Basically Macquarie University and the EPA are partnering in citizen science programs to receive soil and dust samples for testing. This is to provide them with data around contamination from lead and other metals, and in return you receive a report about the safety of your soil/household dust and what to do if the levels are unsafe.
VegeSafe through the Environmental Science staff at Macquarie University is open to all Australians and they request a donation starting at $20. Victorians are encouraged to use GardenSafe.
GardenSafe through the EPA is geared at Victorians, apparently has some extras and is free other than the postage to submit soil samples.
DustSafe tests household dust. They have testing facilities in England, Australia and USA, and ask for a donation starting at $20.
That top link again, to see all three programs and submit samples
Edit: Soil contamination also affects backyard chickens and their eggs.
I considered doing it here but between all the challenges in such tiny patches of earth it might not be worth the effort