Explain why phytomining is considered a more sustainable method of metal extraction than traditional mining, and describe what happens to the plants after they have absorbed metal compounds from the soil.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Some mining companies are turning to phytomining to extract copper from low-grade ores. In phytomining, plants are grown on soil containing copper compounds. The plants absorb and accumulate the copper compounds as they grow.
Model answer (4 marks)
Phytomining is more sustainable because it causes less environmental damage than conventional mining, which removes large amounts of rock and disturbs the landscape. It can also recover metal from low‑grade ores or soils where traditional mining would not be profitable. After the plants have absorbed the metal, they are harvested and then burned. The resulting ash contains the metal compound, which can be processed to recover the metal.
Examiner tips
- Use the word ‘sustainable’ and compare environmental impact; mention low‑grade ores; state harvesting and burning; mention ash contains metal
- Show clear cause–effect links and use exam terminology such as ‘low‑grade ores’ and ‘ash’
Common mistakes
- Confusing phytomining with phytoremediation; not mentioning low‑grade ores; saying the plants are simply discarded instead of burned
Mark scheme (4 marks)
- Traditional mining causes greater damage to the environment / landscape (than phytomining)
- Phytomining can extract metal from low-grade ores / soil where traditional mining would not be economical
- The plants are harvested / cut down after absorbing the metal compounds
- The harvested plants are burned to produce an ash that contains the metal compound / copper compound, which can then be processed to obtain the metal
Key terms in this question
Related
- All OCR GCSE Chemistry A: Gateway Science (J248) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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