What is phytomining and how does it work in the extraction of metal compounds from soil?

Phytomining is a method of extracting metal compounds from soil using plants. Certain plants are grown in soil that contains metal ions, and these plants absorb the metal compounds through their roots. Once the plants are harvested, they are burned to produce ash, which contains the metal compounds.

A strong answer should directly address the approved learning objective to describe phytomining as using plants to absorb metal compounds from soil. (HT only). This question belongs to Alternative methods of extracting metals within Using the Earth's resources and obtaining potable water, so the response should use that exact curriculum context rather than a generic statement. The answer is correct when it names the key idea, explains the link to HT only, and keeps the wording specific to AQA GCSE revision.