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Author: Mark Taylor, Chris Winder and Bruce Lanphear
Source: ABC
Date: 15 October, 2013

THERE IS NO SAFE LEVEL of exposure to lead for our children. This is a significant problem for children living in contaminated areas, because children breathe in air and ingest dirt that contains tiny amounts of lead. And while the rest of the world has been responding to the need to lower and effectively eliminate lead from the environment, health advisors to the Australian government have prevaricated over the evidence to support these reductions.

Lead exposure in Australian communities is dominated by three sources: mining and smelting emissions; lead paint; and leaded petrol. Lead levels in paint were up to 50 per cent by weight before the 1950s but thereafter several reductions were mandated bringing the allowable concentration to 0.1 per cent in 1997.

Unleaded petrol was introduced in Australia in 1985, with the lead content in petrol declining from 0.84 g/L in 1990 to 0.2 g/L in 1996, until it was finally banned in 2002.

But as a result of the lead-heavy bad old days, many of the older, inner city areas of Australia became heavily contaminated with lead. It is this historical lead that children continue to be exposed to.

And although Australia continues to be a world leader in lead metal mining, smelting and processing there has been a significant lack of research funding directed towards understanding exposures and the real risks associated with the lead industry.

For example, there has never been any major long-term study investigating environmental lead plus other metals exposures in the lead-mining towns of Mount Isa or Broken Hill. Rachel Earl did a study in 2011 on Port Pirie and Broken Hill as part of her PhD and her study (pdf) drew the same conclusions as previous international studies: that there was no safe, lower threshold for lead exposure and that low and initial lead exposures may indeed cause proportionately greater impact on children’s cognition than higher levels.

However any negative human health impact arising from lead extraction and refining has been down-played consistently by mining companies, governments, councils, health officials and regulators so as to not challenge the status quo and disrupt economic opportunities for remote rural Australian towns and the wider Australian community.

As a consequence, affected Australian communities have never been able to assess the real risk to their health. Meanwhile, communities residing adjacent to lead mining, smelting and refining centres such as those in Broken Hill, Port Pirie and Mount Isa continue to be exposed to environmental lead and continue to be protected inadequately by out-dated standards.

The quiet concern about lead exposure is very clearly evident in Medicare statistics that show 107,810 blood lead tests were conducted on all Australians in the last decade. It is a significant lost opportunity that the results from these tests are not captured and analysed by the NHMRC as part its work the work to raise the standard of individual and public health throughout Australia.

Science shows that lead exposure is associated with a delay in the start of puberty and adverse reproductive and development effects in young adults who have mean blood levels less than or equal to 5 millionths of a gram per 100 millilitres of blood (or micrograms per deciliter: μg/dL).

Adults are not protected from exposures either. The US EPA concluded in 2013 that causal relationships exist between low-lead exposures (less than 10 µg/dL) and damage such heart disease and hypertension. They also concluded that lead exposure is likely to contribute to reduced kidney function. In addition, there is strong evidence also that lead exposure reduces semen quality and may affect some aspects of female reproductive function.

In about 1960, health agencies in Europe and the USA set a blood lead “level of concern” at 60 μg/dL. Then, as more evidence became available it was lowered to 40 μg/dL in 1971; to 30 μg/dL in 1985; and lastly, to 10 μg/dL in 1991. This was the level that pediatricians and other health professionals could use for establishing priorities and interventions for a lead-poisoned child.

In 2009, Germany lowered it again to 3.5 μg/dL for children and in 2012, the US CDC established 5 μg/dL as their intervention level (pdf).

But in Australia, after a review in 2009, the figure of 10 µg/dL was reaffirmed by the National Health and Medical Research Council (NHMRC), which provides advice to the Australian government (pdf). Since 2012, another review of that figure has been underway, with the results due sometime next year.

With the overwhelming mountain of evidence that Australia’s lead level for children is too high, we ask why would it take the NHMRC so long to undertake what appears to be a review of reviews, in the anticipation that they might conclude something different from other global experts?

Prevention of any lead exposure must be a key goal for the government. The current goal of 10 µg/dL is outdated and will inevitably result in harm to Australian children. We believe this goal should be cut to just 1 µg/dL. Even this figure is 62 times greater than ‘natural’ lead levels in humans. In the words of the NHMRC itself, “No threshold of lead exposure below which any exposure might be considered ‘safe’ in respect of cognitive abilities has ever been identified” (pdf). The time to act is now, because further procrastination will be the thief our future children’s opportunities. We have a moral responsibility to protect those who cannot protect themselves.

Read article at the ABC