Urban Soil Sustainability

If soil contains toxic metals, what happens where the soil meets the root?  How might we use this knowledge to sustainably remediate contaminated soils? I study a fern, Pteris vittata L., which pulls arsenic out of the soil and stores it in its fronds. We then harvest the fronds to remove arsenic from the soil, leaving the valuable soil in place. Plant-based remediation techniques like this could eventually be accessible to community urban agriculture groups rehabilitating land for food production. As a former community farm manager, my goal is to conduct research to support community farming groups  in sampling soil and developing remediation strategies.