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How to Cleanse Soil of Metal

Soil contamination is a serious issue near many mining and industrial sites. Metals such as arsenic, cadmium, chromium, lead, zinc and nickel may settle into the soil, making it too toxic for vegetation to grow. Rain may wash the metals into nearby waters sources, rendering drinking water in the area non-potable. The traditional way of dealing with this problem has been to dig up the soil and take it somewhere else. But this is extremely expensive and simply shifts the problem to another site. A more recent solution is phytoremediation -- using specific varieties of plants to extract the metals.

Things You'll Need

Fencing
Shovel or tractor, depending on the size of the contaminated area
Protective gear

Instructions

- 1
  Plant appropriate species on the contaminated land. Although most plant species cannot grow in soil with high metal content, some plants have a higher tolerance and a few species even thrive there. Some mustard species are very good at absorbing chromium, lead, copper and nickel. Other species that do well are alfalfa, cabbage, tall fescue, juniper and poplar trees.
- 2
  Set up fencing around the area, to keep out animals and people. Animals that stray into the site and eat the vegetation may bring the contaminating metals into the food chain. Netting may need to be put over the site, if birds are a problem. The fencing should be tall enough to keep out leaping animals such as deer, and secure enough at the base to keep out smaller animals such as rabbits.
- 3
  Harvest the plants by either pulling them up or cutting them off at ground level. If the plants store metal compounds in the roots, they must be pulled out completely. But if the metals are stored in the leaves or stems, they can simply be cut off. If the plants are perennial, the bases can be left to grow for additional seasons, to absorb more of the metallic contaminants.
- 4
  Dispose of the plant material in an appropriate manner. If you burn the plants in large enough volume, the ashes can be smelted to recycle the metal content.

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