Brownfield Remediation Clean-up Part III

Urban agriculture Has potential to improve the quality of life in urban areas by increasing food security, providing opportunities for community development, and improving the aesthetics of the urban landscape. Obstacles: land availability restricted budgets soil contamination.

Soil Contamination A major barrier to urban agriculture initiatives, because contaminants are present in most urban soils at levels higher than are accepted for agricultural use. These contaminants can be taken up by plants grown in these soils, and can be harmful to human health if the produce is consumed. The barrier of land availability could be partially overcome if brownfields could be used as sites for urban agriculture.

Remediation Remediation involves the removal of contaminants.

Physical remediation techniques Excavation Geotextiles Soil washing Soil vapour

Excavation refers to physically removing contaminated soil, normally for disposal at a landfill. Excavation is generally accomplished with heavy machinery. New soil is needed after the excavation.

Geotextiles are a synthetic blanket-like material. They can be used after the excavation process to provide a protective barrier, impermeable to contaminants which may otherwise migrate into the new soil after excavation.

Soil washing A technique which involves the physical removal of the contaminated soil, followed by treatment at a plant on or off-site. After the contamination is removed through the treatment process, the soil is put back into the ground.

Soil vapour extraction involves the installation of wells and pipes in the soil, through which soil contaminants are extracted in vapour form.

Biological Remediation Microbial remediation Phytoremediation Fungal remediation Compost remediation

Microbial remediation Refers to the use of microbes in degrading contaminants into a less toxic form. This technique can be very effective in the treatment of hydrocarbons, PAH's, pesticides, and PCB's.

Phytoremediation The process of using plants to degrade organic contaminants or to extract toxic metals from the soil and transport them into the above-ground shoots. In the case of extraction, the contaminated plants must later be disposed of soil.

Fungal remediation The use of certain species of fungus to degrade contaminants, particularly hydrocarbons.

Compost remediation The addition of compost to the soil. It is not a true remediation technique, as the contaminants generally remain intact in the soil. The addition of compost can, however, be used to create a raised bed, in which the plant roots may not reach the contaminated