Plants and microorganisms often have symbiotic relationships, making the root zone, or rhizosphere, a very active area of microbiological activity. Plants can help moderate the environment in the root zone, providing ideal conditions for bacteria and fungi to degrade organic pollutants. Certain plants hyperaccumulate metals, radionuclides or organic compounds. These plants can be placed in areas of contamination where they remove the contaminant. Afterwards, the plants can be harvested and the contaminant can be disposed, destroyed or recovered.
Many plants require large amounts of water in their daily lives.
Some plants contain enzymes that can destroy contaminants. Phytoremediation is attracting much attention as a low cost treatment alternative. However, phytoremediation has several limitations that must be considered. In situ phytoremediation is limited to shallow soils or aquifers. Phytotreatment is likely to be slower than excavation, incineration, adsorption or chemical treatments.