Keeping a worm farm is an easy project
Worm castings -- AKA poop -- add valuable nutrients to the soil and is easy to make. The hardest part is making the bin and that's not difficult.
What do we know about heavy metals in soil? What do we know about lead exposure through soil and garden plants? What do we know about cadmium and arsenic in soils? What can I do if I’m at risk for heavy metals in my garden soil?