Thursday, May 13, 2010

Arsenic toenails

Arsenic Toenails

By Catalyst, ABC Television, Australia, March 11, 2010
Watch the video at: http://www.abc.net.au/catalyst/stories/2843289.htm

Is the glittering prosperity from Australia's gold mining being tarnished by the environmental impact of extraction techniques? Dr Paul Willis meets up with researchers from the University of Ballarat who are collecting children's toenails to find out how much arsenic they contain.

TRANSCRIPT
Arsenic Toenails

NARRATION
Meet Rose. She's your typical 9 year old girl.

Rose's Dad
She's a fairly quiet child, but she's certainly enjoys living in this town and she's got lots of friends right over the whole town.

NARRATION
In fact there didn't seem to be anything unusual about Rose until she participated in an unusual study conducted in western Victoria looking at arsenic in the environment and the children.

Johnathan Nettelbeck
It turned out that Rose had the highest levels of all the kids tested. And ah so, you know, I was naturally quite concerned.

Dora Pearce
We thought there might be a problem out there because of the arsenic and the soil oo we decided to take a closer look.

Dr Paul Willis
And that 'closer look' took a most unusual form. Dora Pearce from the University of Ballarat set about collecting toenails from children across western Victoria.

Dora Pearce
We use toenails because collecting them is non-invasive. They're easy to store. Doesn't hurt the children to provide them. And they provide us a timeline over several months of what the kids have been exposed to.

NARRATION
Perhaps the simplest part of the study was the collection of toenails. The parents cut their child's toenails, put them in a plastic bag, and gave them to Dora!

Rose
Well Mr Schausen, our science teacher told us about bringing toenails to school and all the other kids giggled because the thought it was gross. But it's not actually that gross because virtually everybody has them.

NARRATION
The link between arsenic and toenails is a subtle one. If arsenic enters the body it can be excreted by shunting it into the toe and fingernails and hair. But why would there be any extra arsenic in the environments across Western Victoria? Western Victoria was once the largest producer of gold in the world. During the great Gold Rush of the 1850s and 60s thousands of people from all over the world rushed to this area in search of their fortunes.

Dr Paul Willis
Most of the gold was found like this, small traces finely spread through other rocks. So the rock was crushed, releasing the gold — and the arsenic.

NARRATION
Crushing quarts became an industry on a scale that now seems unimaginable.

Dr Paul Willis
One hundred years later and western Victoria is dotted with mulluck heaps and tailings heaps like the one behind me. Some of them contain hundreds if not thousands of milligrams per kilogram of arsenic.

NARRATION
Dora teamed up with Kim Dowling from the University of Ballarat, an expert in arsenic and other toxins in the environment.

Kim Dowling
In the mining process arsenic which is locked in minerals deep in the earth is bought to the surface, and it's oxidised which means it can be made more mobile and so it moves around and again that's the thing that can have an impact it's completely natural and if it stays here for long enough it will age and not be as mobile. But at the moment it stays in the lansdscape and we've got piles of the stuff.

NARRATION
So Kim suspected that there would be hotspots of arsenic dotted across the old gold diggings. Dora wondered if these presented any threat to public health. And that's why she started collecting toenails. But figuring out how much arsenic was in the toenails required a lot of work. And there were limits to what conventional lab techniques could say about how much arsenic there was in a sample and where it came from.

Dora Pearce
When you generally take a measure of the arsenic in the toenail clippings what you're getting is an average reading. And so the arsenic concentration at one time point can be much higher than it is at a different time point. So what we really need to be able to measure is arsenic concentration at a given time point so we know we can relate that back to the actual exposure that caused that.

NARRATION
Dora needed the precision and resolution that could only be achieved by a synchrotron. By using high-energy sub atomic particles a synchrotron can determine exactly what kinds of atoms are present at specific locations down to a few thousandths of a millimetre. Trouble is, when Dora was doing her study, the Melbourne Synchrotron hadn't yet come on line. She had to go to Chicago. Dora teamed up with Andrea Gerson to help navigate her way through the high-tech world of synchrotrons.

Andrea Gerson
I think with Dora's study what the synchrotron offered was the ability to map on a micron scale the arsenic distribution within the toenails and then go back to the regions of interest and interrogate the particular speciation of the arsenic at the positions within the toenails.

NARRATION
Slowly a pattern built up, not only of how much arsenic was in the toenail clippings, but more importantly whereabouts inside the samples the arsenic was located. And these results were astounding.

Dora Pearce
We found that about 10 per cent of children in our study had levels of arsenic in their toenails higher than what might be considered a "normal" dose and also we found about half had levels greater than the highest value recorded in a non gold mining area — but we do need a larger study to confirm those findings.

Dr Paul Willis
These astounding figures raise two questions: How were the kids picking up so much arsenic and was it enough to damage their health?

Dora Pearce
The arsenic species that we detected in the children's toenail clippings suggested that the arsenic was possibly taken up in two different ways. One way is that the arsenic is absorbed systemically through the body when the kids are out there playing in the dirt or they can also inhale the arsenic from dust when they're playing out there especially on the mine waste.

Dr Paul Willis
Locals and residents have long known that there is arsenic in the environment and most of them have taken sensible precautions against exposure to contaminated areas. But Dora's study suggests that simply trying to avoid contamination isn't enough.

NARRATION
Rose was one of the participants in the study and one of the first to have her clippings analysed by a synchrotron. Her elevated levels of arsenic were, at first, something of a mystery.

Johnathan Nettelbeck
Many people in the gold fields area would be aware that arsenic's associated with the mine tailings. We certainly wouldn't buy a house directly next to, you know, right on top of something like that. Um and we'd certainly, we'd keep Rose away from those areas.

NARRATION
The second question: 'Was this exposure to arsenic dangerous?' would prove more difficult to answer.

Dora Pearce
We really don't know what a safe level of arsenic in toenails is, especially not in children because the baseline study's really haven't been able to provide us with that information. Far more work needs to be done in unexposed populations so that we can tell what a background level is.

NARRATION
Dora's toenail study has revealed some worrying facts about arsenic in western Victoria. But there are thousands of gold mine sites right across the country and we just don't know how contaminated they are or if the locals are exposed to this historic toxic time bomb.

Kim Dowling
In fact there's a raft of metals and other elements that we're interested in. For example mercury is also in this system, ah cadmium, there's a raft of metals that could have impacts on human health and indeed one of the reasons Dora's study is so exciting is we can use the exact same technique to work out where those metals are coming from and if they are affecting people's health.

Dora Pearce
There's still far more that needs to be done to further elucidate the type of arsenic that's present in these clippings so we can work out what the general levels should be, how the arsenic gets there and what we need to do to be able to reduce the exposures in these communities.

NARRATION
For children like Rose, the priority now is to prevent any more arsenic from getting in.

Johnathan Nettelbeck
As that awareness grows, you know, across the whole community if there were, there were sensible things to do we would certainly do that.

Dr Paul Willis
The gold rush was a significant event in our Australian history. It formed the foundations for our nationhood. But there is also a more toxic legacy left behind by the gold diggers, one that could affect generations of Australian's and one that we are only just starting to become aware of.

Topics: Health

Reporter: Dr Paul Willis
Producer: Dr Paul Willis
Researcher: Dr Paul Willis
Camera: Don Whitehurst and Mark Farnell
Sound: Chris Coltman and Graham Fettling
Editor: David Tucker
Story Contacts: Dora Pearce

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