5.0 Toxicology Quiz (Case Study)

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Lead exposure and aggressive crime in Australia?

According to the Mineral Commodity Summaries (2015), Australia is one of the world’s largest producers of lead. Sources of lead exposure in Australia include lead paint, lead petrol, lead mining and smelting. Kristensen (2015) estimated emissions from lead petrol use in Australia from 1932 to 2002 to be greater than 240 kilotonnes. The following figure from the paper shows that the phasing out of organolead use in gasoline and fuels has resulted in a dramatic decrease in atmospheric lead emissions in Australia:

There are many lead remediation activities occurring around the world. An important local cause of high childhood lead exposure in Australia has been the emissions from the Cockle Creek lead smelter located in Boolaroo (near Newcastle), New South Wales (NSW). During the operation of the Cockle Creek lead smelter from 1896 to 2003, children’s mean blood lead levels were measured at more than three times the current Australian intervention level of 5 µg/dL. A Lead Expert Working Group (LEWG) was established by the NSW Environment Protection Authority (EPA) Chair and Chief Executive Officer, Barry Buffier, in December 2014. The group was established to evaluate the effectiveness of the Lead Abatement Strategy (LAS). A report on managing residual lead contamination around Boolaroo and North Lake Macquarie is available here.

In 2014 Dominic Casciani, BBC home affairs correspondent asked the question: Did removing lead from petrol spark a decline in crime? He states:

“For most of the 20th Century crime rose and rose and rose… Then, about 20 years ago, the trend reversed – and all the broad measures of key crimes have been falling ever since. Offending has fallen in nations whose governments have implemented completely different policies to their neighbours. If your nation locks up more criminals than the average, crime has fallen. If it locks up fewer… crime has fallen. Nobody seems to know for sure why. But there are some people that believe the removal of lead from petrol was a key factor.”

As pointed out by Stretesky and Lynch (2004), the relationship between lead and criminal behaviour is not straightforward. In terms of causation, crime is a multifactorial problem. Thus the question becomes what is the effect of lead exposure on the risk of criminal behaviour over time and geographic space and how much additional risk does lead exposure pose in terms of the background risk of crime? Is lead exposure an important covariate of crime in Australia? Would reducing lead exposure in Australia reduce violent crime rates?