I started to till the soil and noticed there was a lot of plastics. I dug deeper and soon realized that our yard was once an area where the previous owners incinerated their rubbish as I started to dig up very old and rusted steel drums which was the incinerator. I spoke to neighbours and they told me everyone used to do this in the area. We excavated the top soil and disposed a lot of it, I still didn't trust it. but it looked nicer.
I decided to pave the area and make raised garden beds and fill them with new soil. It's basically impossible to build them out of wood without lining them with something which may have negative health effects to humans or plants.
In the end I found an old stone / concrete planter, there's probably something in there bad for me too, but I just couldn't believe that even glazed pots contain lead?
In the US, even pottery intended for use with food may contain lead, to this day apparently:
"..there are no U.S. regulations (to my knowledge/correct me if I am wrong!) that specifically regulate the overall content of lead in pottery—even for pottery pieces intended for use with food and beverages."
https://tamararubin.com/topics/does-vintage-and-new-function...
https://tamararubin.com/2021/09/yellow-vintage-fiesta-plate-...
..which is mad of approximately 50% lead, and certainly no accident of nature.
And even if it were to occur naturally, that wouldn't make it any less hazardous.
There are plenty of known-safe materials to line garden beds with. Even unlined treated timber has been shown to be safe with only tiny trace amount of treatment making it into the plant. You might be being too paranoid for your own good.
And if that's not enough, choose one of the many other treatment options, or line your bed with a proven-safe polythene liner, or use untreated timbers that are resistant to rot like cedar/macrocarpa. If you have any real research to show that any of these options are unsafe I would love to read it.
The article contains some lists of know hyperaccumulators.
For example, sunflowers are known excellent heavy metals sponges.
Not so! Many types of wood (cedar is a big one) can withstand direct weather/soil exposure for extended periods of time (multiple years at minimum). Yes you'll need to maintain them every so often, but surely you aren't going into gardening not expecting to maintain equipment.