Dangers the Eye Cannot See

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Dangers the Eye Cannot See


September 29, 2009 12:01am

NO matter where you live, the air you breathe, the water you drink and the food you eat is likely to be contaminated.

The list of ingredients in your chemical cocktail is growing.

There are nanoparticles from some toothpastes, cosmetics and sunscreens, persistent chemicals from fire-fighting foams and traces of drugs that were once taken by other people.

But the sad truth is, even the world's best environmental scientists simply don't know how to clean up the mess.

They don't even know how many sites are contaminated, but they're happy to share their best guesses.

The number of potentially contaminated industrial sites in Australia is thought to be about 100,000. In the United States, 450,000. In Asia, three million.

These sites, known as brownfields, are most often associated with heavy industry such as petroleum refineries, sites of coal gasification or mineral processing, and manufacturing....


Nanoparticles: Extremely small particles (less than the width of a human hair) with various uses in a range of industries and modern products such as toothpaste, cosmetics and sunscreens.

Endocrine disrupting chemicals: Residues of drugs and personal care products such as shampoos and toiletries that can disrupt the normal function of sex hormones. Typically found in wastewater and solids sent to wastewater treatment plants.

Toxic residue from illicit drug manufacture: The walls, floors and ceilings of clandestine laboratories set up in private homes or buildings become contaminated by volatile compounds that move through the air and settle on surfaces. Waste is often disposed down drains that are not suited to the purpose.

Electronic waste: Old computers, televisions and mobile phones contain dangerous chemicals and heavy metals that should not be sent to landfill. They can leach into the water table.

"The major challenge that we are faced with is dealing with hundreds of thousands of contaminants," he says. "These are not present by themselves, they are present as mixtures. Dealing with mixtures makes it that much more challenging and more expensive."

Professor Naidu is managing director of the Co-operative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), based at the University of South Australia.

He wants to work in collaboration with scientists and industries from around the world under a formal system designed to tackle the challenges presented by emerging pollutants head-on.

"Every day we have new chemicals added to the list of chemicals . . . If we have a global protocol we can bring together scientists who can better understand the behaviour of these chemicals and how we manage it," he says.

Head of plant biotechnologies at the Joint Laboratory of the Institute of Experimental Botany and Research Institute of Crop Production in the Czech Republic, Dr Tomas Vanek is most concerned about fluorochemicals left behind by fire-fighters. "It's very unusual that they are able to contain the run-off from the fire," he says.

"The run-off water then goes into the ground and ultimately into the groundwater supplies. The breakdown products of these materials are exceedingly persistent and once the groundwater is contaminated it's very difficult to remove these materials.

"They have very long half-lives, they will stay there and as you continue to contaminate groundwater the concentration will rise. Even if the material is not particularly toxic, you will sooner or later cross the toxic threshold and the groundwater will become unsuitable for use."

Dr Vanek says most people in the world have traces of fluorochemicals in their blood.

"One finds this material in the oceans, in the atmosphere and in animals such as seals and polar bears in the polar regions, dolphins, fish, birds and humans," he says.

"(It) is not only very widespread but it is very persistent in the environment. It is bio-accumulative, meaning organisms take it up (and concentrate levels up the food chain) and it's toxic."

PROFESSOR Roger Klein, a medical doctor and physical chemist based in Britain, wants the world to wake up to the potential dangers of nanotechnology.

"At this moment there are more than 800 products which contain nanoparticles, so it is high time to start some serious research to find out if they are dangerous or not. We simply don't know it or not," he says.

His team tested commonly used nanoparticles - titanium dioxide, zinc peroxide, aluminium oxide, fullerenes and carbon graphite fibres - on tobacco plant cells and found that at varying levels the molecules were toxic to the plant.

"In the past we used many chemicals in agriculture and industry, only to find out afterwards they were damaging to human health and the environment. We do not want to make the same mistake with nanotechnologies - releasing unknown materials that turn out to be toxic and then finding they are difficult or even impossible to recall or make safe," Dr Vanek says....
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