Hey gardeners in Victoria (Oz), did you know that the EPA will test your soil for you, one time?
You can send three samples (from different parts of the garden) and they'll test them and let you know what's up with your soil, and whether you have dangerous contaminants, like lead.
I'm checking before I plant my food forest garden, so I can decide whether to use our soil or go with raised beds.
https://www.epa.vic.gov.au/gardensafe
Edited to add the link.