fair”, at a concentration 202 micrograms per cubic metre of air.

But proper calculation of the index values, show they would be both poor with an index of 156.8 and 3,366 for lead and arsenic. So this means the levels are 56.8 and 3,266 percentage points above the recommended pollution goal.

Reducing the harm

Eight years ago Mount Isa Mines promised the community a Lead Pathways Study that would include the most critical aspect – air quality data. They are still waiting.

In the meantime, we already have overwhelming evidence that the communities of Mount Isa and Port Pirie are being unfairly and unreasonably subject to air pollution levels that would not be acceptable elsewhere in the country.

To achieve the objectives of the relevant state environment protection legislation and not compromise ecological sustainability and the health of the local communities, we need more frequent sampling, higher standards and shorter averaging periods for air quality.

We also need enforceable legal mechanisms that enable the environmental protection agencies (EPAs) to not only regulate more effectively but to actually stop ongoing systematic pollution by forcing closure, even if only temporarily.

This must be accompanied by a willingness within the EPAs to take such action, independent of manipulation by government or industry, as appears to be the case at present.

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