TESTING YOUR HOME FOR LEAD

Any house painted before 1970 is likely to contain leaded paint. Renovations which strip back or sand old layers can release millions of particles of lead dust into your home. To find out if your house paint contains lead you can purchase a simple lead testing kit, available from your local hardware store for around $30.

Leaded petrol was phased out in 2002, but the problem of residual contamination in soils remains, particularly in the older areas of cities. If you are concerned about your soils they can be sent for analysis by Macquarie University's VegeSafe program:

See Macquarie University's VegeSafe program

The Lead Group is a charity organisation set up to assist people with information on lead and lead abatement. You can order DIY sampling/ lab analysis kits to test if your paint, soil house dust and other surfaces contain lead from this site:

http://www.leadsafeworld.com/solutions/lead-group-diy-sampling-lab-analysis-lead-test-kits//

NARRATION

Coming up on Catalyst, could lead exposure in childhood lead to an adult life marked by violent crime?

Anja Taylor

New York today is a very different city to the one it was 20 years ago. For one thing, it's considered to be much safer. There's been a big drop in violent crime since the 1990s. It's a phenomenon often credited to the tough policies of this man, former mayor Rudy Giuliani. He may have done wonders in the Big Apple... ..but oddly enough, as the rate of violent crime plunged in New York, it also plummeted in Los Angeles, Atlanta, Chicago, in fact, all over the United States and in many other countries.

Assoc Prof Sammy Zahran

Well, there this compelling increase in crime rates from 1960 to 1990. The rate of violent crime in the United States quadrupled over this period. And right around the early to mid-1990s the violent crime rate began to tumble. And it fell suddenly, rapidly and unexpectedly.

NARRATION

Among all the possible explanations came a seemingly absurd proposition that the late-20 century crime wave was not so much a factor of changing economics, drug use or police tactics...

Policeman

Put your hands all the way up there.

NARRATION

..but the mass-scale exposure of young children to one specific element... ..lead. From leaded petrol emissions.

Professor Mark Taylor

It makes sense, and indeed we've undertaken similar studies in Australia which show a very strong relationship between lead in air and crime 22 years later.

NARRATION

Although it's just a correlation, studies of individuals also show high childhood lead exposure increases the likelihood of a life marked by crime.

Assoc Prof Sammy Zahran

Lead plays no useful role in the body. Even at low levels, it's associated with lower IQ, decreased memory, behavioural problems and increased risk of juvenile delinquency and criminality.

NARRATION

Despite a massive drop in lead emissions, childhood lead exposure remains a problem in some parts of Australia. Floating in the dust of our mining towns settled in the soils of our inner city gardens and peeling off our old Australian homes, lead lives on.

Professor Mark Taylor

Because it can be modified, we should modify and remove that as a detrimental affect on the outcomes of children.

Advertisement, Voice-over

Gasoline is the fuel that powers this modern age.

NARRATION

Perhaps the biggest crime associated with lead is that it was known to have serious toxic effects long before it was added to petrol.

Professor Mark Taylor

The Romans knew that it was a problem, they used to use lead in wine and they knew that it was a toxin. Perhaps, more pertinently, we've known since the 19th century that lead in dust and also at the turn of the 20th century that lead in paint was a problem for children. We had lots of information, there were lots of research reports, there were lots of medical reports that showed that lead was a toxic substance and caused serious neurological damage and in some cases, death.

NARRATION

In fuel, it was thought to be dilute enough not to matter. But decades later mounting evidence showed that even low levels of lead exposure could cause a drop in children's IQ. Lead in petrol and paints was slowly phased out, but by then much damage had already been done.

NARRATION

Associate Professor Sammy Zahran's study was one of a number of recent epidemiological studies which found strong correlations between lead emissions and violent crime rates. But what was intriguing about his study was he compared six very different US cities - San Diego, New Orleans, Atlanta, Minneapolis, Chicago and Indianapolis.

Assoc Prof Sammy Zahran

So, the cities were very different in terms of their demographic structure, they were different in terms of their income levels, they were different in terms of the metric tonnes of PB emitted and in terms of the aggravated assault rates.

NARRATION

When aggravated assault rates were plotted over time and compared to rising and falling lead emissions, the results were startling.

Assoc Prof Sammy Zahran

They had very similar-looking shapes in the sense that they both rose and declined, but they were separated by a mysterious 22-year period. And so the logic was that we had groups of children exposed to varying rates of lead graduating into the age/crime curve.

NARRATION

Most convincingly, the rates at which the violent crime dropped matched the speed at which those cities phased out leaded petrol.

Assoc Prof Sammy Zahran

So, in cities where the phase-out was steeper, the drop in the aggravated assault rate was steeper.

NARRATION

Correlation doesn't prove anything. And there is much scepticism surrounding the idea that violent crime waves are caused by lead exposure. But in a yet-to-be-published Australian study Professor Mark Taylor has found a similar correlation between peak lead emissions and peak violence, and not just in big cities.

Professor Mark Taylor

I've looked at Bullaroo, for example, which was a smelting town. They've closed the smelter now. We've looked at suburbs in Sydney and we've also looked at Port Kembla. So, there are a mixture of sources - smelting and also lead coming from gasoline. But at the end of the day it doesn't matter - it's lead in air.

NARRATION

For each of the seven towns he looked at, peak violence comes around 20 years after peak lead in air. The strongest correlation was seen in Earlwood in south-west Sydney.

Professor Mark Taylor

Earlwood was a site where there's no smelter activity - it's leaded petrol emissions. It's exactly what we're seeing in the United States - there's a peak in crime and the correlation is reliable across various places in New South Wales.

NARRATION

As the world's biggest exporter of lead, Australia has done very well from this precious metal. Here in Broken Hill, the lead and silver ore body has kept the town alive. But in the red dust, levels of lead are recognised as a constant, invisible menace to members of the community, especially the young ones.

Professor Mark Taylor

They're still crushing and producing really fine ore. Some of that's escaping and that is being deposited in and around Broken Hill. You can see on the house across the road there's quite a lot of accumulated dust

Anja Taylor

Yeah, it's full of dust.

Professor Mark Taylor

..on the boards.

Professor Mark Taylor

And indeed when you start to look at sort of little nooks and crannies, you can see the dust that's accumulated over time. So in here, for example... ..you can see the dust and indeed...

Anja Taylor

Yeah, it's very fine.

Professor Mark Taylor

Extremely fine. And it's this sort of dust that blankets the city, blankets gardens, play schools, playgrounds et cetera. And you can see some of the minerals sparkling there on my finger.

NARRATION

Mark's dust-monitoring in the playgrounds of Broken Hill shows that a fine layer of lead dust contaminates the surfaces daily.

Professor Mark Taylor

So, we did a study where we played on the playgrounds for ten minutes, and we wiped the hands after play. Within ten minutes the concentration of lead and other metals on the hands significantly exceeded, in most cases, safe benchmarks.

NARRATION

The town is very aware of its lead risks and children are monitored by the health centres regularly.

NARRATION

But despite efforts to reduce lead exposure, a fifth of the town's children have a blood lead level over the current Australian benchmark of ten micrograms a decilitre.

NARRATION

It's at this level, Australian medical authorities recommend investigating the source of lead exposure. But it's widely recognised that there is no safe level.

Professor Mark Taylor

Indeed the natural level of lead in pre-industrial humans is 0.016 micrograms per decilitre. The current Australia goal which is under review is 10 micrograms per decilitre. That's 625 times the natural levels.

NARRATION

The US have already lowered their level of concern to 5.

Professor Mark Taylor

We're collecting data in all of the primary school catchments. So we're trying to understand the relationship between atmospheric deposition and the risk to children's blood lead exposure. We're also focusing on areas where there's known levels of elevated blood lead in children.

NARRATION

Mother-of-three Pam has covered all dusty areas in her garden with layers of gravel, and the rest is lawn and pavement. Yet despite her best efforts, her son's lead level recently spiked to 9 micrograms a decilitre. They've since come back down.

Pamela Stuchbery

I initially was panicking, and thought 'What has happened for the lead level to increase?' I don't know if we'd become a bit complacent with hand-washing, but we couldn't really link anything to why it had.

Professor Mark Taylor

Children have a greater predisposition of hand-to-mouth behaviours - they eat soil, they put things in their mouth, and if those articles and toys, for example, are covered in lead dust, they will ingest it. And so in a leaded environment where there's lead dust on those articles or on their hands, it's really, really difficult to prevent that exposure, which is why it's very, very important to implement primary prevention to stop the lead escaping from sites before it gets on to homes and domestic residences and those types of places.

NARRATION

Chad Hines grew just a couple of hundred metres from Bullaroo's now-demolished lead smelter. So, this whole area was the lead smelter?

Chad Hinds

The smelter was pretty much right here, all in that area there. I was always outside playing as a kid, in the dirt, always digging the dirt up and had no idea of how toxic the dirt actually was. That's where we used to play, all up in here. Stacks would just blow all of the stuff straight over here.

NARRATION

His mum Lyn believes Chad would have lived a very different life had she understood the risks.

Lyn Hinds

Chad used to sit in a play pen out on the front of the house. He was just totally taken in by it. The Tonka trucks were over there. I usually had to walk with him over there and he just thought it was great. As he went to preschool, the teachers at preschool used to say 'Chad's got a long way to catch up to the other kids.'

Chad Hinds

I never passed any of me tests, like, you know, end-of-year tests, and I wouldn't pass 'em, and I always had behaviour problems, I was always in trouble. Not being able to read, I'd get really scared when I had to read in class. The school, they were trying to say that, you know, there was no lead problem Mum took me to get tested at the health clinic which was in Bullaroo, and my lead level come back and it was 29.

Lyn Hinds

If someone had walked down the road dressed as misted lead, you know, with lead falling out, it'd be fine, people would understand, but there was nothing like that -

Lyn Hinds

it was just, um...

Anja Taylor

It's invisible.

Lyn Hinds

..yeah, Pasminco saying, 'No problem'.

NARRATION

Of all the troubles Lyn's faced, the hardest to manage has been Chad's explosive temper.

Chad Hinds

I get agitated really bad, like, I got anger issues and I've been in a lot of trouble with the police. AVOs - Mum's put about six AVOs on me, I think. I had about four mates that have got the same problems as me. Yeah, been in trouble with the law - high lead levels, same thing.

NARRATION

But every child is an individual. Can Chad really blame his run-ins with law on lead poisoning? The Port Pirie study in South Australia is one of the longest-running studies in the world on the developmental effects of elevated lead levels in children.

Four Corners Footage, Woman

OK, now, see these blocks, they're all alike. On some sides they're red, on some sides they're white.

NARRATION

These children grew up near the largest lead smelter in the world. A new review from the University of Adelaide found lead had a measurable but small impact on their lives compared to other factors.

Dr Amelia Searle

Children with higher blood lead levels were a little more likely to experience poorer cognitive and emotional and behavioural development. And also into adulthood, we did see - more so for females - the association between lead levels and mental health difficulties. But these associations were small once we started adjusting for and considering other early childhood factors that may have also been influencing their development - things like parents' socio-economic status, their education levels, whether they were employed or not.

NARRATION

One aspect the Port Pirie study didn't look for was an association between childhood lead exposure and violent crime.

Dr Amelia Searle

Port Pirie has never really been the focus for high crime levels or delinquency. So, looking at Port Pirie, we definitely wouldn't be making any suggestions that lead exposure and delinquency are correlated - it's definitely not anything we've seen.

NARRATION

But on the other side of the world in the US state of Ohio, an even more comprehensive long-term lead study has looked at the association.

Prof Kim Dietrich

We have the best measures of exposure on an individual level, and the best measures of individual outcome of any lead study that has ever been conducted in the world.

NARRATION

The Cincinnati lead study has been running for 35 years, but there's no smelter in this town. Here, the principal danger comes from rundown older housing.

Prof Kim Dietrich

Lead paint residues, no question about it. When we started this study in 1979 there was actually a real debate and real question as to where lead exposure was coming from. We initially started with about 400 pregnant women and we specifically targeted areas of Cincinnati, Ohio, where there has been historically a high incidence of lead poisoning going back to the 1950s, where there was pre-World War II housing and a high amount of lead dust. We started in the first trimester of pregnancy and got a measure of lead in the mother's blood while she was pregnant. Then we got a measure of lead in the blood when the child was born, and then every three months until they were six-and-a-half years of age. No other study in the world has ever done this.

NARRATION

Professor Kim Dietrich followed the children all the way into adulthood and saw significant and continuing effects from lead exposure, including lower IQs and behavioural and neurological problems after adjusting for many other influencing factors.

Prof Kim Dietrich

Their mothers and their girlfriends and their aunts and others would come to me and say things like, 'Why can't my son hold on to a job? Why am I angry all the time? Why am I having problems maintaining a stable domestic relationship?' And I looked at their lead-exposure histories and what I found was more often than not is that they had high blood lead concentrations. And these blood lead concentrations were mostly found in individuals who had a history of criminal behaviour, repeated incarcerations, domestic violence and other issues. So, what we did is we continued to follow these subjects into adulthood to see if this trend continued. What we found was very interesting. We found that those with the highest levels of lead exposure continued to engage in criminal activity. Not just during adolescence, but also it pushed them into an early adult criminal career, which included homicide - which was rare - but also assault, rape, those sorts of behaviours.

NARRATION

The main problem with lead lies in its similarity to calcium, one of the main players in the brain. From birth to adulthood, lead can interfere with calcium's critical processes, as billions of neurons grow and connect. MRI scans conducted in early adulthood reveal changes in the brain may account for the association with violent crime.

Prof Kim Cecil

We found, for brain volume, that the higher their childhood blood lead level was, the smaller their brain was, particularly in the frontal cortex, the region of the brain that really makes us most human. It's our decision-making ability, our emotional control, our judgement, it's the part of the brain that's really essential for proper functioning.

NARRATION

Most critically, the frontal cortex is the part of the brain that controls impulsivity - the anticipation of consequences, and aggression.

Prof Kim Cecil

We found on the order of 2% volume loss, or shrinkage, of their brain. Just to give you a sense of scale - disease... when we see a neuro-degenerative disease, we see around 10% volume loss. So we're much smaller scale, these participants can live what's essentially a normal life, but the lead had done a damaging effect to them.

NARRATION

They found reductions in certain brain chemicals and in the myelin sheath around the axon of neurons that helps messages travel faster.

Prof Kim Cecil

When we did functional MRI, we did a verb-generation task where we asked the participants to think of verbs when we would present them with a noun. And we could see that the regions of the brain responsible for language were damaged in a dose-dependent fashion. Language function focuses to the left hemisphere of the brain.

NARRATION

But in the Cincinnati lead study, participants used both sides of their brain in the language task, an indication the brain is trying to compensate for damage.

Prof Kim Cecil

We saw effects in everyone, however, the greatest effect are in those who had higher mean childhood blood lead levels.

NARRATION

The IQ scores from participants in the Cincinnati lead group were fed into a larger international study which determined the greatest fall in intelligence occurs in the lowest range of exposure. Children with a blood lead level up to ten micrograms a decilitre lost on average of seven IQ points. Kim Dietrich doesn't consider this a small drop.

Prof Kim Dietrich

Oh, I'd kill for seven IQ points. (Chuckles) No, no, seven IQ points is not small - it's a big effect.

NARRATION

It's worth pointing out that two decades ago when leaded petrol was still being phased out, the average blood lead level of Australian children under five was over five micrograms a decilitre. Recent studies now put the average level under three. So the danger from lead in petrol has disappeared long ago. Right?

Professor Mark Taylor

In terms of the legacy, those emissions have not gone away. About five million tonnes of lead have been emitted into the American environment from the tailpipes of automotive vehicles. In Australia, it's about 235,000 tonnes. The lead does not go away, it resides in the soils and it also resides in the dust that permeates homes, in the inner parts of Sydney, for example, or Melbourne or Brisbane.

NARRATION

Mark's program Veggie Safe has been mapping how much of that lead is in Sydney gardens.

Professor Mark Taylor

So, we'll just test this garden bed here where they're growing their veggies.

NARRATION

Over 500 homes have been sampled. In some of the busiest parts of the city, he's found soil lead concentrations that rival those in Broken Hill. This home in Balmain is metres away from one of the busiest roads in Sydney. We're here to test the veggie patch.

Professor Mark Taylor

We're gonna test the upper part of the soil, effectively, the top couple of centimetres. It's those particles that are likely to get onto the food plants. And also it's the part of the soil which is most easily interacted with children. So, we'll just put the XRF down on the soil.

Professor Mark Taylor

And the lead in this soil has a reading of 202 milligrams per kilogram.

Anja Taylor

That's quite good, isn't it?

Professor Mark Taylor

The standard for residential gardens in Australia is 300 milligrams per kilogram. The natural level of lead in soil, in Sydney, is between about 20 and 30 milligrams per kilogram.

NARRATION

This veggie patch has been constructed with fresh, brought-in soil, and it's OK... ..but it's the rest of the garden home-owner Angela's been worried about. Her hens, which peck and bathe in the dusty corners of the yard, haven't laid an egg in three months.

Dr Angela Webster

We weren't completely naive to the idea that there could be some contaminated soil in this area - it's been a big industrial area in the past. It's just it's residential now. And we did what we could. We actually totally changed the layout of the garden, we've brought in over seven tonnes of topsoil and sand.

NARRATION

When Mark tested the soils, Angela got a nasty shock.

Dr Angela Webster

The lowest level we had on our plot was 600 in the middle of the lawn. The chicken coop was over 900, the back of the garden was 1,500, the side of the house was 2,500 and the front garden was 1,400.

NARRATION

To put those figures into context, this chart shows the likely lead exposure of a two-year-old, based on the soil lead levels in their environment. At just over 1,000 milligrams a kilogram, the blood lead level is likely to cross the ten-microgram mark. There's many areas in Sydney where readings are over 1,000 milligrams a kilogram, and most of these are close to busy highways.

Professor Mark Taylor

The pattern that we see in Sydney of higher soil lead levels in the inner parts of the city and less in the outer parts, is replicated all over the world - New York, Paris, all the cities in London - it's classic, and the levels are rather similar wherever you go.

NARRATION

Although Angela remediated her soils, there's potential contamination from a nearby construction site which has been stirring up a lot of old dust. And the house is old and has peeling paint. It contains around 4% lead.

Professor Mark Taylor

I think this is one of the things that we've realised when we've been doing this work - that people have forgotten really, about the risk of lead in paint. I've been to houses before and spoken to the parents of children where they inadvertently contaminate the house and raise the blood lead levels of children by sanding old paint which its quite rich in lead - it can be up to 50% lead. That generates billions of small particles that permeate the house.

NARRATION

With all the recent studies showing low levels of exposure can be harmful, the current Australian guideline of ten micrograms a decilitre is under review. It's likely to be lowered to five sometime this year. From his calculations, Mark Taylor estimates 100,000 Australian children could be over this reference value. So what can we do about it?

Professor Mark Taylor

If I was to apply the primary rule for public health, which is primary prevention, I would recommend that we go back and look at what's going on at the operations in these towns - Mt Isa, where blood lead levels appear to be falling, Broken Hill, Port Pirie, - and look at what's going on on site and how can we reduce dust coming off that site? In terms of the decoration of your house, you have to call a professional decorator and get somebody in to remove that paint professionally or to seal it. If you're worried about exposure from other sources in your house, such as paint and such as the soil, you can take those samples and you can get them tested at scientific laboratories. The view that I take is that all our children are the future for Australia, and I think we have a duty to protect those children from modifiable exposures that exist in the environment, and lead is a modifiable exposure, particularly in mining and smelting communities.

Prof Kim Dietrich

There has been no real resolution to this problem. There has been a real resolution to the problem of atmospheric lead with the elimination of lead from gasoline, but children living in our inner cities have not been the benefactors of this reduction of lead and gasoline, because they are still living in a world of lead in our inner cities.

NARRATION

Although far from proven that lead emissions is the culprit behind violent crime waves in the developed world, it's troubling that a handful of countries still use leaded petrol, including Iraq and Afghanistan. And children in nations with less-stringent mining and industrial rules are suffering severe developmental defects, and in some cases death, from high levels of lead exposure.

Prof Kim Dietrich

Nigeria, where hundreds of infants have recently died as a result of lead exposure from artisanal goldmining... ..it is the most important, most dramatic, most significant environmental health disaster and it does not seem to get any attention at all.

NARRATION

For more on the Nigerian lead crisis, visit the Catalyst website, where you'll also find information on how to test your home for lead, and background on the studies mentioned in this program.