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© The Australian
Childhood exposure to environmental lead has been linked to mental, behavioural and physical deficits, and now the toxic lead dust has been connected to violent assault.

According to US researchers who compared statistics for six cities: Chicago, Indianapolis, Minneapolis, San Diego, Atlanta and New Orleans, rising levels of airborne lead dust lead to spikes in the rates of aggravated assault as exposed children grew up.

The findings, reported today in the journal Environment International, have implications for Australian mining communities, claims Mark Taylor, an environmental scientist at Macquarie University.

"There is an ongoing problem of environmental lead exposure from legacy mining and smelting, as well as contemporary production processes, especially in Port Pirie and Mt Isa," Professor Taylor said.

The new data comes from Howard Mielke, a specialist in environment and health with Tulane University in New Orleans, Louisiana, and epidemiologist Sammy Zahran, co-director of the Centre for Disaster and Risk Analysis at Colorado State University.

They point to a growing body of scientific evidence that childhood exposure to lead dust causes permanent damage to regions of the brain that govern mood regulation, executive control and judgment.

Professors Mielke and Zahrran found 90 per cent of the variation in aggravated assault across the US cities was explained by the amount of lead dust.

After controlling for other possible causes such as community and household income, education, policing effort, and incarceration rates, they found every 1 per cent increase in tonnage of environmental lead released 22 years earlier, raised the present rate of aggravated assault by 0.46 per cent.

National Australian data has not been collected, but statistics are telling.

According to Queensland Police Service statistics for 2006-2007, there were 2189 aggravated assaults per 100,000 of population in the mining and smelting town of Mt Isa, the highest in the state. In contrast, in Gladstone, where Australia's largest aluminium smelter operates, the figure was 427 per 100,000.

Mt Isa's assaults cannot be attributed to drunkenness as alcohol offences were nearly half that of Brisbane, with the second highest assault rate.

Likewise, in 2010 Broken Hill had 893.1 non-domestic violence related assaults per 100,000 of population. The rate for NSW was 550.8 and for Sydney, 488.4.

The drop in assaults in the US mirrors moves to phase out lead in petrol beginning in 1972 and ending with a nationwide ban in 1984. Australia phased out leaded petrol nationally on January 1, 2002.