Healthy soils underpin food production, food quality and water quality. Contaminants can damage soil health, if they occur above critical concentrations. Contaminants in soil can arise from natural processes or, more commonly, from human activities. Some unwanted elements, such as nickel, boron and fluorine occur at high concentrations from natural processes during soil formation or subsequent deposition by natural events such as volcanic eruptions. Human activity, including agriculture, industry, transport, and military continually adds contaminants to soil.
For most contaminated soils, the cost soil clean up far exceeds the value of the land. Therefore, rather than returning soil to a pristine, uncontaminated state, contaminants in soil are usually managed so to minimise the risk that they pose to humans and ecosystems. Phytomanagement describes the use of soil conditioners and plants to create value from contaminated land, while minimising environmental risk.