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.