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.
- AAP