There are close to 160,000 toxic sites in Australia, says an environmental health expert whose main concerns include mines and old railways.
There's not much people can do about toxic dust or poison leaching into groundwater, says Professor Ravi Naidu.
However, at the very least they should keep away from old railway lines, which are poisoned with herbicides and pesticides that include arsenic.
Prof Naidu's organisation, CRC CARE, is hosting 150 delegates from 40 countries at CleanUp 2013, a Melbourne conference aimed at finding solutions for toxic sites around the world.
Topics discussed at the conference include the world's ever-growing garbage pile of electronic waste and how it is poisoning children.
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Delegates are also discussing global contamination and its impact on health, economies and ecosystems.
Poisons like lead and arsenic are big problems in Australia because of past practices in the mining industry, says Prof Naidu.
Electronic waste is also a problem because it used to be disposed in landfill sites before appropriate legislation was passed.
"We have many old landfill sites that have received electronic waste but do not have appropriate barriers.
"As a consequence we have contaminants leaching from the electronic waste and there is evidence of this in ground water."
For children the biggest concern is toxic substances in the air.
These could be from domestic carpets, for example. But children living close to mining areas are at particular risk of being exposed to lead in dust particles.
"The main message for Australians is to be aware of the danger of toxic substances in the air and to be aware that contaminants are present where ever there are old railway tracks.
"Keep your children away from them. They are not always fenced off."
He says the government and industry needs to do more.
"There should be improved mine processing techniques that do not generate as much dust."
Most toxic sites in Australia are in urban environments and people living nearby are often not aware.
"We should be concerned that with so many potentially contaminated sites the pace with we are rehabilitating them is very slow," says Prof Naidu.
