Australasian Science: Australia's authority on science since 1938

The Miner’s Myth

By Mark Patrick Taylor & Louise Kristensen

Several myths have been propagated to counter compelling evidence for community health issues arising from mining and smelting operations in Mount Isa and Broken Hill.

Ore extraction and processing results in elevated levels of toxic metals around lead mining and smelting operations, causing adverse health effects, particularly in children. Despite this, resource companies and government agencies have constructed “myths” that downplay potential exposure risks as well as any responsibility arising from them. The issuing of statements such as the following are commonplace: contaminants are naturally occurring, the wind blows emissions away from residential areas, contaminants are not bioavailable, contamination is a legacy issue, or children have been exposed to lead from paint, petrol, or from eating fishing sinkers.

When independent research challenges such arguments, the typical modus operandi is to attack the messenger – that is, the scientist. Our studies of the sources, causes and human health risks of environmental pollution have been subjected to several such non-factual distracting criticisms, including: “Mr Taylor is a left-wing greenie trying to shut down mining”; “the researcher must work in hospital-like conditions”; “this gentleman has a history of writing such reports”; and “the smelter is contributing $1.6 billion into the state economy – what is Professor Mark Taylor contributing?”

The “miner’s myth” that environmental contamination in mining and smelting towns is naturally occurring can be a difficult scientific hypothesis to test. Furthermore, the widespread use of the phrase “naturally occurring” causes confusion and delays remediation work, hindering efforts to reduce harmful exposures to the most vulnerable population – children. When the status quo is challenged with sound data published in peer-reviewed journals (the gold standard for research), it’s not atypical for both government officials and industry employees to rebut any such claims in the following ways: mining and smelting emissions operate within mandated licence limits; the facility meets best practice in terms of environmental management and monitoring; and emissions do not occur at levels that are harmful.

While the first two of these arguments may be factually correct, the salient and more difficult issue is the third point. Significant investment is required to establish a causal link to human or environmental harm.

Specifically, the issue of establishing a causal link between operations and human exposures has stymied clean-up programs in Broken Hill and Mount Isa, where major lead–zinc–silver ore bodies have been mined continuously for more than 130 years and 90 years, respectively. The consequence of the mining and smelting has been a long history of elevated blood lead exposures in occupational workers as well as local residents. The most recent comprehensive blood lead studies reveals that approximately 50% of children under 5 years of age exceed the Australian blood lead intervention value of 5 µg/dL. These children are at risk of life-long cognitive damage, including lower IQ scores.

Notwithstanding this, there has been a long history of constructed truths about the sources and harms associated with ore processing operations in these cities. In tackling this problem at Broken Hill and Mount Isa, we have applied a geoforensic approach to compiling robust, multiple lines of evidence to establish the most likely cause of lead exposure. The goal of our research has been to stimulate the implementation of more effective environmental standards and clean-up.

Our peer-reviewed research has required us to collect and analyse hundreds of air, dust, soil and sediment samples for their metal content. We have also examined the lead isotopic composition of samples, and found that contemporary contamination is coming from the ore body. Moreover, analysis of surface soils, aerosols and fresh dust deposits reveals higher concentrations closer to the operations, consisting of particles that can only have been formed by recent ore processing. We have bootstrapped our findings to geological data, historical environmental assessments and old photographic evidence to establish the preponderance of evidence concerning the source and cause of contamination.

The compilation of robust evidence is critical in shifting the debate and the actions of government and industry. In 2015 the NSW government invested $13 million to establish the Broken Hill Environmental Lead Program, which aims to ensure that children aged 1–4 years will have a blood lead level of no more than 5 μg/dL. Specifically, the program will have an emphasis on Aboriginal children who have higher incidences of elevated blood lead levels.

At Mount Isa, the Queensland government introduced new and partially improved environmental requirements for the mining and smelting operations in 2012. By the end of 2016 Mount Isa Mines will also have completed works and investments to improve environmental performance at their site. These investments include new emission capture technology and ore management techniques totalling more than $600 million.

While there have not been any overt industry admissions about the sources and human health consequences of lead emissions, the mining operators’ licence to pollute is being addressed. It’s anticipated that, in time, all children will have blood lead levels that are below the national intervention value.

Needless to say, we will be watching – carefully.

Mark Patrick Taylor is Professor of Environmental Science at Macquarie University, where Louise Kristensen completed her PhD in 2016. She is now a postdoctoral researcher at the University of California, San Diego.